Habitat for Humanity Montgomery County, MD

Existing Home Retrofit ProjectMixed Humid Climate

NAHB Research Center

Residential Building Energy Efficiency Meeting July 2010

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Project Goals - HFH

Deliver 12 fully renovated homes to clients

Affordability, Enhance safety, Improve durability, Lower the energy cost, Adhere to schedule and

budget

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Project Support – NAHBRC/BA

Review for durability & efficiency opportunities – as available

Obtain “test-in” data where possible Detail efficiency enhancements Identify products/methods for increased

efficiency Document process as implemented Obtain “test-out” data where possible Model energy savings Catalogue of construction details for retrofit

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Unique Construction Process

Coordinate volunteer activities daily Segment work into “bite-size” portions Instruct/Train workers Organize materials per segment &

availability Complete the house for immediate sale

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12 Homes in ProjectHouse Year

Built Style Foundation Framing Conditioned Floor Area Notes

Dauphine Street 1956 Split Foyer Walkout Block 2,098 sqftJeffry Street 1959 Split Foyer Walkout Block 2,067 sqft

Harrell Street 1953 Ranch Basement Block 2,431 sqftWood frame addition w/ crawlspace foundation

Hathaway Drive 1950 Ranch Crawlspace Block 1,256 sqftWood frame addition w/ crawlspace foundation

Denley Road 1950 Cape Cod Basement Block 2,575 sqftDenley Place 1950 Ranch Basement Block 1,872 sqftFarthing Drive 1953 Ranch Basement Block 2,148 sqftGoodhill Road 1953 Ranch Basement Block 1,872 sqft

Middle Road 1946 Ranch Basement Frame 1,760 sqftWood frame addition w/ crawlspace foundation

Pittson Road 1958 Split level Basement Frame/Block 1,872 sqft

Ivy Glen Road 1946 Two Story Basement Frame 2,052 sqft 2nd floor wood frame addition

Napier Street 1955 Split Level Crawlspace Block 1,764 sqft

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All Homes 50+ Years Old

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Common Approach by HFHMC

Remove interior wall finishes from exterior walls Upgrade electric including rewire Replace most plumbing and all fixtures Assess HVAC equipment and ducts for minimum

necessary replacement Add/Increase insulation in foundation, above

grade walls and ceiling Replace windows

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Initial General Recommendations Identify critical air sealing areas Broom sweep and HEPA vacuum all areas of the home after demolition to improve effectiveness of air sealing for

worker safety Perform air sealing before insulation For attics and crawl spaces, confirm that passive ventilation is adequate or bring up to current code for moisture

control Replace windows with the highest efficiency that budget will allow and install per manufacturer's recommendations For HVAC systems, perform an early-on evaluation of the gas furnace, air conditioner, duct system, water heater, and

chimney vent for proper operation and combustion safety; consider these individual components together to cost effectively optimize efficiency;

Install direct vent, minimum 92% AFUE gas furnaces and 14.5 SEER cooling systems and size in accordance with ACCA Manual J/S

Seal all ducts Relocate supply and return ducts from exterior walls to floor Ensure low resistance return air paths for all rooms (for example, ducted returns or baffled transfer grilles) Add MERV 8 minimum filtration Install draft stops for chimneys (metal and masonry) at floors and ceilings using metal and fire-rated caulk. Install metal insulation shields in the attic to provide clearance between chimneys (metal and masonry) and insulation. Install programmable thermostats Duct kitchen and bath exhaust fans to the outdoors Install direct vent or power vent water heaters, insulated hot water piping, and add low flow faucets, shower heads,

and water closets Install ENERGY STAR refrigerators, dishwashers, and clothes washers Install Energy Star lighting fixtures and/or bulbs Confirm downspouts adequately direct rain water away from house, ground is graded away from house, and sump

pumps are operating properly

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Recommendations Achieved Identify critical air sealing areas Broom sweep and HEPA vacuum all areas of the home after demolition to improve effectiveness of air sealing for

worker safety Perform air sealing before insulation For attics and crawl spaces, confirm that passive ventilation is adequate or bring up to current code for moisture

control Replace windows with the highest efficiency that budget will allow and install per manufacturer's recommendations For HVAC systems, perform an early-on evaluation of the gas furnace, air conditioner, duct system, water heater, and

chimney vent for proper operation and combustion safety; consider these individual components together to cost effectively optimize efficiency;

Install direct vent, minimum 92% AFUE gas furnaces and 14.5 SEER cooling systems and size in accordance with ACCA Manual J/S

