This homeowner called us hoping that we would be able to help her with the part of her home that had a cathedral ceiling. The “air boundary” of the top of a home is the drywall ceiling. Under this plane is “inside”, and above it is “outside”. Can lights are a hole in the ceiling. Since can lights have holes in their metal housings, they allow air the homeowner paid to heat to leak out of the home. Since they are in a cathedral ceiling, workers can’t access the top of them to cover them. Typically, insulation is kept away from can lights, so they also cause a problematic gap in the insulation. Warm indoor air leaking into the roof assembly can cause condensation, mold and rot in the roof. Results - less comfortable home, higher fuel and electric bills, mold issues.
The bulb and trim rings were removed and the air leaks in the can light housing were sealed with fire caulk to stop air leaks. The gap between the drywall and can light was sealed as well. The trim was put back and we changed the bulb from an incandescent bulb which burns at up to 380˚ to an LED bulb which burns at 135˚. This not only lowers the cooling load in the summer but made it possible to “dense pack” our cellulose insulation into the cathedral ceiling around the can light fixture. Air leaks were stopped and the ceiling (roof) can be insulated without a gap for the light. Results - A more comfortable home that’s easier to heat and cool, lower fuel and electric bills.
Can lights - before
These are the can lights before we removed them. There are air leaks around them, and fiberglass batts behind them -- so air from outside leaked directly into the home.
Using Fire Caulk
Our employee is fire caulking around the can lights to air seal safely.
Sealed Can Light
This is one of the can lights
Can lights - after
These are the sealed can lights - complete with energy-efficient LED bulbs!