Step 4
Properly Sized, Designed, Installed, and
Commissioned Heating, Ventilation, and
Air Conditioning (HVAC) Systems
•1
The 7 Steps of Building a Synergy Home
1. Airtight Construction
2. Fresh Air Ventilation
3. Improved Thermal Systems
4. Pr...
Proper HVAC sizing, design,
installation, and commissioning in new
residential construction
is mostly ignored and rarely a...
A few things about the HVAC industry :
• It is extremely price driven. Many profitable HVAC contractors refuse to
bid on n...
Studies show that the average
HVAC system delivers only 57% of
the rated British Thermal Units
(BTUs) into a home.
• Where...
Most people….
Want/Specify
• Granite countertops
• Cabinets
• Appliances
• Flooring
• Landscaping
• Additional square foot...
Some people attempt to build an
energy efficient home by spending
extra money on products that are
improperly installed an...
Many homes including those marketed
as “energy efficient” or “green” are
experiencing:
• Major comfort issues.
• Indoor ai...
Let’s consider how homes built
today have changed dramatically
from how homes were built in the
past.
•9
1st Big Change - Insulation
• It keeps heat in or out.
• By keeping heat in or out, it prevents wall cavities from drying
...
2nd Big Change – Fresh Air
Ventilation is Required
• Numerous improved building products and
air-sealing decreases air cha...
3rd Big Change – Air Balancing and
Pressure Balancing is Required
• Tighter systems are easier to pressurize or
depressuri...
Today’s homes are interactive
systems that are made up of
multiple products, and most of all,
people.
• When just one prod...
Houses must be assembled onsite
with numerous parts and pieces
and subcontractors.
• HVAC systems are more than just the
b...
“Synergy” is defined as the
cooperative interaction among
multiple systems so that their
combined effect is greater than t...
“Synergy” is what sets us apart
from other companies!
• HVAC design, sizing, bidding, installation
inspection, and commiss...
We don’t sell HVAC equipment.
• We sell comfort solutions!
• We are 3rd Party design specialists guaranteeing energy effic...
Energy efficiency has never been so
inexpensive to finance. A 30 year
mortgage at 4% costs approximately $3.77
per $1000.
...
A ton of air conditioning is roughly
12000 British thermal units (Btu’s).
• Typically, we need between 350-400
cubic feet ...
Seasonal Energy Efficiency Rating
(SEER) is most commonly used for
evaluating the efficiency of an AC.
• SEER only applies...
Installing oversized, high SEER
rated equipment is not energy
efficient.
• The Federal Government has falsely led
homeowne...
In existing homes, whatever tonnage
the home got originally, will more than
likely, be the tonnage the home gets
when the ...
Rarely is the ductwork considered.
Changing out the unit without
considering the ductwork is like
getting a heart transpla...
The HVAC unit in this home was replaced
with an Energy Star 16 SEER unit without
repairing or replacing the ductwork.
•24
Most homeowners do not plan or
budget for an HVAC unit
replacement.
• Units often fail during the hottest or
coldest perio...
Check out www.escore.com for
rebate programs and financing so
you get a “Synergized” existing
home.
•26
You need to understand…
• Q = U x A x Delta T (QUAT)
• The importance of Manual J, S, D, and T.
• The importance of air fl...
What is a Manual J Load
Calculation?
• It is a complex calculation that determines the
heating and cooling requirements of...
Manual J Calculations consider
• Q = U Value x Area X Delta T
• Indoor design temperatures of 70 degrees for winter and 75...
An accurate Manual J Load
Calculation takes time and requires
a lot of information.
•30
Garbage in
=
Garbage out
• “Short forms” are inaccurate.
• “Block” load calculations are
inaccurate.
• Why bother?
•31
It is almost always more efficient and more
comfortable for your air conditioner to be
sized correctly so that it runs con...
When your HVAC system is not
operating it is not dehumidifying.
• The longer the system runs, the colder the
interior coil...
Every time your HVAC system
“cranks up” it is costing you money.
• Watt draw at initial start up is very high and
efficien...
What is a Manual S Calculation?
• A Manual S helps select the proper
equipment by matching the specific
equipment to the M...
Sensible cooling is actual
cooling/coolness you feel.
• This is measured by a drop in dry bulb
temperature.
• Latent is de...
We reduce internal latent loads by
• Proper air sealing of penetrations. Air must be
contained before it is controlled.
• ...
Most equipment manufacturers have
similar quality equipment. Chevy is to
Ford is to Dodge is to Toyota.
• Manufacturers of...
What is a Manual D Calculation?
• Manual D sizes ducts for the proper delivery
and return of the calculated air flow based...
The IRC Code requires Manual J,S, D, &
T’s!
Manufacturers require them!
•40
The Alabama Board of Heating, Air
Conditioning, and Refrigeration
Contractors require them!
•41
The Energy Star for New Homes
Program requires them!
Consult the “Energy Star for New
Homes Version 3 HVAC Checklist”.
•42
Many of the largest HVAC
companies with all the brand new
trucks and advertising don’t
perform Manual J, S, D, and T’s.
• ...
So why don’t most HVAC contractors
perform Manual J’s, Manual S’s and
Manual D’s?
• They never had to do them before.
• It...
The #1 Reason….
•This section of the
code is not enforced!
•45
What does a building code
inspector “inspect for” in the
absence of a Manual J, S, D, and T?
• What does a mechanical insp...
How did we get here?
• Am I the only one that this doesn’t make
sense to?
• Does anyone besides me find it strange that a
...
Can we blame an HVAC contractor
for over-sizing?
• Many reputable HVAC contractors have
never had control over the other
c...
When is the contractor most at risk for
construction defects?
• Code compliancy is not achieved. (Regardless of whether or...
Some HVAC contractors provide
Manual J, S,D, and T’s.
• Most are inaccurate due to the lack of understanding
of thermal bo...
Many HVAC contractors
• Size the HVAC unit by the square footage.
• Run flex duct from the supply plenum to the outside of...
As a rule of thumb, how many square
feet per ton should you figure?
•52
What does the typical HVAC
contractor charge per ton of HVAC?
• $1500?
• $2000?
• What do you pay?
• What do you charge pe...
How many HVAC companies will
price your HVAC system over the
phone without even looking at it?
• A 2000sf house / 500 x $1...
If the ductwork is not specifically
priced into the job then you can
almost be assured that you are getting
the bare minim...
The infamous spider box. In the second
picture, the unit is way oversized. When
the unit kicks on for a short period, how
...
The Air Conditioning Contractors of
America issued the HVAC Quality
Installation Specifications to help
address these issu...
Do you believe that you are going
to be the one person that gets a
high performance HVAC system
without planning, design,
...
How much heating, cooling, and
ventilation do you need if you have
framing bypasses, your house leaks,
your insulation doe...
How much heating, cooling, and
ventilation do you need if you build
the home perfectly but get a bad
ductwork design and i...
How do you know if you don’t size,
design, and then test your home
and it’s systems?
www.WeTestOthersGuess.com
•61
The Synergy Airflow and
Ventilation LLC HVAC design
process.
•62
We use Right-Suite Universal because
it is simply the best! We are simply
the best at using it!
•63
See “The HVAC Design Customer
Questionnaire” and our full size HVAC
Design example.
• We provide you with the proper
docum...
We average approximately 1200 sf per
ton which oftentimes results in
reducing your HVAC equipment by
50% or more.
• Oftent...
It is imperative you plan and design
the actual location of the HVAC
equipment and duct system.
• It cannot be an aftertho...
The IRC specifies maximum
distances from the crawlspace or
attic access to the equipment. The
location, the headroom, walk...
To most code officials, the ease of
inspecting and servicing an HVAC
system is more important than
proper location of the ...
Many house-plans/blueprints do
not provide space for the HVAC
system, especially the returns.
•69
What’s wrong?
•70
These ducts were crammed into the
attic directly under the roof decking
where they have large conduction
gains. Notice the...
We meet with you and review your
blueprints extensively, applying the
“Seven Steps of Building a Synergy
Home”.
• We discu...
We draw out the house and locate the
“thermal building envelope” using our
years of experience in the insulation
business....
Why would you ever install your
HVAC system in a 140 degree
vented attic or a 20 degree vented
crawlspace?
•74
Why not move the entire system into
the conditioned space? We can show
you how big of a difference it makes!
•75
Traditional fiberglass insulation in a crawlspace or
bonus room floor does not work due to the fact that it
must be in com...
R-values for traditional insulation such as fiberglass
batts entered into load calculations are assumed to be
correct. We ...
Heat pumps are ideal for foam
homes and encapsulated
crawlspaces. They have gotten a
bad reputation for comfort due to..
•...
In heating mode when the unit
doesn’t run except for short
periods…
• The warm air in the ductwork gets cold
when the unit...
Heat Pumps…
• Eliminate any problems associated with gas combustion.
• Require specific occupant behavior.
• Warm homes sl...
Gas furnaces must be direct vent / sealed combustion
units when installed in encapsulated attics or
crawlspaces. Low effic...
After we move the ducts into a
well insulated and air sealed
conditioned space, we focus on
airflow by designing your syst...
The static pressure of your
HVAC system is the equivalent
to your blood pressure.
•83
Air weighs approximately 0.075lbs
per square foot.
• 1 ton of HVAC requires approximately
350-400 cubic feet per minute (c...
Static pressure is measured in
inches of water column (IWC) or
Pascals.
• IWC is an HVAC industry measurement.
• Pascals i...
Single speed air handlers (PSC’s)
are typically rated at 0.5 inches of
water column (IWC).
• Variable speed fans (ECM’s) a...
A .5 IWC single speed fan is like a 40
mph single speed car
• Put it in gear and it attempts to go 0.5 IWC
(40mph) even if...
Why is a 0.8 IWC variable speed air
handler necessary?
• Duct systems have increased in size total length due to larger ho...
Everything the air passes through
in your duct system such as a
restrictive filter has an impact on
how much comes out on ...
Issues affecting the available static
pressure (ASP) of a system
• The static pressure rating of the fan motor. It is
usua...
Pressure loss assumptions over the
evaporator coil.
• During design we assume a pressure loss of
50% for the coil and filt...
Several manufacturers spec’s for the
coil drop on a heat-pump. Note the 5
ton Carrier listed at CAPV060 has a coil
drop of...
