This document discusses designing and building net zero energy homes in very cold climates. Key points include: - Aggressive energy conservation through a well-insulated building envelope is critical to achieving net zero, as it is nearly impossible without it. - Modeling the home's energy performance is important to optimize the design and minimize costs. This includes evaluating insulation levels, passive solar gain, and mechanical systems. - Windows are a major source of heat loss, so selecting high-performance windows is important for the design.

1. Net Zero Energy in Very Cold Climates

2. Habitat Studio has built
over 40 houses with
Energuide Ratings of 86 or
better
Our minimum energy
specification results in a
Energuide rating of 82

3. Net Zero Energy
• Produces all of its own energy
for Heating, DHW, Lighting
and Appliances on site over
the course of a year.
• Next to impossible without
aggressive conservation
!

4. • 54000 C Heating
Degree Days
• -340 C DesignTemp
Habitat Studio NetZero Energy Houses so far
Riverdale NetZero
Mill Creek NetZero
Belgravia NetZero Parkland NetZero
South Windsor Park
NetZero Holyrood Near
NetZero Retrofit
Edmonton
Winnipeg
• 59000 C Heating
Degree Days
• -350 C DesignTemp

5. Parkland NetZero
• LEED Platinum 4000 sqft two story with
finished basement, complex shape. 6
occupants
• 16,800 watts of PV, ground mounted with
2 way tracking
• 55% passive solar heated, 12% south
glazing with 2 1/2” concrete floor
• Electric boiler with in floor distribution.
• Good solar site for house and array
net-zero.ca/

6. Habitat Studio Net Zero houses this year
Allen Residence
Shute Salvalaggio Residence Kennepohl Franchuk Residence
Kosowan Ferrero Residence

7. • Panelized factory built
2x8 Filled with 5" 2lb
Spray foam & 2.25"
fibreglass
• East west facing site
• Air source heat pump
heating
• Air source heat pump
hot water
• 16.3 kW photovoltaic
system
• Landmark builds over
1000 homes per year
Landmark Group of Builders Ltd.

9. Net Zero in 10 easy steps
• Model the energy performance of your
preliminary design
• Use the modelling results to optimize
the building envelope and passive solar
gain
• Reduce base loads
• Domestic hot water
• Lighting and appliances
!
• Evaluate air source heat pumps or
geothermal and other renewables
• Size PV to meet remaining total load
Energy Reduction
Renewable Energy Collection
• Site assessment
• Preliminary design
• Optimize passive solar if available
• Finish detailed architectural and system
design

10. Using modelling to optimize the cost of
conservation measures
For Net Zero Energy at the Lowest Cost
Cost per kWh/year of energy
collection*=
Cost per kWh/year of energy
conservation
Cost per kilowatt-hour/year (kWh/a) of any
energy conservation measure
Cost of the measure divided by energy
saving in kilowatt-hours per year(kWh/a)
=
*Current cost of PV in Edmonton is $3.00
to $3.50 for the capacity to generate
1 kWh/year
N.B.This works until you run out of roof space and it ignores the fact that
there are primary energy consequences to exporting large amounts of energy
to the grid in summer and drawing it back in winter

11. • Conservation is the simplest, most economical and most
reliable route to energy and greenhouse gas reduction -
better than solar PV, solar hot water, better than
geothermal
• Without aggressive conservation there’s not much point in
planning for renewable energy collection
• The most benign energy available is the energy you don’t
ever need.
Building a Better Building Envelope
• Very hard to fix the
building envelope later

12. Preliminary Design
• Usual home design considerations- Job #1 is to
build a great place to live.
• Keep living spaces on the south side to make best
use of passive solar potential
• Try to accommodate space for PV generation
• Keep the shape simple and compact

13. Site
Assessment
• Evaluate the Solar Potential
• Consider potential shading from buildings, trees, etc.
• Potential for renewable energy collection
• Passive solar is not often available on urban lots, but when it is, it makes
net zero a lot easier.
S
January 15

14. Belgravia NetZero
• 1900 sq. ft. with basement suite (TFA 1981sqft /184 m2 ),
currently one occupant
• Excellent solar site
• 7740 watts of PV- 5160 watts moveable, 2580 watts fixed
• 12.6% south glazing area, 2 1/2” concrete on floors
• Dead simple, very low cost electric baseboard heaters and
DHW
• Incremental investment in conservation was partially paid for by
savings on the mechanical system
• Has used ~5600kWh/a for heating, lighting, appliances, and
DHW and generated 9600 kWh- a 4000 kWh surplus for two
years in a row. (30kWh/m2 all in).

