In condensation in the attic marc rosenbaum suggested that ceiling fans recessed lights and other fixtures be sealed to reduce air leakage into attics.
How to seal light fixtures in attic.
Apply self adhesive foam weatherstrip tape to the top edge of the stop.
The gap between a fixture and the drywall can be easily sealed with caulk but leakage through the fixture itself can be substantial.
Even though light fixtures fasten tight to the ceiling there s enough of a gap to let air flow through the many holes in and around the electrical boxes they re fastened to.
You can stem the flow of air and money by air sealing your light fixtures from the inside with just a roll of painter s tape a can of spray foam insulation and a tube of painter s caulk.
Sealing a ceiling electrical box caulk the wire knockouts and the ceiling penetration.
Clear away any residual insulation at the ceiling area around the light by hand or using the brush.
Apply a generous bead of the spray.
In this video mike guertin shows how.
Seal the attic access weatherstrip the attic access hatch or door.
Carry the box spray foam and a utility brush to the attic.