In addition to assuming a 50%
pressure drop across the coil and filter.
We also assume the following pressure
drops…
• Bal...
Realistic static pressure drops are
mandatory for correct duct sizing.
This is the static pressure screen
from our HVAC de...
Available Static Pressure Calculation
for a Variable Speed Fan
• Total Rated Pressure of Variable Speed Fan 0.8 IWC
• Pres...
Available Static Pressure Calculation
for a Single Speed Fan
• Total Rated Pressure of Single Speed Fan 0.50 IWC
• Pressur...
Available Static Pressure Calculation
with the manufacturer’s published coil
drop instead of a percentage.
• Total Rated P...
An Available Static Pressure (ASP) of .31
IWC is much better than .16 IWC.
• How do we design a system with only
.003 IWC ...
See our handout on “Static Pressure,
Friction Rate, and Total Effective
Length”.
• Friction Rate = (ASP x 100)/TEL
• ASP =...
An equivalent length of a fitting
can be looked up in the ACCA
Manual. It converts a particular
fitting such as an elbow t...
Friction Rate = (ASP x 100)/TEL
• 0.8 IWC Variable Speed Fan
FR = (.31 x 100) / 384 = .081
• 0.5 IWC Single Speed Fan
FR =...
A ductulator requires 2 specific
things to calculate the duct
diameter:
• Airflow in cfm for each room.
• Friction rate – ...
Ductulators are not accurate if
• The friction rate is wrong due to using
arbitrary numbers such as 0.1 IWC for supply
duc...
What happens if you calculate the
proper friction rate and you know
the proper airflow in cfm and you
determine you need a...
As we build super energy efficient
homes and reduce the tonnage
and specifically the airflow, it is
imperative that we get...
What about contractors that use the same
size branch ducts for every room in the
house? You cannot damper an 8” duct
down ...
Without the knowledge needed to perform
proper Manual J, S, D, and T’s, most
contractors rely on extra tonnage in order
to...
Our goal is to maximize the total
available static pressure by the
following:
• Using a higher rated fan such as a 0.8 IWC...
We have learned that most
homeowners will pay extra for…
• Single stage compressors with variable speed
air handlers.
• 2 ...
2 Stage / Variable Speed Compressors are
“game changers” in a diverse climate like
Alabama’s!
• 2 stage systems - 1st Stag...
What happens to the best designed,
most advanced unit when the interior
coil is filthy due to operation during
constructio...
Wouldn’t it be a good idea to have it
checked before you begin operating it?
• Coils that appear clean are often clogged w...
We simply recommend that you
never operate your HVAC system
during construction.
•113
Make sure the registers are covered during
construction and that the cut-outs are
removed from the crawlspace so that they...
Do not waste money on duct cleaning
services. Whatever caused them to
get dirty in the first place will most
often cause t...
An air filter’s main responsibility is to keep the
evaporator coil clean. Most filter systems choke
airflow and actually c...
It has been said that more HVAC
systems have been killed by Paul
Harvey, selling washable,
restrictive filters than any ot...
Lifetime Ecofilter’s are Garbage!
•118
Keep in mind that compressors
don’t die, they are murdered. 88
Pascals / 250 = .352 IWC
•119
Restrictive filters are often the
cause of major issues in a duct
system.
• Most filters are rated at 300 feet per minute
...
Understand how to recalculate
filter pressure drop using
Fan Law 2.
• Sp2 = SP1 x (CFM2/CFM1)squared
• The pressure drop o...
Limiting the numbers of filters that
need to be changed and centrally
locating the filter(s) are important
steps to consid...
We rarely recommend accessory
air cleaners. Building a home in
accordance with “The Seven Steps
of Building a Synergy Home...
Returns need to be properly sized and
should never be located in closets
even with a louvered door.
•124
Notice the interior air handler
insulation has pulled loose and is
choking the airflow.
•125
The placement of the air handler and the
individual registers must be considered in order
to decrease the length of the du...
The location of the outside
equipment is influenced by the…
• Electrical drops and runs.
• The length of the refrigerant r...
We witness package units
experiencing major issues in
sprawling homes due to….
• Oversized units.
• Single speed, 0.5IWC r...
We strongly recommend split systems
over package systems.
•129
We increase available static
pressure by installing ductwork
properly.
•130
Most ductwork is constructed of
round metal, square or
rectangular metal, ductboard,
and flexduct.
•131
Flex duct is not a problem if it is
designed, sized, installed, and
commissioned properly.
• Flex duct is relatively inexp...
This is in brand new construction!
•133
Proper supply transitions out of
the air handler are needed.
•134
Do not use framing members as
supply ducts.
•135
The wall framing is being used as a
supply trunk to deliver air from the air-
handler located in the attic over the
2nd fl...
This installer found it easier to run a 360
instead of cutting it to fit.
•137
The holes cut for flex duct must be
adequately sized so that the ducts are
not pinched. Structural integrity of the
framin...
This is a two story home on a slab with
the 1st floor ducts ran from the attic.
Two story slabs are hard to duct
properly ...
Unplanned ducts under cabinets restrict
proper throw from the registers. If a duct
needs to be located under a cabinet, pl...
Decorative wood registers
oftentimes severely restrict airflow.
Note the extra airflow allowed by
the register on the righ...
Things to consider for proper register
placement especially since it is no longer as
important to locate HVAC supply regis...
The AED Assessment shows when zoning is needed.
Zoning is rarely needed in a “Synergy” home. Interior
window covering and ...
Could a severely pinched duct decrease the
available static pressure and create
premature equipment failure? Do you
think ...
Notice that there is no “backbox” on
the return side. This kills the airflow of
this system.
•145
“Back boxes” help to reduce
turbulence, reduce static pressure, and
increase airflow.
•146
Do not use framing as return plenums.
•147
What happens if you have a supply
side leak?
• Supply leaks “suck”.
• You lose conditioned air to the exterior, the
house ...
Many times we find a “bleeder” that
goes unchecked until major issues
develop. The blower door will actually
help locate m...
The IRC requires “boots” must be
sealed to the building envelope unless
located inside the conditioned space.
•150
What happens if you have return
duct leakage?
• Returns leaks cause your home to “blow” or in
other words become pressuriz...
In many of the homes we test, as
much as 50% of the return air is
missing. Where is it going? Was it
ever there to begin w...
Many coils with low airflow are not
freezing up because air handlers are
located in 140 degree attics and the leaky
return...
Notice the white insulation has turned
gray from filtering air pulled in through
this return leak. Return duct leakage is
...
Locating the attic access inside the conditioned
space in a traditionally vented attic is a bad idea,
especially, if is it...
The net difference in the supply
side leakage and the return side
leakage causes increased air
infiltration in the home. M...
Never close off bedrooms or duct
registers. In a foam house, we
install jumpers ducts and let the
unit run.
•157
What happens if you do not have proper
return pathways and you close your
bedroom doors?
• Air that is supplied to the bed...
Symptoms of pressure issues
• Interior doors close when your unit starts up.
• You smell your fireplace when your heating
...
Once your HVAC system is properly designed,
sized, and installed….make sure it is airtight.
Plumbing is checked for leaks,...
Duct-sealing a properly sized,
designed, and installed HVAC
system is one of the most cost
efficient measures a homeowner
...
Duct-sealing undersized and improperly
designed ductwork increases the static
pressure and creates additional problems
tha...
We offer static pressure testing
along with duct tightness testing.
• Few builders and homeowners want it
since it is not ...
Duct tightness standards if ducts
are not installed inside of the
thermal envelope
• 4% of square footage at rough in with...
Air handlers need to be air-sealed,
especially if they are in vented
attics or crawlspaces.
•165
•166
71.8 pascals + 234 pascals
= 305.8 / 250 = 1.22 IWC.
1.22 IWC should be 0.5 IWC or less.
This unit is having a stroke!
•167
Smart systems display the static pressure on the
thermostat as well as the cubic feet per minute
of airflow. Note this uni...
A typical HVAC system requires
approximately 350 - 400 cubic feet
per minute of airflow per 1 ton of
heating and cooling. ...
Static pressure readings used with
manufacturer’s fan data gives us the
actual airflow.
•170
In units with high static pressure,
the rated 1800-2000 cfm of airflow
is often found to be around 1000 -
1200 cfm or even...
We measure the actual return airflow with
a flowhood and compare it to the rated
airflow of the system. Note that the
flow...
Notice that the delivered cfm of this high SEER unit
with bad ductwork is 1957cfm. Smart systems attempt
to overcome high ...
Note that when the work of the fan
is increased, the watt draw is
increased by a factor of 3.
Fortunately, when the work o...
This is too much info
but
Fan Law 3
3
Amp2 =Amp1 x(CFM2/CFM1)
•175
Make sure the dip switches or speed taps
are set up properly so that proper airflow is
delivered. Most are never adjusted ...
Why is low airflow bad?
• Comfort requires proper airflow in order to
supply and return the right amount of air at
the rig...
Refrigerant Charge & Airflow Test
Methods
• Common but not
Recommended
 Charge Tests
– Pressures
– “Beer can cold” suctio...
Line sets must be properly evacuated and
brazed with nitrogen. Does your HVAC
contractor even own an evacuation pump?
Coul...
See Any Issues?
•180
Digital gauges must be used to confirm
proper charge after proper airflow is
confirmed. Analog gauges are
inaccurate.
•181
Temperature Diagnostics and
System Efficiency
• Temperature Diagnostics helps demonstrate the advantages
of bringing ducts...
Measuring Entering Return Grille
Temperature
•183
Return Duct Loss or Gain
Return Duct Temperature Loss
=
Return Grille Temp – Return Plenum
Temperature
Heating
70 – 63 = 7...
Supply Duct Loss
Supply Duct Temperature Loss
=
Supply Register Temp – Supply
Plenum Temperature
Cooling
64 – 55 = 9
•185
System Loss or Gain
System Loss %
=
Duct System Temperature Loss/
Equipment Temperature Change
Cooling
9 / 18 = 50%
Assumi...
If you measure the system temperature
loss on a mild day or on a summer day in
the morning you might get a system delta T
...
System Delivered BTU Calculation
Heating
=
Actual CFM x system delta T x 1.08
A 3 unit is found to be moving 850cfm of air...
System Delivered BTU Calculation
Cooling
=
Actual CFM x system delta hT x 4.5
Cooling requires converting the delta T into...