Seal all ducts Relocate supply and return ducts from exterior walls to floor Ensure low resistance return air paths for all rooms (for example, ducted returns or baffled transfer grilles) Add MERV 8 minimum filtration Install draft stops for chimneys (metal and masonry) at floors and ceilings using metal and fire-rated caulk. Install metal insulation shields in the attic to provide clearance between chimneys (metal and masonry) and insulation. Install programmable thermostats Duct kitchen and bath exhaust fans to the outdoors Install direct vent or power vent water heaters, insulated hot water piping, and add low flow faucets, shower heads,

and water closets Install ENERGY STAR refrigerators, dishwashers, and clothes washers Install Energy Star lighting fixtures and/or bulbs Confirm downspouts adequately direct rain water away from house, ground is graded away from house, and sump

pumps are operating properly

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Project Lesson 1: Assess/Prioritize

Assessment procedures for energy and durability enhancements need further development

Air-sealing procedures for volunteers (i.e. DIY market) requires more detail

Case for increased efficiency HVAC retrofit needs much more research

Unique and/or older house features require specific solutions (i.e. foundation, wall & roof insulation, duct assessment and sealing, etc.)

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Clear Improvement: Wall Insulation

R 4.7 original to R 20 retrofit

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Other Wall Improvements

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

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Air Infiltration Details Needed

Special air sealing attention needed in this group of houses: Floor and foundation wall intersection (no rim), Rim band areas, Ceiling and wall intersections, Wire and pipe plate penetrations, Sloped ceilings, Balloon-framed gable end walls, Cantilevered floors, Gable walls adjacent to main house walls in split-level designs, Attic hatch covers, Chases/chimneys, Wall sheathing, and New openings created by the retrofit, such as:

Door and window opening, Through-wall penetrations Story-to-story penetrations

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Wall Air Sealing Challenges

Interior block

Exterior brick

Crawlspace vent

Floor

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Cantilever Air Sealing Challenges

• Remove soffit• Remove existing

insulation

• Add blocking• Foam seal floor

and wall• Install insulation

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Split Level Knee WallAir Sealing Challenges

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

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Chimney Chase Air Sealing Challenges

Large air leakage beside chimney to attic

Large air leakage beside chimney to crawl space

Air seal to attic whenchimney removed

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HVAC Retrofit Challenges

Cost – Leave the original system in place

if still in good working order Duct sealing –

No provision for improving system due to contractor-volunteer issues

Sizing – Additional cost, application of

result not relevant in some cases (original system left in place)

Improvements – Highly dependent on mechanic

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Mixed Results - Infiltration and Ducts

House Test-InInfiltration Duct Leakage

Test-OutInfiltration Duct Leakage

CFM50 ACH50 ACHnatCFM25 total/

exterior CFM50 ACH50 ACHnatCFM25 total/

exteriorDauphine Street 3/12/09 2680 9.6 0.48 438 / 20 NA

Jeffry Street 3/12/09 2612 9.5 0.475 888 / 182 NA

Harrell Street 9/3/09 could not test 4/22/10 3856 11.90 0.595 580 / 83

Hathaway Drive 9/3/09 4184 25 1.25 416 / 172 5/26/10 2985 17.80 0.891 590 / 184Denley Road no NADenley Place no 3/23/10 2984 12.00 0.598 848/0

Farthing Drive no 3/5/10 3043 10.60 0.531 667 / 31

Goodhill Road no 2/4/10 2530 10.10 0.507 380 / 25

Middle Road no 2/17/10 1889 8.00 0.402 958 at 9.6 PaPittson Road no NAIvy Glen Road no 4/13/10 1761 5.90 0.265 1400 / 98

Napier Street 2/4/10 4850 20.6 n/a 5/26/10 2307 9.80 0.545 369 / 28

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Overall Energy Savings

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.

Whole-house energy improvement range - 9% to 38% with an average savings of 27%Based on performance, nearly all of the homes achieve HERS Index of 100

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Estimated Cost & Savings

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Summary

HFHMC process for renovation has unique aspects that require special planning

Initial assessment of older homes requires specific attention to uncommon features

Exterior wall improvements add large benefit Air sealing challenges require detail and

material specification esp. for DIY market Energy performance level of current code

achievable Basic project goals of HFHMC met

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Initial Needs for Future Projects Better assessment procedures based on house

design and location More thorough HVAC analysis Integrated analysis of whole-house investment

opportunities Highest efficiency vs. cost

Product options and application details Design details Prioritized details per renovation level

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Questions?

Amber WoodProgram Manager, Energy Efficiency

NAHB Research Center301-430-6309

awood@nahbrc.com