Amber Wood presented on improving the energy efficiency of aging residential housing through a pilot program. She discussed the Greenbelt Homes community which consisted of 1,600 units built in the 1930s-40s that underwent an energy upgrade in the 1970s. The pilot program targeted 7 buildings with 28 units for baseline monitoring and envelope and HVAC upgrades. Wood summarized the pre-remodel assessment and provided recommendations for upgrades to different housing construction types. She outlined plans for long-term energy and performance monitoring to evaluate the impacts of the retrofits.
1. Changing with the Times:
Major Improvements to the
Energy Efficiency of an Aging
Residential Community
Amber Wood
Manager, Energy Programs
International Builders’ Show
February 11, 2012
Driving Innovation in Housing Technology
2. Building America
Private/public R&D
partnership sponsored by
DOE
Energy-efficient solutions
for new and existing
housing
Technologies/Systems
Whole-House Test Homes
Quality Processes
3. Presentation Topics
Greenbelt Homes (GHI) pilot
project
GHI Crawlspace Scope of Work
(SOW)
Needs & motivations for adding
energy efficiency to remodeling
3
4. Greenbelt Homes, Inc.
Privately-owned
co-op
1,600 units
4 units/building
Courtesy of www.greenbelt.com
1930’s-40’s
Roosevelt work-
force housing
15. Construction Total No. of
General Conditions
Type Units
Frame Built in 1941-42, unit sizes range from 574 to 928 sq ft. and 992
Vinyl-Sided consist of the following features: (140 of
• Common ventilated crawl space of 8” CMU block, 4 ½ these are
courses high (3’) apartments)
• 2x8-16”o.c. floor joists with mid-span dropped beam 3-
2x10” on CMU piers
• R-11 kraft-faced fiberglass batt insulation in floor joists
(1980)
• Balloon-framed 2x4-16”o.c walls
• Blown-in cellulose insulation in walls (1980)
• Board wall and roof sheathing (1x6/1x8)
• Double glazed vinyl or aluminum windows (1980)
• Vinyl siding, no WRB
• Gable roof with asphalt shingles
• Ventilated attic
• Attics are insulated with rock wool, blown-in cellulose, and
fiberglass batt floor insulation (1980 to present)
15
16. Construction Total No.
General Conditions
Type of Units
Frame Built in 1935-38, unit sizes range from 555 to 1,577 sq ft. and 318
Brick-Veneer consist of the following features:
• Formed concrete crawl space foundations, with structural
concrete first floors over common crawl spaces
• Crawl spaces are 4’ and retrofitted as closed crawlspaces
with 1” to 2” of rigid extruded polystyrene foam applied to
the perimeter walls
• Crawl space walls extend under front and rear porch slabs
(many exposed to ambient conditions)
• Structural concrete first floor
• Main house and porch slabs lack thermal breaks
• Balloon- framed 2x4-16”o.c. walls with plasterboard interior
finish
• Blown-in cellulose/rock wool insulation in walls (1980)
• Board wall and roof sheathing (1x6/1x8)
• Exterior brick veneer, no WRB
• Double glazed vinyl windows (1980)
• Gable roofs with slate shingles
• Ventilated attic with rock wool, blown-in cellulose, and
fiberglass batt floor insulation (1980 to current)
16
17. Construction Total No.
General Conditions
Type of Units
Block - Built in 1935-38, unit sizes range from 555 to 1,577 sq ft. and 256
8” CMU consist of the following features:
• Formed concrete crawl space foundations, with structural
concrete first floors over common crawl spaces
• Crawl spaces are 4’ and retrofitted as closed crawlspaces
with 1” to 2” of rigid extruded polystyrene foam applied to
the perimeter walls
• Crawl space walls extend under front and rear porch slabs
(many exposed to ambient conditions)
• Structural concrete floors (1st and 2nd levels)
• Main house and porch slabs lack thermal breaks
• CMU walls, finished with plaster
• Some interior common walls are wood-framed (where
party walls breach the adjacent units’ footprint).
