I have a client with 16) 4" halogen recessed light fixtures in the attic.
I'd like to cover the cans with air tight, fire rated boxes.
The plan is to blow cellulose insulation over the boxed fixtures.
My concern is about lamp-generated heat being trapped in these air tight, insulated boxes.
I'm wondering if the trapped heat might cause a lamp or fixture failure.
Any thoughts or experiences on this topic out there?
If you can't talk them into replacing with IC rated...
Look into Tenmat - those are designed (& tested) to keep adequate spacing & resist fire
The tops should not be covered with additional insulation
Yes it can as they have a heat sensor which should shut off the fixture - if that fails the other issue becomes fire (thus the Tenmat recommendation & you clean up around the light)
All good points brought up. My advice is not to leave the lights. When you said halogen I think problem. If they were just standard non IC rated lights I would say box them with appropriate material, put in a CFL.
We box around non IC light all the time and have not had issues. We go 3" clearance.
As it turns out, we have 10 Halo 99RT housings with Halo 998P Eyeball trim in the kitchen. The trim takes a PAR20 bulb.
And 6 JunoTC44R housings with 12 volt MR16 halogen swivel base trim in the living room.
The Halo housings look to be air tight, while the Juno housings are definitely not air tight.
I've always thought that it would be okay to install an air tight box over a non-AT housing. But now I am not so sure. The non-AT housing seems designed to dissipate heat through its vents. If I cover the can with an air tight box, it seems like I am trapping more heat around the fixture than it was designed for. Even if I am not insulating over the top of the box. That's a pretty serious liability when you start thinking fire safety.
Permanently derating the wattage of the fixture with CFL or LED seems like the next likely solution. But some clients can't stand the harsh white of CFL's. And yes, even the new Cree LED modules have a harsh white compared to incandescent.
So it seems that my remaining option is to swap out the non-AT Halo cans with an ICAT product like the Halo H99. $30/each material cost. It looks like I can reuse the existing Halo eyeball trims in the new ICAT cans.
For the Juno cans, I can swap them out for Halo H99 as well. I'll have to buy 6 more of the Halo 998P Eyeball trim, at about $30 each, since I won't be able to reuse the existing 12 volt halogen trim in this transformer-less can.
Add a couple hours of labor do the swap and make the cans really air tight. And we are looking at close to $200 a pop. This can get pricey for a can-happy home.
By the way, I am not an electrician, but I am keen on figuring this non-ICAT can thing out. It seems to come up on a regular basis during attic air sealing and insulating upgrades.
If fthese are OLD cans, I would suggest you really want to replace them with IC Airtight --- first step. The plastic insulation on the lamp sockets in the old cans loose their flex and have oftenn become brittle with age. Since the goal is to extend the useful life on the house - replacing those cans - does both. I have replaced cans in house built in the 60's and nearly every one had insulation on the wires that was failing. (Move wire and chunks would fall off.) This problem occurs EVEN if the insulation wasn't over the cans. The plasticizers just don't hold up with time.
The old cans had a much larger heat problem than most realized.
If you do replace the cans with IC AT, make sure you read the instructions carefully, gaskets are often required to meet the airtight ratings -- and sometimes the gaskets are special order. :-(
$12.95 is a bargain for the can... bet it didn't include the trim... that probably adds another $25 :-(
The other thing I've seen is that old homes might have cans that were for smaller bulbs. 5" cans -- and they can be quite pricey. It is actually far less expensive to go with a 6" can, and use the trim to reduce the opening to the 5" bulb size.
The new IC cans will also have thermal cutoffs built into them. If you manage to install a light bulb that is larger than it is rated for... and it produces lots of heat... you will get the nice on -- off -- on -- off blinking of the lights when the thermal protection kicks in. Few old cans had thermal protection built in...
Bachi, I've asked electrical contractor friend about the cost of the replacing cans on houses before -- and he figured $125-$150 plus material for each can... that figures in the costs of labor, permits, inspections, etc... into the pricing.
Last winter at one of the ACI conferences in the NW, I believe efi.org was showing some surface mount LED's that looked identical to a 6" recessed can (from the room view). But it was perhaps 0.5" think. The driver was a 12V supply that I suspect could be mounted under the panel in a deep box. No more crawling in the attics with these lights. And the air leaks would be gone - yet they would look like recessed cans.
Yes, that definitely does not include the trim but those vary very widely. Basic baffles are cheap but you should price a vapor proof trim for an H99. (i believe it was 4" cans we were discussing) I'm going to have to check out those LED's. I've been using more and more of them and they have a lot of advantages if you can get a warm enough color temp.