1. Affordable Housing Focus on
Efficiency
Remodeling & Passive House Approaches
Greenprints Conference March 14, 2011
Amber Wood, Manager Energy Programs
NAHB Research Center

2. The NAHB Research Center’s mission . . .
promote innovation in housing technology to
improve the quality, durability, affordability, and
environmental performance of homes and home
building products.
2

3. Department of Energy
Programs
 Building America
 DOE’s residential research &
development (R&D) program
 Builders Challenge
 DOE’s energy efficiency
certification for homes

4. 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

5. High Performing Home Goals
 “High Performing Homes”
that are
 Energy efficient
 Durable
 Comfortable
 Healthy to live in
 Safe
 Affordable
In other words . . . Green.

6. Existing Homes Opportunities
 20% of pre-1980 homes
are well insulated
 Air Sealing . . . & insulation
 More uniform temperature
 Increases comfort
 Costs
 Energy costs increasing
 Increased retrofit costs are
often offset by increased
Source: 2007 Buildings Energy Data
Book, Table 4.2.1., 2005 energy cost data savings
 Tax credits and rebates

7. Building America Integration
 Whole-House Design
 Design/Implement energy
efficient solutions
 Work through implementation
issues
 Technical product/system designs
 Details
 Process (quality management)
 Simulations/Analysis
 Cost optimization

8. Whole-House Re-Design
Renewables
Systems Solar Electric (PV)
Wind
Heating
Cooling
Building Right-Sized
Envelope Ducts
Ventilation
Durability Dehumidification
Moisture
Safety Bulk Hot Water
($-$$$$$) Vapor Piping COST
Structural Drainage
Combustion Air Sealing Appliances
START Lead Insulation Lighting
Asbestos MELs
HERE Mold
Moisture
ENERGY EFFICIENCY
8
SAVINGS POTENTIAL

9. Montgomery County
Habitat for Humanity

10. New Horizons for Remodeling
 Constraints & Design Opportunities
 Durability
 Energy Efficiency
 “Test-in” Data
 Identify products/methods
 Details
 Documentation
 “Test-out” Data
 Energy Savings Simulations
 Technical/professional development

11. List of EE Recommendations
 Moisture: Exterior grading & sump pump operation
 Air Sealing
 Insulation
 Ventilation
 Windows
 System Evaluations
 HVAC
 Ducts
 Water Heating
 Equipment Specifications
 Direct vent, minimum 92% AFUE gas furnaces
 14.5 SEER cooling
 size in accordance with ACCA Manual J/S
 Programmable thermostats

12. List of EE Recommendations
 Ducts
 Seal all ducts
 Relocate supply and return ducts to floor
 Return air paths for all rooms
 Duct exhaust fans to the outdoors
 Kitchen
 Bath
 MERV 8 minimum filtration
 Hot Water & Water Distribution
 Direct vent/power vent water heaters
 Insulated hot water piping
 Low flow faucets, shower heads, and water closets
 ENERGY STAR appliances
 ENERGY STAR lighting
 Construction Sequence

13. Clear Improvement: Wall Insulation
R 4.7 original to R 20 retrofit

14. Calculated Improvement
Wall U-value calculation Original Block Wall Original Remodeled Block Wall
Cavity Framing Isothermal Cavity Framing Isothermal
still air Interior film 0.68 0.68 0.68 0.68 0.68 0.68
sheetrock Interior covering 0.45 0.45 0.45 0.45 0.45 0.45
2x4 wall Framing/cavity R 13 4.2 8.772
1" foam Interior insulation 5 5 5
fir strips & air Framing/cavity R 1 0.9 0.975
4" block Block Wall 1.93 1.93 1.93 1.93 1.93 1.93
air gap Exterior air gap 1 1 1 1 1 1
brick façade Exterior covering 0.48 0.48 0.48 0.48 0.48 0.48
outside air Exterior film, winter 0.17 0.17 0.17 0.17 0.17 0.17
Isothermal Plane 4.7 R-value 19.5 R-value
Parallel Path 4.7 R-value 20.8 R-value
2
* R-values in hr∙ft ∙°F/Btu

15. Other Wall Improvement
Opportunities
 Frame wall option 1:
 Add 1” exterior insulation
when siding is replaced
 R 11.8 to R 17.4
 Frame Wall Option 2:
 Build 2x4 wall inside of
2x4 wall (both R 13)
 R 11.6 to R 20.2

