Where to Inspect Air Leaks
Many air leaks and drafts are easy to notice and to feel — like those under the doors or around the windows. But there are some hidden or less visible openings that are major sources of air leaking.Attic, Basement And Crawlspaces
Openings and cracks in the basements, crawlspaces or in the living space are a source of air leaking into the house, while openings and cracks in the attic cause air leaking out of the house. These different air leakage locations, at different heights, cause leakage flows (since warm air tends to rise and cool air to fall).
The attic is the ideal place to stop many air paths and to solve some important leakage problems.
Small Cracks And Openings
Small openings and cracks in windows and doors and in plenty of other locations, should be fixed. Small gaps do not mean small energy losses. On the contrary.
Strategic Places To Examine
The image shows the main and most common sources of air leakage, and the places to inspect.
Pay attention to:
– Plumbing penetrations: Bath Tubs and Plumbing Penetrations Sealing.
– Wiring penetrations and electrical outlets and switches: Air Sealing Electrical and Ventilation Openings
– Chimney penetrations
– Walls: missing sheathing and the tops of interior partition walls, where they intersect with the attic space;
– Foundation walls: along their tops, where they encounter the sill plates and band joists.
– Floor cavities: namely if the floors extend beyond foundation walls.
– Attic: Air Sealing Attic Penetrations (especially at access doors or built-in cabinets)
– Ceilings: recessed lights and fans, even if the ceilings are insulated.
– Soffits (dropped ceilings): especially above bathtubs and cabinets. Air Sealing Soffits/Dropping Ceilings
The larger openings, responsible for most air leakage in common wood and steel frame homes, are related with construction flaws. The image is a good illustration of that very fact.
The image also stresses the importance of the building envelope (smaller square): the red-orange strong line that surrounds the outer walls and the ceiling and floors should involve a strong and continuous air-barrier, often missing in most buildings.