Affordable Housing Focus on Efficiency

Remodeling & Passive House Approaches

Greenprints Conference March 14, 2011Amber Wood, Manager Energy Programs

NAHB Research Center

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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.

Department of Energy Programs

Building America DOE’s residential research &

development (R&D) program

Builders Challenge DOE’s energy efficiency

certification for homes

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

High Performing Home Goals

“High Performing Homes” that are Energy efficient Durable Comfortable Healthy to live in Safe

Affordable

In other words . . . Green.

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 savings

Tax credits and rebates

Source: 2007 Buildings Energy Data Book, Table 4.2.1., 2005 energy cost data

Whole-House Design

Design/Implement energy efficient solutions

Work through implementation issues Technical product/system designs Details Process (quality management)

Simulations/Analysis Cost optimization

Building America Integration

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Safety($-$$$$$)StructuralCombustionLeadAsbestosMoldMoisture

Building EnvelopeDurabilityMoisture Bulk Vapor DrainageAir Sealing Insulation

SystemsHeatingCoolingRight-SizedDucts VentilationDehumidification

Hot WaterPiping

AppliancesLightingMELs

RenewablesSolar Electric (PV)Wind

START HERE

COST

Whole-House Re-Design

ENERGY EFFICIENCY SAVINGS POTENTIAL

Montgomery County Habitat for Humanity

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

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

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

Clear Improvement: Wall Insulation

R 4.7 original to R 20 retrofit

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

* R-values in hr ft∙ 2 °F/Btu∙

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

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

* R-values in hr ft∙ 2 °F/Btu∙

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

Cantilever Air Sealing Opportunity

• Remove soffit• Remove existing

insulation

• Add blocking• Foam seal floor

and wall• Install insulation

Split Level Knee WallAir Sealing Opportunity

Attic access unavailable, open wall, add air barrier and insulation

Energy Analysis

Whole-House Energy Use Estimates

House Identifier House Description Year BuiltA

Source Energy Savings Post-Retrofit

(Mbtu/yr)

Source Energy Consumption Reduction (%)

HERS Index

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.

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Greenbelt Homes, Inc.

Privately-owned cooperative housing development

1,600 units 1930’s-40’s

Pilot Project 7 buildings, 28

units 3 block 2 frame 2 brick

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

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

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_Guide_May_2008.pdf www.eeba.org/bookstore/cat-Energy_Efficiency-11.aspx http://dsireusa.org/

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Questions?

Thank You!

Amber WoodNAHB 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