You can perform a perfect Manual J & D
calculation and a perfect installation and
still have major comfort issues due to
i...
We confirm the total system
airflow with a flowhood and then
we measure airflow and velocity of
the individual supply duct...
Ducts are sized to the worst case total effective length
(TEL) which is the length from the longest and most
restrictive s...
Many HVAC companies do not install
balancing dampers. Of the companies that
do install balancing dampers, they rarely
use ...
We rarely have to be concerned
with excess velocities.
Volume of air in CFM
=
Area in square feet of the duct
X
Velocity i...
Recommended Velocity (in fpm)
Supply Return
Duct Type Rigid Flex Rigid Flex
Trunk 700 600 600 600
Branch 600 600 400 400
O...
Notice the velocity at this supply
register is 1414 feet per minute. It
sounds like a jet.
•196
4” x 12” register = 48 sq inches
48/144 = .33 sq ft
CFM = .33sf x 1414fpm
CFM = 466
Note that this one register has over
1...
We use Wrightsoft to calculate
trunk reductions. It does so when
velocity in the plenum reaches 50%
of the original veloci...
We design your duct system to
handle the total airflow at full
capacity. When the unit is
operating on 1st stage, the stat...
We are able to show you how fresh air ventilation
affects the load of your home. We can show you the
difference between “s...
Never run your fan in the “on” position
in an attempt to ventilate the home.
Always run it in “auto”.
• Leaks in the duct ...
Make sure the p-trap is properly installed to
prevent condensate from being pulled back in
and redistributed throughout yo...
“Gook” build up in a condensate
drain. Has anyone seen this
before?
•203
Make sure your condensate is properly
drained away from the foundation.
•204
Make sure you outside condensing
unit is free of vegetation and
blockage.
•205
Make sure a high quality thermostat is installed on an
interior, air sealed wall, away from heat sources and
direct sunlig...
Lockout thermostats are required
by the 2009 IRC to prevent electric
heat-strips from operating until the
temperature drop...
Geothermal units along with the
entire HVAC system qualify for a
30% rebate from the government
until 2017.
•208
We often witness homeowners spend
large amounts of money on a
geothermal unit(s) while…
• Purchasing single speed units.
•...
What is the correct solution for a
single upstairs room or bonus
room that is calling for only 1 ton?
• Do you install a c...
Ductless mini-splits are great for
certain applications such as bonus
rooms and light commercial
applications.
•211
My favorite ductless mini-split
picture
•212
Demand proper documentation
and owner’s manuals for all of
the HVAC equipment.
• HVAC systems must be properly serviced an...
Low priced HVAC systems are most
often low quality HVAC systems.
•214
• 13 SEER, single stage, permanent splits
capacitor (PSC) units start at 1.5 tons and
increase by half tons.
• 14 SEER var...
An air-conditioner works by delivering liquid Freon through the refrigerant
line to the cooling coil in the air-handler un...
Questions?
todd@synergyairflow.com
www.WeTestOthersGuess.com
•217
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Step 4 - Properly Sized, Designed, Installed, and Commissioned HVAC Systems

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This is the comprehensive powerpoint for having a Properly Sized, Designed, Installed, and Commissioned Heating, Ventilation and Air Conditioning System.

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  • Most “so called energy” efficient homes do 1 & 3 and duct test.
  • We will talk about pricing later in the presentation!
  • Btu’s are a measurement of the heating or cooling delivered.
  • Did you know replacement windows have very low return on investment?
    Windows in most homes have great SHGC
    Code requirements
  • Flash and dash nightmares, expensive windows improperly flashed and air sealed, a builder grade Trane, mention NASA
  • Dramatically different from just a few years ago. Maybe different from the last home you built.
  • There is a spray foam company that doesn’t seal around windows and doors intentionally so there is ventilation
  • More than AHRI matching standards are required!
  • We don’t benefit from advising you to use more expensive equipment
  • $10k in initial energy efficient costs results in $37.70 in additional mortgage costs
  • Smaller units mean less airflow needs to be distributed to the building/rooms – air balancing is mandatory especially with 4” runs to inside rooms – we cannot let them steal air.
    The problem with cold rooms and hot rooms will become more apparent in energy efficient buildings as will the need to air balance.
    When ice is below freezing and it absorbs heat, the temperature rises until it reaches 32F which is the melting point of ice. At 32F it absorbs a lot of heat, the temperature doesn’t change, and instead it just melts. The amount of heat required to melt ice is called the Latent Heat of Fusion and it is 143 btu’s/lb. 1 ton of ice = 2000lbs x 143btuslb = 286000 btus/24hours = 11917 btus/hr or rounded off to 12000btus/hr.
    Once ice is melted is only takes 1 btu/lb to raise the temperature 1F. It only takes 212 -32 = 180btus.
  • 57% of 36kHeating Btus = CFM x Delta T x 1.08Cooling Btus = CFM x Delta HT x 4.5
    AHRI ratings are done with indoor dry bulb temps of 80F and indoor wet bulbs of 67F. ACCA recommends using indoor design temp dry bulb of 75F and 50%RH
    It is harder to cool cooler air than warm. 75F air is harder to cool than 80F.
    AHRI uses 95F outside and ACCA uses 93 for Decatur. It is harder to dump hot air outside when it is hotter outside.
    Manual S is mandatory!!!
  • What about oversized, cheap, low SEER units?
  • This unit is pulling unfiltered, hot and humid air directly into the system. This kills the efficiency as well as being incredibly unhealthy.
  • Raise your hands if you have had a duct blaster test performed this year?
  • We want you to get involved. Quality comes not from inspection but from improvement of the process!
  • ACCA Manual J Handout
  • See The Synergy Airflow and Ventilation LLC HVAC Design Questionnaire. AHRI ratings are done with indoor dry bulb temps of 80F and indoor wet bulbs of 67F. ACCA recommends using indoor design temp dry bulb of 75F and 50%RH
    It is harder to cool cooler air than warm. 75F air is harder to cool than 80F.
    AHRI uses 95F outside and ACCA uses 93 for Decatur. It is harder to dump hot air outside when it is hotter outside.
    Manual S is mandatory!!!
  • Do you think it is a good idea to have your HVAC contractor perform your HVAC sizing and design? It is very easy to back into the load/equipment that you want to sell
  • Most energy programs advise you to set back your thermostat several degrees. What happens when you setback an oversized unit? It starts and stops more, humidity rises, comfort decreases, and energy savings doesn’t happen
  • Basements are tricky!!!
  • If a load is decreased due to better insulation, better windows, etc. understand that the sensible load decreases but the latent load stays the same.
  • Fresh air ventilation not properly designed and installed can increase latent loads
  • We will talk about dip switches and speed taps later
  • Manual J’s are easy, Manual D’s are hard! We will discuss static pressure shortly.
  • Run from these contractors!
  • Thumb’s are great but they are not good at sizing HVAC systems.
  • Can you tell me how you balance a spider system?
  • Check out the Energy Star V3 HVAC Guidelines
  • How do you know?
  • See one of our HVAC designs. Tell the story of learning it! I honestly cant ever remember talking about friction rates in my first two HVAC design classes….Crying about it leaving the hotel of my second class…Drawing houses out….cabintet and closet CAD systems…HVAC design….
  • 2 stage units and variable speed units. Basements are close to 2000sf per ton but need dehumidification.
  • The location of the outside units, the air handlers, the refrigerant lines, the electrical service, sound and visual concerns, conditioned or unconditioned space
  • The tail that wags the dog….
  • We can so you the Btu difference in each case
  • Understand and confirm the code requirements for encapsulated attics and conditioned crawlspaces with your local building inspector. The City of Huntsville Building Department requires an engineering stamp for conditioned crawlspaces. They want the airflow confirmed into and out of crawlspaces but they don’t require it for the main body of the home???
  • Conditioned crawlspaces help reduce moisture issues, increase comfort, etc
  • Most people assume the rated R-values are the installation R-values.
  • I recommend them!!!
  • Can’t we all just get along?
  • PSC vs ECM
  • For more info on zoning see me after the meeting
  • Laminar flow is the term for air in elbows
  • See the attached handout! Have you ever seen a balancing damper? To avoid air balancing we some contractors use all of the same size duct!
  • It can’t be done
  • Designing to TEL means most of the other ducts will be oversized
  • It is impossible to assume the same TEL on a rancher vs etc
  • Slides 105 and 106
  • Duct diameter round metal or kinked flex duct?
  • The ductulator example shows that with flex duct at .1 IWC and a 4 ton system with 1600cfm the return size is 19”. If we use the 0.5IWC fan from the previous calculation with a 0.042 FR we get a 23” return duct.
  • The local supply house does not stock 4” duct! Most HVAC contractors don’t use balancing dampers? Almost none measure flow with a flowhood and air balance.
  • I learned this the hard way in the cellulose business!!!
  • Duct cleaning is often a “shady” business
  • They restrict airflow at the return and cause the ducts to pull in air from leaks in the duct system. Many homeowners will put filters wherever they can and fail to change them.
  • See Recalculating the Filter Pressure Drop
  • We often use transfer grilles to prevent having to use multiple filters.
  • Step1 - Airtight construction using spray foam insulation. Step 2 - Fresh air ventilation. Step 4 - Pressure balancing
  • What if the return is completely blocked by a piece of furniture?
  • We find this on numerous systems. If you don’t open and inspect the air handler and you don’t static pressure test, how would you ever find this?
  • Do not let the installer decide on the day of the install
  • Crawlspace penetrations for package units are rarely properly sealed
  • The areas where package unit’s ducts enter the crawlspace are areas of major leakage. Notice the fiberglass batt has turned gray from filtering dust from the leaking return duct.
  • We recommend round metal supply trunks, flexduct branch ducts, and flexduct returns. We can bid out any type of ductwork you prefer.
  • The lifetime is better with flex when it is installed in the conditioned space
  • We saved this building owner $1000 per month in utility bills by installing foam in the attic over this “drop ceiling”
  • This home was built by a builder that touted “green” homes. They are no longer in business. Once this is sheet-rocked, how can it ever be accessed to be repaired?
  • This my personal house
  • A variable speed fan with a 2 stage compressor is mandatory for proper zoning. Single speed airhandlers with only 2 zones send all of the air into a single zone when only one zone is calling. Zoning should only be used with variable speed fans.