• Double glazed vinyl windows (1980)
• Exterior walls are painted (B) or have vinyl siding attached
(BV)
• Flat concrete roofs retrofitted with 3 ½” of polyisocianurate
insulating tapered sheathing and EPDM roofing
17
18. Baseline Short-term
Testing
Blower door test
Courtesy of www. energyconservatory.com
Multi-point house
depressurization
Multiple blower doors
Simultaneous testing in
adjacent units
18
19. Baseline Short-term
Testing
Significant air leakage
Attic access panels
Air conditioners
Penetrations (doors, mail slots,
windows, electrical, plumbing)
19
21. Simulation Parameters
13 of the 28 homes Frame w/Brick
Painted block End & inside units
End & inside units Frame w/Vinyl
Block w/ Vinyl End & inside units
End & inside units End, front addition
End & inside units w/ End, side addition w/ large
basement glass area
End, full rear addition
Inside, full rear addition
21
Artwork by Isabelle Gournay courtesy of www.greenbelthomes.net
22. Beopt Energy Simulation
Optimizations
All electric
Source savings = electricity savings
Annualized cost of the upgrades + utility costs
30 years at 7%
Block unit example:
22
23. Energy Simulation
Optimization
Block unit example
Costs & savings comparison
23
24. Installation Costs for Building
Envelope Improvements
Evaluated on a per-building
basis
Do not include remediation
associated with environmental
hazards (such as lead paint,
radon, or asbestos)
Costs are exclusive of
management fees
24
32. Energy & Performance
Monitoring
Indoor air temperature and relative
humidity in multiple locations;
Crawlspace and outdoor temperature and
relative humidity;
Heating energy use (where feasible);
Hot water energy use;
Dryer energy use (if applicable); and
Total electric energy use.
32
Photo courtesy of www.greenbelthomes.net
33. Parameter of Test Method Purpose
Interest
Whole House Energy transducer and Record whole house electricity use
Electric Energy recording devices Develop use profile for winter months
Use Integrate energy use data with general weather
data
Provide comparison with energy simulation results
Space and Water Energy transducers and Proportion heating energy use as a fraction of total
Heating and recording devices energy use
Dryer Energy Summarize total internal heating energy and
Use major loads
Indoor Temperature/Relative Provide indoor conditions for energy analysis
Environment Humidity sensors – 3 to 4 Assess interior moisture loading/dilution
devices per unit, located 1st Support ventilation option development and control
and 2nd floors Assess range of indoor temperature settings
Foundation Temperature/humidity Provide crawl space foundation conditions for
Environment loggers, at least 2 sensors in energy analysis
crawl space Assess potential moisture issues
Compare with air sealing/ventilation/insulation
options in pilot renovation plan
33
37. Retrofit Solutions for
Enhancing Energy Efficiency
Energy Savings: Household to National
Comfort: Temperature swings to
consistency
Moisture: Reduce potential problems
Indoor Air: Controlled ventilation
Technology: Options and performance
Installation: Contractor training/QA
Cost: Installation/operation/savings
Value: Demonstrate values at sale
44. Crawlspace Scope of
Work (SOW)
Vented or Unvented
Correct existing issues
Address moisture
Air sealing
Insulation
44
45. Detailed SOW
A. Correct exterior moisture and thermal conditions
B. Remove wet products and debris from the interior
C. Repair structural damage
D. Repair/install interior foundation drain system
E. Correct interior floor moisture conditions
F. Correct interior wall moisture
G. Remove mold and replace rotten wood
H. Repair/install ground vapor barrier
I. Correct structural defects – i.e. load path tie-down hardware
J. Repair/replace HVAC, pipes, ducts, and equipment within crawlspace
K. Seal interior thermal boundaries
L. Insulate floor system and air seal assembly (ventilated crawlspace)
M. Insulate crawlspace wall (closed crawlspace)
45
53. Needs & Motivations of
Remodelers
Current remodeling industry
Role of energy efficiency
Identify the gaps and barriers
Quantify and prioritize needs to
increase sales & projects involving
improving home energy efficiency
53
54. Remodelers’ View of Current
Industry & Energy Efficiency
(initial set of focus groups)
