This house (1200sqft) I looked at has canned lights. A few lights have a very small gap (1/8th inch). When the exhaust fans are turned on, you can feel the air move from the lights inward, very minimal air movement but enough to notice. The onwer complained of heat loss too and Im assuming it’s through those lights. I took the building science class but don’t really understand enough about negative/positive pressure to give an answer.
Ideas on what is causing the problem and how to remedy them?
Haha nice. I am well aware of the gaskets. I was asking for educational purposes of building science.
‘Can’ lights are prolly the number one or two reason for energy loss through a ceiling. The other would be standrad light fixtures/boxes. Seal them as tight as possible with gaskets, and the vapor barrier in the attic (making sure to follow clearances as determined by the can light manufacturer!).
caulk and seal all around where the can light passes through the sheetrock. There are also plenty of holes and slots in the can itself that also need to be sealed.
I have done that to all such ‘mature’ lights in my home that was built in the early '80s. Has helped for a lot of the conditioned air transfer from my attic to living space and back.
Jacob
Find someone who is trained to do an energy audit using a blower door and infra red imager. A Building Performance Institute certified and trained “building analyst” is the classification you are looking for. The “building analyst” has a thorough understanding of building science and problem solving. Unfortunately, BPI doesn’t have a search method to find their trainees!
Try google in your area; “energy audit”, “blower door testing”
An audit like this well cost around $400 and will identify sources of leakage, amount of leakage, and a lot more information. The auditor will be able to both locate, quantify, and prioritize the leakage sources in terms of ease of repair and effectiveness for sealing the home.
The guess work is eliminated by an energy audit.
Yes, can lights are a huge energy loss in many cases. So are electrical, HVAC, and other penetrations through the ceiling. All ceiling penetrations need to be sealed prior to bringing attic insulation up to current code R-value. That’s the attic part, the first area to improve.
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