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
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
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
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.
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/