  • Notice the ICF foundation without properly insulating the rim joists/band joists
  • How about comfort in bedrooms
  • There are numerous HVAC systems prematurely failing due to duct sealing.
  • Notice the static is 1.04.
  • Notice the static is 1.04.
  • Good designs use ultralow energy! Bad designs use mucho energy!
  • Probably too much info
  • Two stage variable speed units offer added dehumidification and comfort. However we rarely find that they have been adjusted from the factory settings.
  • Freon should not be added more than every 5 years. Demand the TEL of the compressor line set is calculated
  • Make your HVAC technician explains their measurements and how they calculated the refrigerant charging
  • How HVAC systems perform on paper are much different than how they perform in real life applications
  • A flowhood is mandatory for air-balancing
  • If we decrease the duct size, we increase velocity and velocity means noise
  • Old school velocity and diffuser throw guidelines are no longer needed in low load high efficiency homes
  • Remember, you are pulling in the air from somewhere unless you provide fresh air ventilation. People and appliances affect the internal heat gain calculations.
  • I personally believe variable speed compressors are going to steal sales from geothermal units.
  • At this point, does it matter if the insulation is good or bad or if the windows are good or bad??? Geothermal units come up to 6 tons versus 5 tons for conventionally units.
  • Step 4 - Properly Sized, Designed, Installed, and Commissioned HVAC Systems

    1. 1. Step 4 Properly Sized, Designed, Installed, and Commissioned Heating, Ventilation, and Air Conditioning (HVAC) Systems •1
    2. 2. The 7 Steps of Building a Synergy Home 1. Airtight Construction 2. Fresh Air Ventilation 3. Improved Thermal Systems 4. Properly Sized, Designed, Installed, and Commissioned HVAC Systems 5. Pressure Balanced 6. Moisture Managed 7. Combustion Safety Passing a blower door test and a duct leakage test does not make an energy efficient home! •2
    3. 3. Proper HVAC sizing, design, installation, and commissioning in new residential construction is mostly ignored and rarely achieved. • Sadly, this is true in many homes advertised as “energy efficient” or “green”. • HVAC in new home construction is more than just a machine blowing cold air or hot air! • What does HVAC mean to you? •3
    4. 4. A few things about the HVAC industry : • It is extremely price driven. Many profitable HVAC contractors refuse to bid on new construction, especially production homes. • There is an extremely low threshold for entry. Many installers work a couple of years, get their HVAC license, and go into business and steal their old employer’s customers by lowering the price. • The local HVAC supply house is under pressure to make sales and will practically sell to anyone. • There are relatively few newcomers from other industries. • Most installation practices have been passed down over the years despite enormous changes in homes and equipment. • Continuing education is minimal. • International Residential Codes are not followed and not enforced. • Accepted best practices from the Air Conditioning Contractors of America (ACCA) are not followed. • Is it just me or does almost everyone have a relative or friend in the HVAC business that is going to give them a deal? • Most contractors are too busy staying in business to change for the better! •4
    5. 5. Studies show that the average HVAC system delivers only 57% of the rated British Thermal Units (BTUs) into a home. • Where is the other 43%? • Would this be acceptable with plumbing? Any other product? • A duct tightness test is not the solution. •5
    6. 6. Most people…. Want/Specify • Granite countertops • Cabinets • Appliances • Flooring • Landscaping • Additional square footage • Interior finishes and other cosmetic items • Etc Ignore/Assume • Insulation • Air Sealing • Windows • HVAC Sizing, Design, Installation, and Commissioning • Crawlspace / Moisture / Foundation issues • Etc •6
    7. 7. Some people attempt to build an energy efficient home by spending extra money on products that are improperly installed and/or integrated. Examples include: • Spray foam. • High quality windows. • High SEER rated HVAC units/geothermal units. • Special air filtration systems. • Radiant barriers. • You name it and people have tried it!! •7
    8. 8. Many homes including those marketed as “energy efficient” or “green” are experiencing: • Major comfort issues. • Indoor air quality issues such as dust, odors, and humidity. • Moisture issues. • Premature failure of equipment specifically HVAC. • Durability issues. • High utility bills. • “Green washing” is a major storm on the horizon. • Are you familiar with the builder that established it’s own energy efficient “haus” program? •8
    9. 9. Let’s consider how homes built today have changed dramatically from how homes were built in the past. •9
    10. 10. 1st Big Change - Insulation • It keeps heat in or out. • By keeping heat in or out, it prevents wall cavities from drying out if they get wet. • In general, insulation itself is much better. • Old uninsulated homes are durable but not very comfortable. • Many new insulated homes are more comfortable but not very durable. • How does better insulation, installed incorrectly, affect your home, and specifically, your HVAC system? Who knows? • How does better insulation, installed correctly, affect your home and specifically, your HVAC system? We Know! • Passing local code requirements and a blower door test does not mean your home is energy efficient. • You need an insulation and building science professional! •10
    11. 11. 2nd Big Change – Fresh Air Ventilation is Required • Numerous improved building products and air-sealing decreases air changes/ventilation. • Less air changes/ventilation means less dilution of interior pollutants. • Chimneys and exhaust fans compete for available air. • The elimination of chimneys & introduction of house-vented fireplaces. • The introduction of commercial grade gas cooktops and exhaust systems. •11
    12. 12. 3rd Big Change – Air Balancing and Pressure Balancing is Required • Tighter systems are easier to pressurize or depressurize. • Leaky ducts, extensive supplies and limited returns cause pressurization and depressurization problems. • Transfer grilles/jumper ducts are mandatory in all bedrooms. • Undersized ducts that pass duct leakage testing are a major storm on the horizon. •12
    13. 13. Today’s homes are interactive systems that are made up of multiple products, and most of all, people. • When just one product or system is changed, the other products and systems must be changed or adjusted to keep the system in balance. • Houses are oftentimes foamed after the HVAC is installed assuming traditional fiberglass insulation is going to be used. •13
    14. 14. Houses must be assembled onsite with numerous parts and pieces and subcontractors. • HVAC systems are more than just the box and it’s SEER rating. • If your car or truck had to be assembled at the dealership instead of the factory, don’t you think your car dealer would become much more important? •14
    15. 15. “Synergy” is defined as the cooperative interaction among multiple systems so that their combined effect is greater than the sum of their individual effects. •15
    16. 16. “Synergy” is what sets us apart from other companies! • HVAC design, sizing, bidding, installation inspection, and commissioning. • Spray foam installation and air sealing. • Closed crawlspace construction services and moisture management. • Energy auditing / DET Testing. • Building science consulting. • Consider insulation as your defense and HVAC as your offense. •16
    17. 17. We don’t sell HVAC equipment. • We sell comfort solutions! • We are 3rd Party design specialists guaranteeing energy efficiency, comfort, durability, and improved indoor air quality (IAQ). • There is not a conflict of interest in recommending higher priced equipment and installs. We have no monetary gain involved. • All for the same price or only slightly more than you were going to spend anyway on the extra tonnage. • HVAC companies can spend more time focusing on running the business instead of sizing and designing systems. • We eliminate/reduce callbacks. • We increase customer satisfaction. • We increase service revenue. • We increase installation revenue. • We limit liability. • We make it easier on everyone involved. •17
    18. 18. Energy efficiency has never been so inexpensive to finance. A 30 year mortgage at 4% costs approximately $3.77 per $1000. • Consider $20,000 extra costs for foam insulation and upgraded HVAC. • Is there an issue if the house is $399,000 instead of $379,000? • $20000/1000 x 3.77 = $75.40 each month extra on your mortgage! • You pay an extra $75.40 per month on your mortgage and get $200 in approximate utility bill savings. • Sounds pretty good so why isn’t everyone doing it? •18
    19. 19. A ton of air conditioning is roughly 12000 British thermal units (Btu’s). • Typically, we need between 350-400 cubic feet per minute (cfm) of air per ton. • The slower the better in Alabama. •19
    20. 20. Seasonal Energy Efficiency Rating (SEER) is most commonly used for evaluating the efficiency of an AC. • SEER only applies to cooling power and is the ratio of the cooling output based over the cooling season. • SEER = BTUs / Watt Hours • Ranges from around 8 to 30. • In a perfect 13 SEER 3 ton System: 36000 BTU / 2769 watts = 13 SEER • In a typical 3 ton System at 57%: 21000 BTU / 2769 watts = 7.8 SEER • Energy Efficiency Ratio (EER) gives you a better idea of how your unit will do in varying climates. •20
    21. 21. Installing oversized, high SEER rated equipment is not energy efficient. • The Federal Government has falsely led homeowners to believe that high SEER rated units with a yellow Energy Star sticker guarantees energy efficiency. • We have wasted millions of tax dollars subsidizing homeowners for “equipment only” upgrades while ignoring the system as a whole. • Read “Bigger Is Not Better” Articles. •21
    22. 22. In existing homes, whatever tonnage the home got originally, will more than likely, be the tonnage the home gets when the system is replaced. • What if the original system was oversized? • What if the ducts were improperly sized and installed? • What if new windows have been installed? • What if air sealing and insulation has been added? • New units have more restrictive coils. •22
    23. 23. Rarely is the ductwork considered. Changing out the unit without considering the ductwork is like getting a heart transplant and not repairing your circulatory system or installing a brand new motor in an old jalopy. •23
    24. 24. The HVAC unit in this home was replaced with an Energy Star 16 SEER unit without repairing or replacing the ductwork. •24
    25. 25. Most homeowners do not plan or budget for an HVAC unit replacement. • Units often fail during the hottest or coldest periods of the year. • The homeowner wants heating or cooling restored right away and doesn’t want to wait, much less pay, for proper system design and duct remediation. •25
    26. 26. Check out www.escore.com for rebate programs and financing so you get a “Synergized” existing home. •26
    27. 27. You need to understand… • Q = U x A x Delta T (QUAT) • The importance of Manual J, S, D, and T. • The importance of air flow. • The difference in single speed air handlers and variable speed air handlers. • The difference between single stage, two stage, and variable speed condensers. • The extreme importance of static pressure and pressure drops. • The myth of sizing supply ducts with 0.1IWC and return ducts with 0.08IWC. • Measuring output is the only assurance! •27