54
55. Current Remodeling Industry
The economic climate has shifted greater
to focus to remodeling
More consumers are staying in their homes
Many builders are turning to remodeling work
Competitive, price sensitive market due to
Lending restrictions
Lack of appraisal value on energy efficient
upgrades
Flood of individuals into the remodeling arena
55
56. Current Industry (cont.)
Qualified remodelers strive to
differentiate themselves
Convey to the consumer the value of an
experienced, qualified remodeler
Position the remodeler as the expert &
serve to build trust and confidence
among consumers
56
57. “This is the way we build”
Believe energy efficient upgrades are part of “doing things the right way”;
incorporate as part of their business model
Have certain upgrades that include as standard part of process, if warranted
Approach as “this is what we’re going to do” then educate consumer as to
why they do it
“My responsibility to recommend”
Believe energy efficient upgrades are in customer’s best interest and actively
seek opportunities to recommend upgrades
Seek to guide consumers as to benefits; try to drive them toward it
May recommend upfront, but most often wait until have gotten a feel for the
house and customer
“We’ll offer as an option”
Intellectually know it should be recommended, but don’t have strength of
conviction
View more as a consumer driven decision; give them information then let them
decide
Anticipate consumer bottom line focus
57
58. Role of Energy Efficiency
in Remodeling
Provide a cost/benefit analysis for
energy efficient upgrades
Include an energy audit assessing
energy consumption & lifestyle
Demonstrate potential savings for
various upgrades; connect the dots in
terms of upgrades and real world
benefits.
58
59. Best Approach to Energy
Efficiency
Knowledgeable
recommendation with the
consumer’s best interest in
mind
Sales attempt with the
remodeler’s/builder’s
financial interest in mind.
59
60. Remodelers’ Gaps & Barriers to
Adding Energy Efficiency into
Remodeling
(2nd set of focus
groups)
60
61. Gaps & Barriers to Adding
Energy Efficiency
See growth potential for energy
efficient upgrades
Long-term success is dependent on
upgrades becoming market driven.
Need incentives based on improved home
performance (not specific products)
Shifting homeowner mindsets to
“performance” of the home
61
62. Challenges . . .
Perceived value in doing energy
efficient upgrades
Costs
Auditing/testing
Limited homeowner resources
Energy savings vs. upgrade investment
Energy efficient improvements do not
add appraisal value
62
63. Reasons to Invest in Energy
Upgrades
Motivators Include:
Reducing monthly energy bills
Having more predictable energy bills
Increased comfort
Improving indoor air quality
Environment, conservation, and/or green
Helping homeowners to connect the dots
between a problem and solutions is
necessary for buy in
63
64. Selling vs. Solutions for
Remodelers
Educational information regarding
energy inefficiency can create
awareness
Did you know that you could be paying
more than you should be in monthly
energy costs because of leaky ducts,
drafts, outdated heating & cooling systems
or insufficient insulation?
64
65. Growing Energy Upgrades
Nationwide existing home
performance scores
Establishing appraisal value for
energy efficient upgrades
Realtor education as to value energy
efficient upgrades bring, and how to
sell the features
Points off mortgage interest for
energy efficient upgrades
65
66. Tools Needed
Informational/educational resources
Shift consumer thinking to home
performance
Increase understanding of problems
Understand benefits of various types of
upgrades
Website, DVD, printed materials
66
67. Tools Needed (cont.)
Consumer campaign
Free/low cost energy audits for
homeowners
Key questions to ask in order to
identify opportunities
Means of quantifying impact of
energy efficient upgrades
Connecting remodelers with energy
auditors to develop referral network
67
69. Prioritize the Support
Needs
Quantitative market research
with remodelers.
