Owens Corning research quantifies leakage rates for 17 common house joints and openings.
In an ideal world, a new-home builder would have an unlimited budget for constructing a properly sealed building envelope that renders air leakage obsolete. Unfortunately money is tight and the typical single-family detached residence has nearly one mile of joints and openings that leak air and allow moisture, cold drafts, and noise to enter the home. The builder with a limited budget can’t seal every nook and cranny, so the question is, which leaks matter the most?
Conceptual graph of the biggest bang-for-the-buck approach to air sealing where the most effective joints to seal are those that offer the largest amount of enclosure tightening with the least amount of linear footage of applied sealant.
Top plate-to-attic—The red arrow depicts the inward leakage path.
Recessed lights can leak an appreciable amount of air between the light housing and mounting flange (red arrow 2), and between the mounting flange and dry wall (red arrow 3). Leakage through the light housing is fairly tight as required by many building codes (red arrow 1).