    28. 28. What is a Manual J Load Calculation? • It is a complex calculation that determines the heating and cooling requirements of individual rooms as well as the heating and cooling requirements of the entire house. • What size unit do we use if it calls for a 3.1 tons? • How much airflow is needed? •28
    29. 29. Manual J Calculations consider • Q = U Value x Area X Delta T • Indoor design temperatures of 70 degrees for winter and 75 degrees for summer. • Outdoor design temperatures based on 1% of the of the peak / worst case conditions for your area. Decatur is 93 summer and 16 winter. 24 hours x 365 days x 1% = 87.6 hours. • Delta T for cooling is 93-75 = 18 Delta T for heating is 70-16 = 54 • The construction of the exterior walls. • Slab or crawlspace construction. • Vented or encapsulated crawlspace. • Vented or encapsulated attic. • The orientation of the house. East or West is worse than North or South. • The type, number, size, orientation, U-Value, SHGC, and shading of the windows as well as the interior window treatments. 30/30 Rule! • R-Values. • Infiltration rates and ventilation rates. • The number of people and appliances.200latent/230Sens/500WD/1200K • The type of equipment. • The location of the ductwork. •29
    30. 30. An accurate Manual J Load Calculation takes time and requires a lot of information. •30
    31. 31. Garbage in = Garbage out • “Short forms” are inaccurate. • “Block” load calculations are inaccurate. • Why bother? •31
    32. 32. It is almost always more efficient and more comfortable for your air conditioner to be sized correctly so that it runs continuously or almost continuously during the hottest months of the year. • What happens when you follow the advice from the article in the newspaper / local utility company and you set your thermostat a few degrees higher in the summertime? • On one of the hottest days of the year, check and see if your unit is operating continually or almost continually. •32
    33. 33. When your HVAC system is not operating it is not dehumidifying. • The longer the system runs, the colder the interior coil becomes, and the better the system works. • Cool, drier air is much more comfortable than cold, clammy air. •33
    34. 34. Every time your HVAC system “cranks up” it is costing you money. • Watt draw at initial start up is very high and efficiencies are very low. • Do your lights blink or flicker when your unit starts up? • Do you hear it “crank up”? • Do you get short, cold blasts from your air conditioner and then it cuts off? • Can you hear the air whistle as it leaves or enters your registers? • The average life of an HVAC system is less than 9 years. •34
    35. 35. What is a Manual S Calculation? • A Manual S helps select the proper equipment by matching the specific equipment to the Manual J Load Calculation’s sensible and latent load. • Understand that in our area we size loads to the cooling load not the heating load. •35
    36. 36. Sensible cooling is actual cooling/coolness you feel. • This is measured by a drop in dry bulb temperature. • Latent is dehumidification. • If we only provide sensible cooling the relative humidity actually goes up. • We assume a sensible heat ratio of 70/30. •36
    37. 37. We reduce internal latent loads by • Proper air sealing of penetrations. Air must be contained before it is controlled. • The use of spray foam. • Closed crawlspace construction with proper drainage and dehumidification. • Properly exhausted kitchen and bathroom fans. • Properly exhausted clothes dryers. • Encapsulating the attic with spray foam. • Not necessarily by using fresh air ventilation. •37
    38. 38. Most equipment manufacturers have similar quality equipment. Chevy is to Ford is to Dodge is to Toyota. • Manufacturers often produce more than one brand. Trane/American Standard. Carrier/Bryant. • The field installation is much more important than the name brand of the equipment. Many people don’t seem to mind pay extra for a Trane. • HVAC equipment must work differently in hot, humid areas as compared to hot, dry areas. •38
    39. 39. What is a Manual D Calculation? • Manual D sizes ducts for the proper delivery and return of the calculated air flow based on the size of the blower that comes with the specific equipment. •39
    40. 40. The IRC Code requires Manual J,S, D, & T’s! Manufacturers require them! •40
    41. 41. The Alabama Board of Heating, Air Conditioning, and Refrigeration Contractors require them! •41
    42. 42. The Energy Star for New Homes Program requires them! Consult the “Energy Star for New Homes Version 3 HVAC Checklist”. •42
    43. 43. Many of the largest HVAC companies with all the brand new trucks and advertising don’t perform Manual J, S, D, and T’s. • Many HVAC contractors simply don’t believe in Manual J, S, D, and T’s. • Manual J’s are easily backed into to get the size you want if you use incorrect data. •43
    44. 44. So why don’t most HVAC contractors perform Manual J’s, Manual S’s and Manual D’s? • They never had to do them before. • It is a very difficult process to master. • Many HVAC companies are in the business of selling and installing equipment. Multiple units can be installed in the same amount of time it takes to design and install a total system properly. • More tonnage means higher sales revenues. •44
    45. 45. The #1 Reason…. •This section of the code is not enforced! •45
    46. 46. What does a building code inspector “inspect for” in the absence of a Manual J, S, D, and T? • What does a mechanical inspection involve if it doesn’t involve enforcing properly sized, properly designed, and properly installed HVAC systems? Is it just about correct clearances and electrical connections? • If the indoor and outdoor unit are AHRI matched but the unit is oversized and the ducts are undersized does it matter? •46
    47. 47. How did we get here? • Am I the only one that this doesn’t make sense to? • Does anyone besides me find it strange that a jurisdiction requires an Engineer’s stamp stating how much air is going into a conditioned crawlspace but we don’t know how much air is going into the house? •47
    48. 48. Can we blame an HVAC contractor for over-sizing? • Many reputable HVAC contractors have never had control over the other construction details and subcontractors that affect load calculations. • We have an uneven playing field where the guys that do the right thing are oftentimes penalized by not getting business. •48
    49. 49. When is the contractor most at risk for construction defects? • Code compliancy is not achieved. (Regardless of whether or not the code official passed it) • The contract is not complied with. • Standard practice is not accomplished. • The manufacturer’s specifications are not followed. • Reasonable consumer expectation is not met. • When certifications and qualifications for green building or energy efficient construction methods are advertised but not met. This is called “green washing”. • Negligence. • Fraud and misrepresentation. •49
    50. 50. Some HVAC contractors provide Manual J, S,D, and T’s. • Most are inaccurate due to the lack of understanding of thermal boundaries, proper location and levels of insulation, available static pressure, fresh air ventilation, air sealing, moving the system into the conditioned space, etc. • The lack of control still leads to oversizing. • Why not get an objective HVAC sizing and design from a professional? • Let us do it while you concentrate on the specifics of running your business. •50
    51. 51. Many HVAC contractors • Size the HVAC unit by the square footage. • Run flex duct from the supply plenum to the outside of the room in any way possible. Spider boxes are becoming popular in the production home market. • Install a single undersized return anywhere you can fit it. • Install the cheapest unit available. • Solder the line-set. • Release the refrigerant charge. • Turn it on, look at the gauges, and make sure it blows cold air. •51
    52. 52. As a rule of thumb, how many square feet per ton should you figure? •52
    53. 53. What does the typical HVAC contractor charge per ton of HVAC? • $1500? • $2000? • What do you pay? • What do you charge per square foot to build a home? • Should we buy automobiles by the pound? •53
    54. 54. How many HVAC companies will price your HVAC system over the phone without even looking at it? • A 2000sf house / 500 x $1500 = $6000. • If you are really lucky they might give you the 5 ton unit sitting in the warehouse for the same price as the 4 ton unit. •54
    55. 55. If the ductwork is not specifically priced into the job then you can almost be assured that you are getting the bare minimum. •55
    56. 56. The infamous spider box. In the second picture, the unit is way oversized. When the unit kicks on for a short period, how much air goes to each line? How do you control it? Note that these lines feed other spider boxes. •56
    57. 57. The Air Conditioning Contractors of America issued the HVAC Quality Installation Specifications to help address these issues. www.acca.org/quality •57
    58. 58. Do you believe that you are going to be the one person that gets a high performance HVAC system without planning, design, inspecting, and commissioning all for an unbelievably low price? •58
    59. 59. How much heating, cooling, and ventilation do you need if you have framing bypasses, your house leaks, your insulation does not work, you have cheap windows, and your unit is not installed correctly? •59
    60. 60. How much heating, cooling, and ventilation do you need if you build the home perfectly but get a bad ductwork design and installation? •60
    61. 61. How do you know if you don’t size, design, and then test your home and it’s systems? www.WeTestOthersGuess.com •61
    62. 62. The Synergy Airflow and Ventilation LLC HVAC design process. •62
    63. 63. We use Right-Suite Universal because it is simply the best! We are simply the best at using it! •63
    64. 64. See “The HVAC Design Customer Questionnaire” and our full size HVAC Design example. • We provide you with the proper documentation and all of the inputs for our calculations. • We can show how different construction details affect your load in order to decide whether or not it is cost effective. • Any questions on construction details? •64
    65. 65. We average approximately 1200 sf per ton which oftentimes results in reducing your HVAC equipment by 50% or more. • Oftentimes, we eliminate several units in large homes. • Basements average close to 2000 sf per ton. • Bonus room HVAC sizing is greatly reduced due to the use of foam. • Shift additional tonnage to better equipment and better installation. •65
    66. 66. It is imperative you plan and design the actual location of the HVAC equipment and duct system. • It cannot be an afterthought if it is to be done correctly. •66
    67. 67. The IRC specifies maximum distances from the crawlspace or attic access to the equipment. The location, the headroom, walkways, etc, help to determine this. Always confirm with your building inspector. •67
    68. 68. To most code officials, the ease of inspecting and servicing an HVAC system is more important than proper location of the unit. • We recommend multiple crawlspace access doors! • Let’s discuss this! • We need the input of code officials! •68
    69. 69. Many house-plans/blueprints do not provide space for the HVAC system, especially the returns. •69
    70. 70. What’s wrong? •70
    71. 71. These ducts were crammed into the attic directly under the roof decking where they have large conduction gains. Notice the ducts inside of foam on the right but severely pinched. •71
    72. 72. We meet with you and review your blueprints extensively, applying the “Seven Steps of Building a Synergy Home”. • We discuss your goals and most importantly, your budget, so we can recommend the most cost effective solutions that offer the most return on investment. •72