Build upon the qualitative
remodeler focus groups,
Quantify and prioritize the
support needs
Increase sales and projects
involving improving home energy
efficiency 69
70. What percentage of your recent clients
fit into the following groups when it
comes to accepting energy efficient
upgrades?
% Clients in Following Groups Mean
Bottom line focused - will not spend any more 40%
than they have to.
Can be convinced - may or may not think about 39%
energy efficiency, but are open to the upgrades
once they understand the benefits.
Embraces, or actively seeks, energy efficiency. 21%
Total 100%
70
71. When working with clients, which of
the following statements most closely
describes your company’s approach to
energy efficient upgrades?
Company Approach to Energy Efficient Upgrades Freq.
We do not try to sell or offer energy efficient 6%
upgrades unless they are specifically asked for by
the client.
We offer or recommend it when the energy 51%
efficient upgrade is cost effective and is directly
related to the home improvement project.
We believe energy efficient upgrades are part of 43%
“doing it the right way” and incorporate this into
as many remodeling jobs as possible.
Total 100%
71
72. What is the relative importance of all of
the issues?
Priority Issues sorted by Importance to Remodelers
1 Appraisal values factor into what type of remodels clients are
willing to undertake, and energy efficiency is difficult to value.
2 Clients are typically unable to discern between high quality and low
quality construction at the bidding phase. Often they select the
lowest cost bidder. This makes selling upgraded energy efficiency
difficult.
3 Realtors, who are in contact with homeowners as they buy/sell
homes, aren’t able to describe the value of energy efficiency.
4 There is no standard way to compare a home’s energy efficiency
when buying or selling an existing home.
5 Homeowners want to see tangible differences, often focusing on
aesthetics or functionality, which makes energy efficiency a difficult
sell.
72
73. What is the relative importance of all of
the issues?
Priority Issues sorted by Importance to Remodelers
6 One popular way to determine airtighness, a blower door test, is
expensive and most clients are not willing to pay for just an
evaluation.
7 Homeowners see energy efficiency upgrade costs as an expense
and not an investment.
8 Clients don’t understand the value of energy efficiency. They place
little value on it. If consumers don’t see a problem, then they won’t
purchase the solution.
9 There is little real demand for energy efficiency. Homeowners are
just following the money for rebates.
10 No coordinated efforts between the federal government, state
government, and utilities when it comes to offering, applying for,
and complying with energy efficiency incentive programs.
73
75. Resources
Building America
www.eere.energy.gov/buildings/building_america
Builders Challenge
Program: www.eere.energy.gov/buildings/challenge
NAHB Research Center
Main Website: www.nahbrc.com
Technical Info: www.toolbase.org
77. Thank You!
Amber Wood
NAHB Research Center
Manager, Energy Programs
400 Prince George’s Blvd Upper Marlboro, MD 20774
(direct) 301.430.6309 (fax) 301.430.6180
www.nahbrc.com
Driving Innovation in Housing Technology
Editor's Notes
Oil fired boilers replaced for safety reasons – changed to baseboard heatingIndividually controlled baseboard electric heaters were installed in each room, except in kitchens and bathrooms where ceiling fan-coil heaters with wall-thermostats were installed; Upgraded electrical and installed individual meters for each unitFifty-two (52) gallon electric water heaters were installed for use in every home;Insulation was added in attics, crawl spaces and exterior walls of vinyl-sided frame homes; in attics and crawl spaces of brick homes and in crawl spaces of block homes.Original steel-frame casement windows were replaced with vinyl or aluminum double-glazed window units.
