How do you air-seal recessed lights that you can’t access from above?
I’m currently chasing air leaks in my 1850 brick farmhouse after a recent blower door test. We have five recessed lights in the kitchen and five in bedroom above the kitchen. Obviously I can’t access the cans in the kitchen to retrofit some sort of “hood”, and I actually can’t access the ones above the bedroom either. The cans are a mix of types – some are the remodel type, some are new-construction type, some are rated for contact with insulation, and some aren’t. The only thing I want to do is air seal them until we gut and renovate the kitchen, and do a major lighting overhaul in the bedroom. So my question is this: Can I seal the slits inside the cans with either foil tape or fire-rated spray foam? Thank you in advance for any help with this.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
Chris,
Here is a link to an article that you may want to read:Recessed Can Lights.
The best way to deal with these lights is to remove them completely. In their place, install an airtight electrical box, and then install a different type of lighting fixture -- track lighting, pendants, or some other type of surface-mounted fixture. A good lighting showroom will have lots of options. Of course, if you go this route, it's important to install insulation after removing the can, and it's important to pay attention to airtightness.
If you don't want to do that, you can install an LED retrofit kit that will cut down on air leakage, but won't address the problem of the thin insulation layer above the can.
Martin,
Thanks for the response, I do appreciate it, but it doesn't really answer my question. Perhaps I wasn't clear enough with my question. I know that the best thing to do is to get rid of the lights. That's not an option right now, nor is replacing them. I have other projects going on in the house so I'm looking for a solution that will get me through the winter as there are design concerns as well (I'm married to an interior designer so fixture style and location are as important to her as having them air tight are to me... and you know what they say: a happy wife...). I've seen videos wherein energy contractors fill the gaps w/in the cans with fire rated spray foam and I'm wondering if anyone on here has an opinion about whether that is a safe practice or not. Thank you.
Chris,
我希望你会读第一article I linked to. In that article, I wrote, "Older fixtures had holes in them and depended on air leaking through the ceiling to stay cool enough to be safe. The manufacturers of these older fixtures warned installers that the fixtures should never be covered with insulation."
In other words, if you see holes in the can, the holes are there for a reason. As stupid as it sounds, the designers of these cans wanted them to be leaky, because they are designed to dissipate heat by encouraging air flow. Plugging those holes might be hazardous.
Got it. I apologize, Martin. I assumed it was the article I'd already read but apparently it wasn't. I should have checked the link first...Thanks very much for your response.
Chris,
No apology necessary. Good luck!
You might consider one of the LED replacement bulbs that include the trim. These are nearly air-tight at the ceiling boundary at least. Some have gaskets under the trim ring for better sealing. You'd still lose heat from convection, but at least the air leakage would stop.
Chris: why do you need to air seal the kitchen lights? Isn't the bedroom above the kitchen conditioned space?
Stephen,
My house is balloon framed so the kitchen ceiling joists / second floor floor joists are directly connected to the exterior walls. Most of the house is packed with cellulose, though it seems the kitchen / upper bedroom has fair to poorly installed fiberglass batts instead and I can safely assume no one created an airtight band to isolate the kitchen ceiling. My assumption is confirmed by a blower door test that revealed a decent amount of air loss through the cans, and you can feel the draft near the lights even without that technology. Sealing them is only diverting the air loss, I realize, but w/ a house as old as ours my main focus is improving comfort level while trying to have some impact on the building envelope. I've sprayed the rim joist and added gaskets to the wood storms which has cut down on drafts tremendously (as well as heating bills). My intention was to add a air-sealed rigid foam "top plate" to seal the gap between walls and exterior brick, but the roof pitch and deep eaves and depth of cellulose in attic make that job nearly impossible. Unfortunately the part of the house w kitchen and master bedroom isn't accessible from the attic because of the way someone remodeled it years ago. Until I gut the kitchen, which is a good year away, I want to try to minimize those drafts. sorry for the lengthy reply.
Chris: thanks for the explanation. As the owner of a house built during the Washington administration, I recognize the difficulties associated with trying to improve the energy efficiency of a vintage house. The seemingly random placement of posts and beams in my exterior walls makes any assessment of how well it was insulated by a previous owner difficult.