    73. 73. We draw out the house and locate the “thermal building envelope” using our years of experience in the insulation business. • We have to contain air before we control it! • Encapsulated attics using spray foam and conditioned crawlspace homes have very different building envelopes than traditionally insulated and vented homes. • We start with a great defense/insulation and add a great offense/HVAC. •73
    74. 74. Why would you ever install your HVAC system in a 140 degree vented attic or a 20 degree vented crawlspace? •74
    75. 75. Why not move the entire system into the conditioned space? We can show you how big of a difference it makes! •75
    76. 76. Traditional fiberglass insulation in a crawlspace or bonus room floor does not work due to the fact that it must be in complete contact with the subfloor. Understand that R19 fiberglass is not R19 foam. The lack of understanding the building thermal envelope is significant in home performance! •76
    77. 77. R-values for traditional insulation such as fiberglass batts entered into load calculations are assumed to be correct. We know from testing that most R-values in real world applications are much less. This R13 is not R13. 4” of foam when 6” was quoted. •77
    78. 78. Heat pumps are ideal for foam homes and encapsulated crawlspaces. They have gotten a bad reputation for comfort due to.. • Blowing cold air in the winter air due to the fact they are single speed and oversized. • Blowing cold air in winter because the ducts are located in unconditioned areas. • Improper insulation and air sealing. • Cheap windows. •78
    79. 79. In heating mode when the unit doesn’t run except for short periods… • The warm air in the ductwork gets cold when the unit turns off. • When the unit starts back up you are “blasted” with this cold air. • Combined with “cold spots” throughout the home, comfort is greatly affected. •79
    80. 80. Heat Pumps… • Eliminate any problems associated with gas combustion. • Require specific occupant behavior. • Warm homes slowly but maintain it with even temperatures. • Lose little efficiency in wintertime when the temperature drops and lose efficiency in the summertime when the temperature rises. • “Kick in” the emergency heat strips when you turn up your thermostat by more than 2 degrees and this costs $$$. • Require an exterior thermostat that “locks out” electric heat strip use until the balance point is reached. •80
    81. 81. Gas furnaces must be direct vent / sealed combustion units when installed in encapsulated attics or crawlspaces. Low efficiency B vented / atmospherically vented gas furnaces and water heaters cannot be installed in encapsulated crawlspace or attics. They are dangerous and expensive to operate and should be outlawed. Have you ever stopped to consider why most gas companies give them away for free if you will use one? •81
    82. 82. After we move the ducts into a well insulated and air sealed conditioned space, we focus on airflow by designing your system using realistic static pressures and friction rates. •82
    83. 83. The static pressure of your HVAC system is the equivalent to your blood pressure. •83
    84. 84. Air weighs approximately 0.075lbs per square foot. • 1 ton of HVAC requires approximately 350-400 cubic feet per minute (cfm). • 4 tons x 400 cfm x 0.075lbs x 60 minutes = 7200 lbs of air! •84
    85. 85. Static pressure is measured in inches of water column (IWC) or Pascals. • IWC is an HVAC industry measurement. • Pascals is a home performance industry measurement. • 1 IWC = 250 Pascals •85
    86. 86. Single speed air handlers (PSC’s) are typically rated at 0.5 inches of water column (IWC). • Variable speed fans (ECM’s) are rated at 0.8 IWC and are often able to ramp up to over 1.0 IWC if needed (not recommended). •86
    87. 87. A .5 IWC single speed fan is like a 40 mph single speed car • Put it in gear and it attempts to go 0.5 IWC (40mph) even if you are just going a few blocks or you are just backing out of the driveway. • It puts tremendous wear and tear on the mechanical parts when it starts up because it doesn’t ramp up slowly or ramp down like a variable speed fan does. • It only goes 40 mph and sometimes much less when going up a hill (restricted ducts). •87
    88. 88. Why is a 0.8 IWC variable speed air handler necessary? • Duct systems have increased in size total length due to larger homes. • Fins in “energy efficient” coils are more closely packed together and thus restrict airflow. • Filters, and restrictive, undersized ducts require fans with higher rated static pressure. • It starts up slowly and uses less energy initially. • A single speed fan that is not moving the proper amount of air cannot just work harder. • It is able to ramp up and move the proper amount of air or ramp down and dehumidify. • Variable speed fans should not be used in place of poor duct design because it increases the fan watt draw. • Zoning is rarely needed in today’s homes but when it is a variable speed fan is mandatory for zoning. • Don’t let the replacement cost of a variable speed motor over a single speed motor keep you from buying one!!! •88
    89. 89. Everything the air passes through in your duct system such as a restrictive filter has an impact on how much comes out on the other end. • Available static pressure (ASP) is the pressure remaining that can be used to design a duct system after all of the external components have been deducted. • Available static pressure = static pressure of the blower – pressure drops •89
    90. 90. Issues affecting the available static pressure (ASP) of a system • The static pressure rating of the fan motor. It is usually rated as a 0.5 IWC or a 0.8 IWC. • Pressure drops over coils, filters, supply registers, return grilles, and balancing dampers. • Pressure drops due to the internal friction of the duct material used. • The total effective length (TEL) of the duct system. • Fittings and restrictions on the duct work. •90
    91. 91. Pressure loss assumptions over the evaporator coil. • During design we assume a pressure loss of 50% for the coil and filter of a heat pump. • We use percentages because most manufacturer’s data is inaccurate. • Many systems are tested and rated at unrealistically low watt draws in order to make them appear super-efficient. •91
    92. 92. Several manufacturers spec’s for the coil drop on a heat-pump. Note the 5 ton Carrier listed at CAPV060 has a coil drop of .407 IWC. •92
    93. 93. In addition to assuming a 50% pressure drop across the coil and filter. We also assume the following pressure drops… • Balancing dampers = .03 IWC • Supply grilles = .03 IWC • Return grilles = .03 IWC •93
    94. 94. Realistic static pressure drops are mandatory for correct duct sizing. This is the static pressure screen from our HVAC design software. •94
    95. 95. Available Static Pressure Calculation for a Variable Speed Fan • Total Rated Pressure of Variable Speed Fan 0.8 IWC • Pressure drop of coil and filter (50%) (0.40 IWC) • Pressure drop of supply register (0.03 IWC) • Pressure drop of return grille (0.03 IWC) • Pressure drop of balancing damper (0.03 IWC) • Equals .31 IWC of available static pressure which is very good! •95
    96. 96. Available Static Pressure Calculation for a Single Speed Fan • Total Rated Pressure of Single Speed Fan 0.50 IWC • Pressure drop of coil and filter (50%) (0.25 IWC) • Pressure drop of supply register (0.03 IWC) • Pressure drop of return grille (0.03 IWC) • Pressure drop of balancing damper (0.03 IWC) • Equals .16 IWC of available static pressure which is Ok. •96
    97. 97. Available Static Pressure Calculation with the manufacturer’s published coil drop instead of a percentage. • Total Rated Pressure of Single Speed Fan 0.50 IWC • Pressure drop of coil (0.407 IWC) • Pressure drop of supply register (0.03 IWC) • Pressure drop of return grille (0.03 IWC) • Pressure drop of balancing damper (0.03 IWC) • Equals .003 IWC of available static pressure for the entire duct system. This is really bad when you add in a restrictive filter! •97
    98. 98. An Available Static Pressure (ASP) of .31 IWC is much better than .16 IWC. • How do we design a system with only .003 IWC for the entire system? • It can’t be done but it is being done everyday. • Most HVAC companies design duct systems incorrectly according to available static pressure instead of friction rates. • Friction rates convert available static pressure into 100 ft. •98
    99. 99. See our handout on “Static Pressure, Friction Rate, and Total Effective Length”. • Friction Rate = (ASP x 100)/TEL • ASP = Available static pressure • TEL = Total effective length • The Total Equivalent Length (TEL) is the sum of the longest measured supply register to the longest return grille plus the equivalent length of the fittings. • Many of our systems have TEL of over 400 ft. •99
    100. 100. An equivalent length of a fitting can be looked up in the ACCA Manual. It converts a particular fitting such as an elbow to an equivalent length of straight duct. Note that a duct at the end of a trunk line has a different equivalent length of the same size duct with multiple branches downstream. •100
    101. 101. Friction Rate = (ASP x 100)/TEL • 0.8 IWC Variable Speed Fan FR = (.31 x 100) / 384 = .081 • 0.5 IWC Single Speed Fan FR = (.16 x 100) / 384 = .042 • Most HVAC companies use 0.1 IWC standard for supply ducts and 0.08 IWC for returns. Could this be a problem? •101
    102. 102. A ductulator requires 2 specific things to calculate the duct diameter: • Airflow in cfm for each room. • Friction rate – how often do you calculate the friction rate??? •102
    103. 103. Ductulators are not accurate if • The friction rate is wrong due to using arbitrary numbers such as 0.1 IWC for supply ducts and 0.8 IWC for return ducts. From our earlier calculation we found the friction rate to be .042 IWC which is half of what is typically assumed. • The cfm of each room has not been calculated by performing a Manual J correctly. • In other words, you cannot just pick up a ductulator and look up 150cfm and get the right size of duct. •103
    104. 104. What happens if you calculate the proper friction rate and you know the proper airflow in cfm and you determine you need a 4” duct, but instead, you use a 5” duct, or worse, a 6” duct? •104
    105. 105. As we build super energy efficient homes and reduce the tonnage and specifically the airflow, it is imperative that we get the right amount of airflow supplied to and returned from each individual room. •105
    106. 106. What about contractors that use the same size branch ducts for every room in the house? You cannot damper an 8” duct down to deliver what a 6” duct delivers. Especially, if dampers are not even installed. •106
    107. 107. Without the knowledge needed to perform proper Manual J, S, D, and T’s, most contractors rely on extra tonnage in order to provide additional arbitrarily determined airflow. • For example, use a 3 ton system with a 0.5 IWC fan that should move approximately 1200 cfm of air but due to pressure drops and undersized ductwork it moves 2 tons or approximately 800 cfm of air or less. •107
    108. 108. Our goal is to maximize the total available static pressure by the following: • Using a higher rated fan such as a 0.8 IWC rated variable speed fan. • Minimizing pressure drops. • Minimizing the total effective length of the duct system. • (Increase) FR = (Increase)ASP x 100 / (Decrease)TEL •108
    109. 109. We have learned that most homeowners will pay extra for… • Single stage compressors with variable speed air handlers. • 2 stage compressors with variable speed air handlers. • Variable speed compressors with variable speed air handlers. • Most homeowners are never told about optional upgrades and are very upset when they find out they were not even offered. •109