BackgroundGoals: Health & safety Comfort Increased IEQ Durability Affordability Lower utility bills Maintenance
Collaboration of GHI, NAHBRC, & NREL
Collaboration of GHI, NAHBRC, & NREL
Recording house and window dimensions (including additions),Determining insulation levels in the walls, ceilings, and foundations,Documenting equipment and appliance models,Noting locations of baseboard heaters,Calculating capacity of heating and cooling equipmentDetermining the hot water system configuration
The Research Center performed short-term testing in conjunction with the walk-through evaluations. This testing included performing a blower door test for each unit (hot water temperatures and fixture flow rates were also measured). Multi-point house depressurization measurements provided total air leakage (which would include leakage to adjacent units) and leakage to the outdoors. Leakage to outdoors was determined by simultaneously running blower doors in adjacent units. Significant air leakage was consistently noticed at the attic access panels, around through-wall and through-window air conditioners, doors, mail slots, and windows, particularly the windows that were unlatched due to malfunction. Frame houses all had significant leakage through the floor at electrical and plumbing penetrations, particularly at the water heater closet. A duct blaster test was performed on the one unit with a ducted system. The air flow of the bath exhaust fans was measured using a flow hood. The actual air leakage measurements were used in simulation models for specific units.
The Research Center performed short-term testing in conjunction with the walk-through evaluations. This testing included performing a blower door test for each unit (hot water temperatures and fixture flow rates were also measured). Multi-point house depressurization measurements provided total air leakage (which would include leakage to adjacent units) and leakage to the outdoors. Leakage to outdoors was determined by simultaneously running blower doors in adjacent units. Significant air leakage was consistently noticed at the attic access panels, around through-wall and through-window air conditioners, doors, mail slots, and windows, particularly the windows that were unlatched due to malfunction. Frame houses all had significant leakage through the floor at electrical and plumbing penetrations, particularly at the water heater closet. A duct blaster test was performed on the one unit with a ducted system. The air flow of the bath exhaust fans was measured using a flow hood. The actual air leakage measurements were used in simulation models for specific units.
Plus visual inspection & utility bills
Energy Simulation Optimization
Energy Simulation Optimization
Features that are not directly responsible for increased energy efficiency were added to the estimated cost analysis to enhance building durability and/or indoor air quality. These are: Mechanical ventilation and controls to provide point source and whole house air exchange; andRemediate crawlspaces to improve insulation performance and indoor air quality through minimizing moisture entrance to the home through the crawlspace
While it is admittedly tidy and perhaps overly-simplistic, the majority of the building envelope improvements recommended have been assigned useful life spans of 30 years. The life span coincides with the estimated life of the assumed mortgage (if used to purchase the upgrades). GHI reserve estimates have placed various life spans from 35 to 40 years (vinyl siding on smaller frame homes and windows) to 85 years (exterior doors) on these building elements. Because they are each integral components of the building system, replacement should be planned to occur at the same time to protect the integrity of the buildings. For internal reporting and reserve calculations, the useful lives can be adapted to reflect the experience of GHI and warranty periods offered by the manufacturers whose products are selected for the pilot study.
Exterior Wall Insulation2” thickness (extruded polystyrene, XPS, or polyisocyanurate) or 3” expanded polystyrene or polyisocyanurate materialThe masonry block and masonry brick frame crawlspace foundations extend continuously around the buildings encompassing the front and rear porch slabs, as well as the conditioned spaces. Where these do not have an addition (conditioned space) above, two inches of closed cell SPF, R-12, should be applied to the bottom of the slab, accessible from the crawlspace. Unconditioned porch slabs average roughly 400 square feet per building.
Attic insulation currently is about R-16
For this building type, it is recommended that the existing siding be removed and a weather resistant barrier (WRB) is installed over the wood sheathing and sealed. One inch thickness of rigid foam, R-5 to R-7, installed beneath the horizontal vinyl siding that is scheduled for replacement between 2015 and 2023, is also recommended to compensate for the blown-in cavity insulation which may have settled in the wall. The WRB or the foam should be installed and taped to provide an air barrier over the exterior sheathing which consists of 1”x6”/1”x8” boards.
Integrating needs & values
Homeowner mindset - better conditions them to understand the value of making energy efficient upgrades beyond the scope of their remodeling project.