15. 19°
53°
885 square feet
375 square feet
Roof shape and orientation
• When PV costs were $6.00 to $7.00 per installed peak watt we
angled the roof to get as much output as possible from each
module.
• Now with PV costing $3 to $3.50 per installed peak watt it makes
more sense to accommodate as many modules as possible and
accept lower output per module.

16. Modelling
• Good modelling is everything. Designing for net
zero at an optimum cost is almost impossible
without it. You're shooting in the dark
• Model early in the design process while it is still
easy to make changes and before people get
attached to particular configurations
• Model in house if possible, but if you can’t you can
still learn a lot by playing with the input values in a
model set up an expert evaluator.
• It seems like a lot of work, but can be done in a
couple of hours after you’ve done it a few times.

17. ModellingTools
• HOT2000 is tested, tried, and true. It is the basis for most
Canadian labelling and rebate programs
• Passive House Planning Package (PHPP) is excellent. It gives
very detailed feedback and lets you dial in the important details

18. Envelope Modelling/Optimization
• Determine Current PV cost or other benchmark energy price.
• Evaluate envelope upgrades with respect to cost per kWh/year of energy
saved.
• Optimize envelope specifications: foundation,walls, roof, windows, air tightness.
• Extra conservation cost can often be offset by simpler mechanical systems

19. Net Zero in 10 easy steps
• Model energy performance of
preliminary design
• Use the modelling results to optimize
the building envelope and passive solar
gain
• Reduce base loads
• Domestic hot water
• Lighting and appliances
!
• Examine / Model solar domestic hot
water and heating
• Consider Air Source Heat Pumps or
Geothermal
• Size PV to meet remaining total load
Energy Reduction
Renewable Energy Collection• Site assessment
• Preliminary design
• Finish detailed architectural and system
design

20. Options for walls with better performance than
2x6 16” O.C.
• 2x6 @ 24” O.C. (R 17.9 vs R16.5)
• 2x6 or 2x8 with high density foam -
• ICFs (Insulated Concrete Forms)
• SIPs (Structurally Insulated Panels
• 2x6 with 2x3 Strapping
• 2x8 24” O.C. with OVE details
• Double 2x4 walls - 10” to 16” thick
• Saskatchewan Double 2x4 wall
• 2x4 with Larsen trusses
• 2x6 with exterior rigid insulation foam or
rigid Roxul-
• REMOTE walls - see CCHRC site for
some great pamphlets

21. Considerations in choosing a wall system
• Lowest cost per effective R value
• Ease of getting ultra air tightness.
• Continuous insulation layer- no thermal thermal bridges
• Durability- vapour openness.
• Ease of construction
• not too disruptive of normal construction sequence
• minimal work from scaffolding

22. • As walls get thicker and tighter the sheathing
gets colder. Moisture that gets into the walls
from air leakage or diffusion will condense on
cold sheathing.
• OSB is almost a vapour barrier. It slows drying
significantly.
• Air leakage from inside the house can deposit
lots of water in the wall.
Better insulated walls have a higher moisture risk
Good sources of info
• Building Science Corporation http://www.buildingscience.com/documents/
bareports/ba-1316-moisture-management-for-high-r-value-walls/view
• CCHRC report on Moisture in REMOTE walls
• Air tightness of older-generation energy efficient houses in Saskatoon in
Journal of Building PhysicsVolume 36 Issue 3, January 2013 (email
pamerongen@habitat-studio.com for a .pdf)

23. High Density Spray Foam in a 2x6 wall
• R 24.8 (effective) for 2x6 24”
O.C
• Less fussy
• Less labour
• Use less space
• Good air tightness with some
remedial sealing
!
+
!
-
• Expensive
• No thermal break
• High embodied energy
• Less environmentally friendly- high
GHG emissions from blowing
agents
• Hard to renovate
• Not good for some small gaps
• Not as air tight as you would think

24. Riverdale Deep Wall
!
• Lowest incremental cost to get
R40+
• Follows normal construction
sequence
• Can be very air tight
• Versatile
• Almost the same amount of
dimension lumber as standard
2x6 @ 16” O.C.
• Minimal Waste
!
+
• Extra labour
• Fussy air sealing
• Takes extra space
• Hard to renovate
!
-

25. Passive buildings need to have
low thermal bridging.
• Both Construction Thermal
Bridges and Geometric Thermal
Bridges can be significant.
• At some point piling more
insulation onto the surfaces
doesn’t help much, and the joints
and points need to be looked at.
©Passive House Institute US 2013 – Certified Passive House Consultant Training
and points need to be looked at.
7
Picture Credit: David White

26. Thermal Bridging Control
• HOT2000 is responsive to thermal bridging control is a few
areas, but isn’t transparent.
• Effective R values depend on continuous insulation layers.
• Passive House Planning Package (PHPP) requires detailed
input and gives good feedback on the consequences of
thermal bridging.
• Eliminating thermal bridging will reduce heat loss
substantially whether you can calculate it or not.