    110. 110. 2 Stage / Variable Speed Compressors are “game changers” in a diverse climate like Alabama’s! • 2 stage systems - 1st Stage is 60% to 70%. 2nd Stage is the remainder. • Variable speed systems – 1st stage is approximately 40%. 2nd stage is approximately 40% to 70%. 3rd stage is the remainder. • SEER ratings are calculated for the total output and are much higher on lower stages. • Communicating Thermostats are great. • Dehumidification and comfort is greatly increased. • Higher upfront cost with strong return on investment that provide long-term savings. •110
    111. 111. What happens to the best designed, most advanced unit when the interior coil is filthy due to operation during construction? •111
    112. 112. Wouldn’t it be a good idea to have it checked before you begin operating it? • Coils that appear clean are often clogged with sheetrock dust. • Has your HVAC company ever offered to clean your interior coil? • Your return side of the coil is difficult to access. • Furnaces are almost impossible to access. • How do you build a removable panel that allows access to the return side of the coil? •112
    113. 113. We simply recommend that you never operate your HVAC system during construction. •113
    114. 114. Make sure the registers are covered during construction and that the cut-outs are removed from the crawlspace so that they cannot attract termites. •114
    115. 115. Do not waste money on duct cleaning services. Whatever caused them to get dirty in the first place will most often cause them to get dirty again. Simply clean the ducts out with your vacuum cleaner as far as you can reach. •115
    116. 116. An air filter’s main responsibility is to keep the evaporator coil clean. Most filter systems choke airflow and actually contribute to indoor air quality issues. •116
    117. 117. It has been said that more HVAC systems have been killed by Paul Harvey, selling washable, restrictive filters than any other reason. If you have a metal, washable filter, go home and throw it away immediately and replace it with an inexpensive, unrestrictive filter. •117
    118. 118. Lifetime Ecofilter’s are Garbage! •118
    119. 119. Keep in mind that compressors don’t die, they are murdered. 88 Pascals / 250 = .352 IWC •119
    120. 120. Restrictive filters are often the cause of major issues in a duct system. • Most filters are rated at 300 feet per minute (fpm) of air velocity. • Many systems are field-tested with actual velocities of 1000fpm and this greatly increases filter pressure drops and prevents proper filtering of the air. •120
    121. 121. Understand how to recalculate filter pressure drop using Fan Law 2. • Sp2 = SP1 x (CFM2/CFM1)squared • The pressure drop of a filter will increase at more than twice the rate the airflow increases through the filter. •121
    122. 122. Limiting the numbers of filters that need to be changed and centrally locating the filter(s) are important steps to consider. •122
    123. 123. We rarely recommend accessory air cleaners. Building a home in accordance with “The Seven Steps of Building a Synergy Home” helps decrease dust and other contaminants as wells as increase indoor air quality inside the home. •123
    124. 124. Returns need to be properly sized and should never be located in closets even with a louvered door. •124
    125. 125. Notice the interior air handler insulation has pulled loose and is choking the airflow. •125
    126. 126. The placement of the air handler and the individual registers must be considered in order to decrease the length of the duct system. We attempt to centrally locate the air handler in the conditioned space, we “T” the supply trunks, and we reduce return trunk lengths. •126
    127. 127. The location of the outside equipment is influenced by the… • Electrical drops and runs. • The length of the refrigerant runs. • The physical appearance. • Sound. •127
    128. 128. We witness package units experiencing major issues in sprawling homes due to…. • Oversized units. • Single speed, 0.5IWC rated fans. • Extremely long and undersized duct systems. • Single undersized returns with pleated, restrictive filters. • Improper duct sealing and dirty coils. • Improper condensate drainage. • Lack of air balancing. •128
    129. 129. We strongly recommend split systems over package systems. •129
    130. 130. We increase available static pressure by installing ductwork properly. •130
    131. 131. Most ductwork is constructed of round metal, square or rectangular metal, ductboard, and flexduct. •131
    132. 132. Flex duct is not a problem if it is designed, sized, installed, and commissioned properly. • Flex duct is relatively inexpensive and can be very effective. • It is very susceptible to installer error. • It has a shorter lifetime than hard-ducting. • It must be cut to length and properly supported. •132
    133. 133. This is in brand new construction! •133
    134. 134. Proper supply transitions out of the air handler are needed. •134
    135. 135. Do not use framing members as supply ducts. •135
    136. 136. The wall framing is being used as a supply trunk to deliver air from the air- handler located in the attic over the 2nd floor to the 1st floor living space. •136
    137. 137. This installer found it easier to run a 360 instead of cutting it to fit. •137
    138. 138. The holes cut for flex duct must be adequately sized so that the ducts are not pinched. Structural integrity of the framing must also be maintained. •138
    139. 139. This is a two story home on a slab with the 1st floor ducts ran from the attic. Two story slabs are hard to duct properly and are almost impossible to fix once sheetrock is installed. •139
    140. 140. Unplanned ducts under cabinets restrict proper throw from the registers. If a duct needs to be located under a cabinet, plan for it. •140
    141. 141. Decorative wood registers oftentimes severely restrict airflow. Note the extra airflow allowed by the register on the right. •141
    142. 142. Things to consider for proper register placement especially since it is no longer as important to locate HVAC supply registers on exterior walls or near windows to “wash walls” with heating or cooling. • Furniture locations especially beds. • Door swings especially in entrance ways. • Airflow when getting out of the shower or bath. • Built in cabinets. • Line of sight. •142
    143. 143. The AED Assessment shows when zoning is needed. Zoning is rarely needed in a “Synergy” home. Interior window covering and overhangs are important in reducing loads especially in homes facing east and west. •143
    144. 144. Could a severely pinched duct decrease the available static pressure and create premature equipment failure? Do you think conduction gains from the roof could be an issue in the summertime? •144
    145. 145. Notice that there is no “backbox” on the return side. This kills the airflow of this system. •145
    146. 146. “Back boxes” help to reduce turbulence, reduce static pressure, and increase airflow. •146
    147. 147. Do not use framing as return plenums. •147
    148. 148. What happens if you have a supply side leak? • Supply leaks “suck”. • You lose conditioned air to the exterior, the house goes under negative pressure, and you pull in exterior air that is carrying contaminants. • Installing “supply only” ducts in rooms such as a garage creates dangerous situations in homes. •148
    149. 149. Many times we find a “bleeder” that goes unchecked until major issues develop. The blower door will actually help locate major duct leaks. •149
    150. 150. The IRC requires “boots” must be sealed to the building envelope unless located inside the conditioned space. •150
    151. 151. What happens if you have return duct leakage? • Returns leaks cause your home to “blow” or in other words become pressurized. • Returns pull in outside, unconditioned, unhealthy air that carries moisture, radon, odors, dust, insulation, pesticides, etc. •151
    152. 152. In many of the homes we test, as much as 50% of the return air is missing. Where is it going? Was it ever there to begin with? •152
    153. 153. Many coils with low airflow are not freezing up because air handlers are located in 140 degree attics and the leaky return ducts are pulling in hot air that melts the ice. •153
    154. 154. Notice the white insulation has turned gray from filtering air pulled in through this return leak. Return duct leakage is not an issue in an encapsulated attic. •154
    155. 155. Locating the attic access inside the conditioned space in a traditionally vented attic is a bad idea, especially, if is it unsealed and un-insulated. Typically, the return grille is located next the pull-down stairs and it pulls unconditioned air and contaminants from the attic. •155
    156. 156. The net difference in the supply side leakage and the return side leakage causes increased air infiltration in the home. Moving ducts into the conditioned space helps eliminate this. •156
    157. 157. Never close off bedrooms or duct registers. In a foam house, we install jumpers ducts and let the unit run. •157
    158. 158. What happens if you do not have proper return pathways and you close your bedroom doors? • Air that is supplied to the bedroom cannot be returned to the air handler to be reconditioned. • The bedroom becomes pressurized and air is forced out of the room through holes in the envelope. • The main body of the home becomes depressurized and outside air is pulled in from unintended places unless Fresh Air Ventilation Step 2 is provided. • Undercutting doors does not work. • See Step 5 Pressure Balanced. •158
    159. 159. Symptoms of pressure issues • Interior doors close when your unit starts up. • You smell your fireplace when your heating system starts up. • In an effort to become comfortable in your Master bedroom, you adjust the thermostat so that the rest of the home is uncomfortable. • There are markings under and around interior door frames. • Your home is dusty. • Your home has odors. •159
    160. 160. Once your HVAC system is properly designed, sized, and installed….make sure it is airtight. Plumbing is checked for leaks, why are ducts any different? We offer duct-blaster testing because the 2009 IRC requires it unless ducts are installed in the conditioned space. •160
    161. 161. Duct-sealing a properly sized, designed, and installed HVAC system is one of the most cost efficient measures a homeowner can make. •161
    162. 162. Duct-sealing undersized and improperly designed ductwork increases the static pressure and creates additional problems that will eventually lead to premature compressor and fan motor failure. • So why is the new building code along with numerous energy efficiency programs across the nation requiring duct sealing while ignoring proper duct design? • Many systems with extremely high static pressure and extremely low airflow pass duct blaster tests with flying colors. • This is a major storm on the horizon!! •162
    163. 163. We offer static pressure testing along with duct tightness testing. • Few builders and homeowners want it since it is not required by code. • Remember that high static pressure is the equivalent of high blood pressure and it indicates low airflow. •163
    164. 164. Duct tightness standards if ducts are not installed inside of the thermal envelope • 4% of square footage at rough in without AH installed? How accurate can this be??? • 6% of square footage at rough in with AH installed. • 12% of square footage at finish. • 8% of leakage to outside at finish out. •164
    165. 165. Air handlers need to be air-sealed, especially if they are in vented attics or crawlspaces. •165
    166. 166. •166
    167. 167. 71.8 pascals + 234 pascals = 305.8 / 250 = 1.22 IWC. 1.22 IWC should be 0.5 IWC or less. This unit is having a stroke! •167
