Air sealing attic floor & top floor ceiling lights
Hi all,
We’re doing a remodel on our Seattle-area craftsman with a vented attic and are working on developing a tight(er) building seal.
I’m a bit stumped on the best approach to our top floor ceiling lights. They are a mix of recessed cans and surface mount lights (attached to j-boxes through the ceiling drywall). We will be replacing them all.
In my ideal world, we’d pull out the existing lights and j-boxes, patch the drywall, and use a 475 monowire gasket to seal around a single wire penetration to the newly installed ceiling lights.
It seems that this should be possible with low-voltage LED lights that either have a driver/jbox located in the attic with a low-voltate wire that runs through the gasket & ceiling to the light.
However, these are surprisingly hard to find. My Internet searches haven’t really yielded much. I also spent 30 minutes with a specialist at Seattle Lighting and came up empty-handed.
Is there a different / better approach I should be considering? Or do folks have products they’d recommend here (low-voltage lights)? Or am I stuck trying to air seal around the existing j-boxes?
Thanks in advance!
Dave
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Replies
for the cans I would replace with something like this:
https://www.lowes.com/pd/Halo-White-LED-Remodel-and-New-Construction-Recessed-Light-Kit-Fits-Opening-5-in/1001772158
They have a gasket at ceiling and are pretty air tight otherwise. I don't think you will get much air leakage through them.
for existing jbox lights I would just seal the junction box with either tape or foam. I'm assuming you have access to the attic.
They also make fire covers, some of which are airtight you could buy to cover them. you could also build a couple of sealed gyp or ply boxes that fit over them and seal them to the ceiling gyp with caulk or tape
The usual approach to sealing the cans is to "box over" the cans using rigid foam (or a purpose-made insulating "hat") on the attic side of the ceiling over each fixture. This works well, but is labor intensive if you have a lot of lights to seal. You can also replace the cans with the newer IC-AT cans, but those aren't exactly "air tight" either, despite their ratings.
For the J-boxes, I usually just tape the holes on the attic side and then put a layer of spray foam over the assembly to seal things up. This is fast and easy (relatively), but you have to have access to the attic side of every box.
I'm not a fan of the low voltage fixtures with remote ballasts. I think that when those fixtures inevitably fail in the future, you'll be stuck replacing the entire system because the original system will no longer be available. With octagon J boxes, you're using a standard that is over 100 years old already (for the electrical boxes), so it's pretty likely you'll be able to find replacement fixtures in the future that can mount in those same boxes that you already have installed. Chances are pretty good you'll always be able to find bulbs or conversion kits for recessed cans too.
Bill
Thanks both for your thoughts!
Would you argue for new recessed cans that I air seal or jboxes for lights intended for new locations?
J boxes will be easier to air seal, but somewhat more limiting in terms of light fixture options.
Bill
I've just gone through a similar exercise, except my recessed light were in a vaulted ceiling with no insulation above them. With a considerable amount of effort I was able to demo and remove the old recessed lights that were leaking air like a can full of holes, and have put an insert into the hole in the ceiling created for the can light with a jbox mounted in the insert. This was then sealed. To the jbox I have surface mounted thin flat LED lights. This option gives you a pretty tight air seal and gives you flexibility to can light fixtures in the future.