27. • Air tightness is by far the cheapest energy
reduction investment you can make
• Air test results of 0.6ACH 50 or better are
achievable in wood frame buildings.
• Keeping uncontrolled air leakage out wall
assemblies enhances durability
• New vapour open air sealing products and
techniques are one of the biggest benefits of the
Passive House approach.

28. Windows
Courtesy of the US DOE
Windows and doors are the single biggest source of transmission
heat loss - often 40% or more of the total building heat loss.

29. Window Shopping- features to look for
• Low conductivity (Low U value/high R
value) glass
• High solar heat gain coefficient (on the
south)
• Low conductivity (Low U value/high R
value) frames
• Slim profile frames- typically the glass will
have a better U value than the frame
• Low conductivity spacer bars
• Good airtightness- preferably triple weather
stripping
• Durable
• A few large windows (less frame and
framing) will use less energy and cost less
than more small windows of the same total
area.

30. Heat RecoveryVentilators
• Any air tight building requires a
continuous supply of fresh air.
Heating ventilation air can require up
to 20% of the total heating energy
• HRV’s are an essential component of
high performance housing
• Most HRV’s have relatively low
efficiency. ( ~55 to 65%)
• High efficiency HRV’s (80 to 95%)
are a good investment and have a
short payback.

31. Total Annual Heating Energy Reduction(kWh/year)
Domestic Water Heating
Cooling
Lighting and Appliances
*Net Annual space Heating
*Including passive solar and internal gains and heat pump C.O.P.

32. • Low flow shower heads
• Efficient Hot WaterTanks
• Water conserving dishwasher
• Water conserving clothes washer
• Grey water heat recovery
Domestic Hot-Water Energy
Reduction

33. • Energy Efficient Appliances
• refrigerator
• clothes washer
• No Dryer
• Range/ Pressure cooker
• Energy Efficient Lighting
• compact fluorescents
• LEDs
• task lighting
• day lighting
• Energy Efficient Motors
• ventilation
• heating
• Phantom Load Control
• The Energy Detective(TED)
monitor
Electrical Load Reduction

34. Riverdale NZ Heating Schematic
SolarThermal Space Heating
7- Zen 28S Collectors
• Can be very expensive if you size it to meet a high
percentage of the winter load.
• Not enough energy available when you need it most
• Can be very complicated
• Potential to harvest more useful energy per sq. ft than
PV (~20 kWh/sq.ft./year)
• Incremental cost at Riverdale~ $50000 per unit
Fresh Air
from
Outdoors
Exhaust
Air to
Outdoors
Exhaust Air from
Bathrooms &
Kitchen
Return Air
from
House
Fan Coil
Heated / Cooled
Air to House
7 Solar
Heating
Collectors
Domestic
Hot Water
Domestic
Cold Water
from Mains
Drain
Water Heat
Recovery
Electric
Heating
Element
Fan Coil
Pump
2 T
Heat
Pump
Ground Loops
GL1. 41 m under garage
GL2. 55 m around foundation
Daily Heat Storage Tank
Seasonal Heat Storage Tank
Tempering Valve
17,000 litres
water
300 litres
water
Cold Water
to Interior
Uses
Heat
Recovery
Ventilator
Fan
Fan
Dwg M1. Riverdale NetZero House Mechanical Systems Layout
ver 3d Drawn and developed by: David Morrow, Hydraft Development Services
Peter Amerongen, Habitat Studio and Workshop
Monitoring Instrumentation: Gordon Howell, Howell-Mayhew Engineering
Date: 2008 August 02
55°C to
80°C
5°C to 90°C
6 GJ of heat
Fresh Air
to House
Fan
Daily Storage
Tank Bypass
Valves
Fan Coil
Bypass
Valves
Seasonal
Storage Tank
Bypass
Valves
Drainback
Tank
30 litres
water
Surface
area:
21 m2
Cold Water
to Exterior
Uses
WM-cmWM-dh
Tsolar-in Tsolar-out
Tfc-in
Tfc-out
T1
T3
T4
T5
T8
House
Temperature
Outdoor
Temperature
T6
a
b V1
HX3
HX2
HX1
E1
V3
a
V4 a
b
V5
b
a
V7
a
b
V6 a
b
P2
F1
F2
F3
Fsolar
Ffc
HX4
Tempered
Water to
Showers
WM-cx
Solar
Collector
Pump
P1
Solar Supply
Heat Meter
HM-ss
a V2
b
Vent
T2
c
V8
a
b
c
GL1
Daily
Storage
Tank
Bypass
Valves
Seasonal
Storage
Tank
Bypass
Valves
GL2
Heat Pump
Pump
Fan Coil
Heat Meter
HM-fc
b
Heat from solar collectors
Solar heat to daily tank
Solar heat to seasonal tank
Potable water
Stored heat from seasonal tank
Stored heat to fan coil
Stored heat to daily tank
Stored heat to heat pump
Concentrated heat from heat pump
Heat to/from ground loops
Cold Water
Pre-Heat
HX5
T7
Colour Legend
for Heating Loops:
P3
Nearest Nuclear
Fusion Furnace
Notes:
1. Ground loops intended to provide space cooling only.
2. Heat pump supplements the moving of heat if
required:
a) from seasonal tank to fan coil by taking the
seasonal tank from 25°C down to 5°C;
b) from seasonal tank to daily tank; and
c) from fan coil to ground loops for space cooling.
3. Manual valve sets V7 and V8
a) “a” is mainly used to create backpressure so loop
remains pressured while serving the
non-pressurised tank;
b) “a” & “b” are used for seasonal selection of ground
loops for cooling;
c) “c” is for isolation only – it is normally open.