    168. 168. Smart systems display the static pressure on the thermostat as well as the cubic feet per minute of airflow. Note this unit is at 1.04IWC. The homeowner went with a top of the line unit but did nothing with the poor quality duct system. •168
    169. 169. A typical HVAC system requires approximately 350 - 400 cubic feet per minute of airflow per 1 ton of heating and cooling. For example, 5 tons of heating and cooling requires approximately 5 tons x 350/400 cfm = 1800 - 2000 cfm. •169
    170. 170. Static pressure readings used with manufacturer’s fan data gives us the actual airflow. •170
    171. 171. In units with high static pressure, the rated 1800-2000 cfm of airflow is often found to be around 1000 - 1200 cfm or even lower. Why install a five ton unit incorrectly to get 3 tons or less of airflow? •171
    172. 172. We measure the actual return airflow with a flowhood and compare it to the rated airflow of the system. Note that the flowhood is a symbol of excellence in HVAC contractors. •172
    173. 173. Notice that the delivered cfm of this high SEER unit with bad ductwork is 1957cfm. Smart systems attempt to overcome high static pressure but the watt draw is excessive and eventually the motor will burn out. The air velocity through the ductwork sounded like a jet. •173
    174. 174. Note that when the work of the fan is increased, the watt draw is increased by a factor of 3. Fortunately, when the work of the fan is decreased, the watt draw is decreased by a factor of 3. 3 amps cubed = 27 amps •174
    175. 175. This is too much info but Fan Law 3 3 Amp2 =Amp1 x(CFM2/CFM1) •175
    176. 176. Make sure the dip switches or speed taps are set up properly so that proper airflow is delivered. Most are never adjusted from the original factory settings. •176
    177. 177. Why is low airflow bad? • Comfort requires proper airflow in order to supply and return the right amount of air at the right temperature to the right room. • Premature motor failure. • Cracked heat exchangers – Carbon Monoxide poisoning. • Proper airflow is required before refrigerant is added. • Premature compressor failure – frozen coils often result from low airflow. •177
    178. 178. Refrigerant Charge & Airflow Test Methods • Common but not Recommended  Charge Tests – Pressures – “Beer can cold” suction line – Blowing cold air  Airflow Tests – Nothing • Manufacturers’ Recommendations  Charge Tests – Superheat for non-TXV’s – Subcooling for TXV’s  Airflow Tests – Temperature split to verify airflow •178
    179. 179. Line sets must be properly evacuated and brazed with nitrogen. Does your HVAC contractor even own an evacuation pump? Could this be why so many expansion valves are failing? •179
    180. 180. See Any Issues? •180
    181. 181. Digital gauges must be used to confirm proper charge after proper airflow is confirmed. Analog gauges are inaccurate. •181
    182. 182. Temperature Diagnostics and System Efficiency • Temperature Diagnostics helps demonstrate the advantages of bringing ducts into the conditioned space. • Remember the importance of Q = U Value x Area x Delta T • We measure temperature drops across the “system” along with airflow to determine “system efficiency”. • Measuring temperature drops across the equipment doesn’t tell us much, especially if the airflow is low and the ducts are located in unconditioned spaces. • It is all about “system efficiency” and delivered Btu’s. “Equipment efficiency” measured in a laboratory under ideal conditions is unrealistic to field conditions. • Most of the industry continues to focus on equipment efficiency but we understand that the duct system is most often a greater factor in system efficiency and performance.•182
    183. 183. Measuring Entering Return Grille Temperature •183
    184. 184. Return Duct Loss or Gain Return Duct Temperature Loss = Return Grille Temp – Return Plenum Temperature Heating 70 – 63 = 7 •184
    185. 185. Supply Duct Loss Supply Duct Temperature Loss = Supply Register Temp – Supply Plenum Temperature Cooling 64 – 55 = 9 •185
    186. 186. System Loss or Gain System Loss % = Duct System Temperature Loss/ Equipment Temperature Change Cooling 9 / 18 = 50% Assuming a measured 18 degrees temperature change •186
    187. 187. If you measure the system temperature loss on a mild day or on a summer day in the morning you might get a system delta T of 0. You measure the equipment delta T and you get 20. 0/20 = 0. However, in the afternoon the attic heats up and you have a huge system delta T. Encapsulating the attic and the crawlspace greatly reduces the system delta T. Delta T = temperature difference •187
    188. 188. System Delivered BTU Calculation Heating = Actual CFM x system delta T x 1.08 A 3 unit is found to be moving 850cfm of air and the system delta T is 99.5 – 69.5 = 30. 850 x 30 x 1.08 = 27,540 Delivered BTU Is that good? 30K furnace? 60K furnace? 90k furnace? •188
    189. 189. System Delivered BTU Calculation Cooling = Actual CFM x system delta hT x 4.5 Cooling requires converting the delta T into enthalpy. I will be happy to discuss this later. •189
    190. 190. You can perform a perfect Manual J & D calculation and a perfect installation and still have major comfort issues due to improper airflow unless you air balance and commission the system. •190
    191. 191. We confirm the total system airflow with a flowhood and then we measure airflow and velocity of the individual supply ducts and we balance the system so that each room receives within 10% of the designed airflow at an acceptable velocity. •191
    192. 192. Ducts are sized to the worst case total effective length (TEL) which is the length from the longest and most restrictive supply duct to the longest and most restrictive return duct. Notice the variations in the volume of air required by each room. A Manual J and D are required in order to air balance. •192
    193. 193. Many HVAC companies do not install balancing dampers. Of the companies that do install balancing dampers, they rarely use them to properly balance the system. •193
    194. 194. We rarely have to be concerned with excess velocities. Volume of air in CFM = Area in square feet of the duct X Velocity in feet per minute •194
    195. 195. Recommended Velocity (in fpm) Supply Return Duct Type Rigid Flex Rigid Flex Trunk 700 600 600 600 Branch 600 600 400 400 Outlet Size for Throw Return Grille Face <500 Filter Grille <300 •195
    196. 196. Notice the velocity at this supply register is 1414 feet per minute. It sounds like a jet. •196
    197. 197. 4” x 12” register = 48 sq inches 48/144 = .33 sq ft CFM = .33sf x 1414fpm CFM = 466 Note that this one register has over 1 ton of airflow. •197
    198. 198. We use Wrightsoft to calculate trunk reductions. It does so when velocity in the plenum reaches 50% of the original velocity. Note, old Manual D material said to reduce trunks every 24 ft. •198
    199. 199. We design your duct system to handle the total airflow at full capacity. When the unit is operating on 1st stage, the static is low, the watt draw is low, the velocity is low, and dehumidification and comfort are delivered. •199
    200. 200. We are able to show you how fresh air ventilation affects the load of your home. We can show you the difference between “straight” fresh air ventilation, Energy Recovery Ventilators (ERV’s), and no ventilation at all. See “Step 2 – Fresh Air Ventilation” on our website. Aprilaire 8126 Energy Recovery Ventilator •200
    201. 201. Never run your fan in the “on” position in an attempt to ventilate the home. Always run it in “auto”. • Leaks in the duct system create internal pressure problems inside of the home as well as Indoor Air Quality (IAQ) issues such as dust and odors. • Conduction gains or losses in ductwork installed in unconditioned areas leads to comfort issues. • Moisture that is removed from the air by the interior coil but has yet been drained to the outside is redistributed throughout the house. • It expends energy unnecessarily. •201
    202. 202. Make sure the p-trap is properly installed to prevent condensate from being pulled back in and redistributed throughout your home. •202
    203. 203. “Gook” build up in a condensate drain. Has anyone seen this before? •203
    204. 204. Make sure your condensate is properly drained away from the foundation. •204
    205. 205. Make sure you outside condensing unit is free of vegetation and blockage. •205
    206. 206. Make sure a high quality thermostat is installed on an interior, air sealed wall, away from heat sources and direct sunlight. Make sure the HVAC contractor properly explains how to properly operate the thermostat. •206
    207. 207. Lockout thermostats are required by the 2009 IRC to prevent electric heat-strips from operating until the temperature drops below the set- point. •207
    208. 208. Geothermal units along with the entire HVAC system qualify for a 30% rebate from the government until 2017. •208
    209. 209. We often witness homeowners spend large amounts of money on a geothermal unit(s) while… • Purchasing single speed units. • Attempting to save money using a single large 6 ton single unit instead of two separate units that are better suited for moving air properly throughout the entire home. • Under-sizing the ductwork. • Failing to install adequate returns/jumper ducts. • Failing to install fresh air ventilation. • Failing to commission the system especially when the ductwork is subcontracted out. •209
    210. 210. What is the correct solution for a single upstairs room or bonus room that is calling for only 1 ton? • Do you install a completely separate system? • Do you zone it? If so, do it right. • Do you install a ductless mini-split? •210
    211. 211. Ductless mini-splits are great for certain applications such as bonus rooms and light commercial applications. •211
    212. 212. My favorite ductless mini-split picture •212
    213. 213. Demand proper documentation and owner’s manuals for all of the HVAC equipment. • HVAC systems must be properly serviced and maintained. • Make sure proper the technician documents each and every visit. •213
    214. 214. Low priced HVAC systems are most often low quality HVAC systems. •214
    215. 215. • 13 SEER, single stage, permanent splits capacitor (PSC) units start at 1.5 tons and increase by half tons. • 14 SEER variable speed air handlers start at 2 tons and increase by 1/2 tons. There is no 4 ½ ton unit. • 2 Stage equipment starts at 2 tons and increase by whole numbers. • Ductless mini-splits come in a variety of sizes based on Btus. •215
    216. 216. An air-conditioner works by delivering liquid Freon through the refrigerant line to the cooling coil in the air-handler unit. The fan/blower is so important because it blows warmer “return” air from the home through the cooling coil where it is conditioned. The heat in the air causes the liquid Freon in the cooling coil to evaporate into vapor and hence the term evaporator coil. There must be a minimum amount of heat delivered to the cooling coil in order for the liquid Freon to turn to vapor. Reduced airflow reduces the amount of heat absorbed by the Freon and it will result in some Freon remaining in liquid form. In a perfectly operating system, all the Freon is in vapor form and it is transported to the compressor, where the gas is compressed back to liquid and the heat is pumped to the exterior of the home and hence the term heat pump. However, when liquid Freon is transported back to the compressor, the compressor attempts to compress the liquid and liquid cannot be compressed. On newer scroll type compressors, the liquid can usually be passed with minimal damage. But on reciprocating compressors, it can easily lead to compressor failure. If you have ever heard your HVAC unit “knocking” this is exactly what is happening. •216
    217. 217. Questions? todd@synergyairflow.com www.WeTestOthersGuess.com •217

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