16. Calculated Improvement
Wall U-value calculation Hathaway Addition Framed Wall Addition Remodeled Wall
Cavity Framing Isothermal Cavity Framing Isothermal
still air Interior film 0.68 0.68 0.68 0.68 0.68 0.68
sheetrock Interior covering 0.45 0.45 0.45 0.45 0.45 0.45
2x4 wall Framing/cavity R 13 4.2 8.772 13 4.2 8.772
OSB Exterior sheathing 0.5 0.5 0.5 0.5 0.5 0.5
1" foam Exterior rigid insulation 5 5 5
siding Exterior covering 0.61 0.61 0.61 0.61 0.61 0.61
outside air Exterior film, winter 0.17 0.17 0.17 0.17 0.17 0.17
Percent of Clear 77% 23% 77% 23%
Isothermal Plane 11.2 R-value 16.2 R-value
Parallel Path 11.8 R-value 17.4 R-value
2
* R-values in hr∙ft ∙°F/Btu

17. Important Improvements
 Moisture problems alleviated
 Crawlspace/room connection
sealed
 Draftiness eliminated
 Ducts located to conditioned space
 Electrical upgrades simplified
 HVAC system size limited/smaller
 Energy bills reduced
 Comfortable

18. Cantilever Air Sealing Opportunity
• Remove soffit
• Remove existing
insulation
• Add blocking
• Foam seal floor
and wall
• Install insulation

19. Split Level Knee Wall
Air Sealing Opportunity
Attic access unavailable, open wall,
add air barrier and insulation

20. Energy Analysis

21. Whole-House Energy Use
Estimates
Source Energy Source Energy HERS
Year Savings Post-Retrofit Consumption Index
A
House Identifier House Description Built (Mbtu/yr) Reduction (%) Estimate Notes
Jeffry Street Masonry/Frame Split Foyer 1959 56.19 25.44% 96
Dauphine Street Masonry Split Foyer 1956 66.50 28.13% 103 C
Denley Road Masonry Cape Cod 1950 41.23 17.71% 94 B
Pittson Road Masonry/Frame Split Level 1958 78.30 27.90% 99
Goodhill Road Masonry Raised Ranch 1953 64.58 31.32% 86
Middle Road Frame Raised Ranch w/add 1946/ 42.14 18.23% 110 C
Farthing Drive Masonry Raised Ranch 1953 63.11 30.18% 85
Denley Place Masonry Raised Ranch 1950 86.67 38.36% 83
Harrell Street Masonry Raised Ranch w/add 1953/ 22.58 9.24% 90 D
Hathaway Drive Masonry Ranch w/add 1950/ 74.76 24.65% 100
Ivy Glen Road Frame Two-story (2nd Floor add.) 1946/ 107.20 39.12% 80
Napier Street Masonry Split Level 1955 97.39 33.21% 101
Average Savings 66.72 26.96%
A
From tax records
B
HVAC equipment was upgraded in the Pre-Retrofit condition - 92% furnace, 62%PV DHW, 13 SEER A/C.
C
Old HVAC equipment was retained (Dauphine - 8 SEER / 71% furnace, DHW .50); (Middle - 9 SEER / 74% furnace, DHW 63%PV)
D
This house retained the same conditioned square footage in the pre- and post-remodel, but increased from 3 to 5 bedrooms and 1 to 2 baths.
HVAC equipment was not upgraded; 13 SEER, 80% furnace, DHW switched from .53 gas to electric 80 gallon, .86 EF.

22. www.toolbase.org 22

23. Greenbelt Homes, Inc.
 Privately-owned  Pilot Project
cooperative  7 buildings, 28
housing units
development  3 block
 1,600 units  2 frame
 1930’s-40’s  2 brick

24. Pilot Program
 Winter 2010
 Pre-Retrofit baseline
 Install Monitoring Equipment
 Air infiltration
 Temperature/Humidity/
Energy Use
 Humidity
 Summer 2011
 Retrofit building envelopes
 Winter 2011
 Monitor envelope upgrade
 Summer 2012
 Retrofit HVAC
 Winter 2012
 Monitor upgrade package

25. 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

26. Resources
 NAHB Research Center
 Corporate: www.nahbrc.com
 Technical: ToolBase www.toolbase.org
 Remodeling Information & Case Study
 www.toolbase.org/remodel
 Building America
 www.eere.energy.gov/buildings/building_america
 Other Resources
 www.energysavers.gov
 www.energystar.gov/ia/partners/publications/pubdocs/DIY_Guid
e_May_2008.pdf
 www.eeba.org/bookstore/cat-Energy_Efficiency-11.aspx
 http://dsireusa.org/

27. Questions?
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28. 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