Indoor Air Quality

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Weatherization and Indoor Air Quality U.S.
Environmental Protection Agency
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Weatherization and Indoor Air Quality

• Determining the Homes Condition
• Weatherization Options for Homes
• Weatherization Impacts on Indoor Air Quality
• Determining the Right Amount of Ventilation
• Targeting Air Sealing

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Determining the Homes Condition

• Energy audit of home performed
• Customizes energy-efficiency upgrades
• Upgrades prioritized for cost effectiveness
• Blower-door testing of air leakage in and out of
  homes outer shell
• Duct testing of loss of conditioned air from
  forced-air system
• Visual inspection and other diagnostic tests

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Weatherization Options for Homes

• Air Sealing- caulking and weather-stripping to
  reduce leakage of 1) outdoor air into the home
  and 2) heated/cooled (conditioned) air from home
• Insulation added to attics, walls, and/or floors
  to increase resistance to heat flow
• Window replacement to reduce air leakage
  thermal losses/gains

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Weatherization Options- Continued

• Old heating equipment replaced add
  high-efficient equip. setback thermostat
• Repair ducts Seal leaks and repair failed
  connections
• Hot water heater add insulation to tank and
  pipes replace with efficient unit add low-flow
  shower heads
• Fans in warm climates ceiling, attic, etc.

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Weatherization Impacts on Indoor Air Quality

• The house is a system air sealing and insulating
  can change how a house operates
• Sealing and tightening the homes envelope
  (reducing air leakage) can
• Make existing problems worse
• Create new problems
• Problems can cause discomfort or may be lethal

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Weatherization Impacts on IAQ - Continued

• Stack-effect altered and reduced make-up air
• Spillage/Back-drafting of combustion products
  (e.g., carbon monoxide) from atmospherically
  vented furnaces, hot water heaters, wood stoves
  and fireplaces
• Reduced natural ventilation impacts
• Increased moisture/mold, other biologicals
• Increased chemical pollutant levels
• Increased odors
• Effects of gas leaks magnified
• Less fresh air for occupants

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Determining the Right Amount of Ventilation

• Test In-Test Out Blower-door testing
• Before alterations to establish leakage of
  envelope and target sealing upgrades
• After energy upgrades to ensure adequate
  ventilation for indoor air quality
• Establish Minimum Ventilation Requirement (MVR
  or Building Tightness Limit, BTL)
• Compute MVR with ASHRAE 62-1989 or ASHRAE 62.2
  (latest version)

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Targeting Air Sealing

• Sealing/weather stripping conducted
• Target for blower door reading usually between
  pre-weatherization test result and calculated MVR
• State programs often determine the target test
  result differently
• Test atmospherically vented combustion
  appliances/equipment for spillage/back-drafting

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Additional Resources

• EPAs Indoor Air Quality Web site
• www.epa.gov/iaq
• EPAs Climate Change
• www.epa.gov/climatechange/
• ENERGY STAR Home Improvement
• www.energystar.gov/homeimprovement
• EPAs Ventilation for Homes Web page
• www.epa.gov/iaq/homes/hip-ventilation.html
• EPAs The Inside Story A Guide to Indoor Air
  Quality
• www.epa.gov/iaq/pubs/insidest.htmlIntro