- Sill and header
- Windows
- Electrical outlets
- Foundation cracks
- Floor drain
- Service lines (gas pipes, etc)
- Mail slot
- Doors
- Ceiling penetrations
- Exhaust fan vents
- Around the attic hatch
- Chimney
- Fireplace including perimeter
Understanding Air-sealing Prioritization
- Why complete air-sealing in areas to be insulated, before insulating? Before any insulation is added to a wall or roof, air-sealing should be performed within the insulated area. Failure to do so may result in moisture entering the insulated area, reducing insulation effectiveness and resulting in health and durability issues. Air-sealing before insulating is always the highest priority.
- Why in large holes regardless of location? Large holes are a significant air leakage pathway. Large holes are easier, and more cost-effective, to fix than other leakage areas. Large holes present quick air-sealing wins.
- Why on the top floor? In most homes the most significant air leaks are frequently found in the attic/ top floor and basement/lowest floor. This is due to the stack effect: in a heated home, less dense warm air rises and expands, creating a higher-pressure area near the top of the house pushing warm moist air out through air leakage points. Air-sealing at the top of the home eliminates, or at least reduces, movement of moist warm air being pushed through your ceilings and roof, thereby minimizing the stack effect which also pulls cold air into the lower levels.
- Why on the bottom floor/basement? Air-sealing efforts on the bottom floor further reduce the ability of the stack effect to pull cold air into the lower portions of the home.
- Why is it not recommended to only complete air-sealing on the main floor? While air-sealing on the main floor can reduce air leakage and assist in improving comfort on windy days, if air-sealing is undertaken on the main floor without addressing air leakage issues on the top and bottom floors, the work on the main floor will not reduce air leakage caused by the stack effect. Instead, the main floor air leakage may result in a home that is a better funnel for air leakage from bottom to top, caused by the stack effect.