35. Net Zero in 10 easy steps
• Model the energy performance of your
preliminary design
• Use the modelling results to optimize
the building envelope and passive solar
gain
• Reduce base loads
• Domestic hot water
• Lighting and appliances
!
• Consider Air Source Heat Pumps or
Geothermal
• Size PV to meet remaining total load
Energy Reduction
Renewable Energy Collection
• Site assessment
• Preliminary design
• Optimize passive solar if available
• Finish detailed architectural and system
design

36. • The energy harvested by Air
Source Heat Pumps is 100%
renewable - solar energy with no
direct sun.
• It is possible to get C.O.P.’s* of 2 or
better in Edmonton or Winnipeg.
• C.O.P. drops off as temperature get
colder.
• Mitsubishi ‘Hyperheat’ units have
shown C.O.P.’s of greater than 1.0
at temperatures as low as -30℃
• They can make or break the
attempt to get to net zero energy.
0"
5"
10"
15"
20"
25"
30"
35"
40"
45"
50"
1"
13"
25"
37"
49"
61"
73"
85"
97"
109"
121"
133"
145"
157"
169"
181"
193"
205"
217"
229"
241"
253"
265"
277"
289"
301"
313"
325"
337"
349"
361"
Series1"
Edmonton Heating Degree Days 2013
Mitsubishi ‘Hyperheat’ cutoff (~-25℃)
*C.O.P. - Coefficient of Performance
C.O.P. of 2 indicates 2 units of energy out for
every 1 unit of electricity in.
Air Source Heat Pump Operating Range

37. Heating and ventilating with a small mini split air source heat pump
*Needs EGH 86 or
better envelope
Mini split outdoor unit
Fresh air from
outside
Fresh air to house
Exhaust stale air out
Mini split indoor
unit c/w blower
Stale air exhaust
from kitchen,
bathrooms
and laundry
Transition
supply duct
Controller to sync mini split fan
with thermostat and post heater
10kW Thermolec
Post Heater
HRV
12" round duct to
supply heating and
fresh air to house.
500CFM at
< 0.36 in.WG
12 " return air from house

38. Mini splits vs Central systems
• Ductless mini splits can save heating
system dollars if the loads are small
enough to be met with point source
heating and electric baseboard back up.
• Big central ASHP’s like the Mitsubishi
Zuba Central will add ~$8000 to
heating system costs.
• Even at that price central systems can
pay for themselves in offset PV costs.
For example, if it saves 3000kWh/year
if will offset $10,500 worth of PV and
also need less roof space.

39. Air Source Heat Pumps for Domestic Hot Water
• Relatively low cost $1500-2000
• Provide a small summer cooling
benefit
• Work well in tandem with Air
Source Heat Pump or
Geothermal heating.
• Will shrink the size of the PV
array
• Annual COP of ~1.50 to1.75 is
possible
• Provides a small amount of
summer cooling
!
+
!
- • Will increase winter heating load
• Noisy

40. Photovoltaic Electricity (PV)
!
• Requires lots of roof space- 100 sq.
ft. to generate 1500 kWh/ year -
more if you have shading
• Expensive ~ $3.00 to $3.50 per
installed watt of peak capacity.Typical
NZ system $30,000 to $40,000(Each
installed watt in Edmonton will
produce 1.1 kWh per year.)
• Supply is out of sync with demand -
grid dependant.
!
• Very simple installation, durable, almost no
maintenance
• Can be added later if roof space is available
• With grid tie it doesn’t matter that supply and
demand are out of sync.
• “PV is a rock the makes electricity” Martin
Holladay
!
+
!
-

41. Mosaic Centre Case Study
• New 30,000 square foot office building in south Edmonton
• Beautiful, healthy, nurturing, affordable place to work for
the Mosaic Group of Companies.
• Headquarters for Oil Country Engineering Services Ltd
• Includes a daycare, co-working spaces, a wellness centre,
and an incubator for other greener businesses
• Natural daylight in all work spaces.
• Project environmental goals
• Net zero energy
• LEED Platinum Certification
• Living Building Challenge

42. Process
• Energy modeller was hired before the architect
• Achieving the project goals using conventional fixed price
contracting was going to be unaffordable
• Early commitment to Integrated Project Delivery
• Careful team building prior to design.
• Open documentation of project successes and failures. http://
themosaiccentre.ca/

43. Mosaic Centre IPD
• Early involvement of key participants
• Shared risk and reward based on project
outcome
• Joint project control
• Reduced liability exposure
• Jointly developed and validated targets
Bullitt Center

44. Mosaic Centre: In pursuit of Net Zero*
* For the whole report: http://themosaiccentre.ca/wp-content/
uploads/2014/09/2013-06-13-ReNu-C3-Report-3.pdf

45. Mosaic Centre: In pursuit of Net Zero

46. • More efficient servers and monitors
• Shaved lighting loads
• Reduced cooling load
• Utilizing waste heat from servers for
heating
• Geothermal heating and cooling
• Higher efficiency PV
The IES run on versionC3 IES shows consumption for that
design to be ~185,000 kWk/a. So they kept hunting.
Solutions include:

47. • Project is under budget and 4 months ahead of schedule. Due to be
complete in February 2015.
• There have been mistakes, a few of which would normally have been
very costly and time consuming. The IPD team pulled together and
corrected them quickly at a fraction of the expected cost.
• Premier quality, net zero energy building, being built at a premium of 5
to 10% over the cost of standard market space.
Results
• Savings from reduced
lighting, heating and cooling
loads did result in some
reductions in equipment
cost that have helped to
pay for the envelope
upgrades

48. Passive House
• Started about 20 years ago when some Bo Adamson a German engineer
and Wolfgang Feist a physicist set out to reduce heating and cooling
energy to a level (about a 90% reduction) that would be sustainable and
leave room for the developing world to catchup.
• Building on the 1970’s work of Harold Orr (The Saskatchewan
Conservation House) and William Shurcliff in the US, with stereotypical
German thoroughness they built a heating and cooling demand spread
sheet that accounted for everything.
• There are now ~30,000 Passive House buildings worldwide, several
thousand in the US and a few dozen in Canada.

49. • Annual heating and cooling energy demand limited to 15 kWh/m²
• 0.6 Air Changes per hour
• 120 kWh/m² primary energy demand.
Passive House Metrics
Buildings designed and built to the passive house standard are among the most energy
efficient, the healthiest, the most comfortable and durable buildings ever built.
The drive to meet this standard has powered innovation in building
science, building techniques and building components. These innovations
include:
• Very high efficiency HRVs
• Very high performance windows and
doors
• Highly effective air sealing products
and techniques
• Vapour open sheathing materials
• Highly insulated , thermal bridge free,
vapour-open assemblies
• Hygrothermal analysis software
• Fine grained, detailed energy analysis
tools (PHPP) now with a Sketchup
interface

50. • House area is ~ 1600 sq. ft with a
finished basement(TFA=246m2)
• 15kWh/m2 if .35 ACH50
• Thanks to Jim Zeibin and David
Zeibin Architect
Cottonwood Passive House

51. U value
w/m
R value
Concrete Foundation wall 0.113 50
Double stud exterior wall 0.076 75
Truss roof 0.058 98
Floor slab 0.119 48
Windows Internorm
Air tightness target 0.3ACH50
HRV
UltimateAir DX 300
Cottonwood Specifications

53. • Hard to meet the target with single family housing here in the frozen
north, but your building will be better for the attempt.
• Multifamily is doable.
• PHIUS is about to roll out a climate specific standard, that will be more
achievable here.
• Training: great courses available from CanPHI West and PHIUS

54. www. habitat-studio.com