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“Air-sealed” can light retrofit vs. Tenmat cover in attic?

I’m planning some air sealing work in my attic. I’ve got a bunch of recessed can lights to deal with, and I had been planning to use Tenmat rock wool light covers on the attic side. This would involve caulking (say, Tremco acoustical sealant) or foaming to seal the Tenmat cover, plus taping up any cuts to allow for electrical wires, etc. After first going into attic, pulling back existing insulation, sweeping the area clean, etc.

Now I’ve seen some LED retrofit lights that are supposed to be air-sealed, e.g., Nicor’s Maxcor DLR56. It has a solid face and a gasket on the back side of the flange. It’s basically a plug-n-play replacement for the current can light, except that it’s a) LED, b) air-sealed (?), c) white, instead of the yellowed plastic of original build. I can probably replace these in a minute, from the relative comfort of my living room, instead of working in the attic.

So, can these retrofit LED recessed down lights (90+ CRI, Cree LEDs, etc) actually eliminate the need for the attic light covers? Am I duplicating efforts to do both?

Thanks for your thoughts.

P.S. I’ve tried to go for higher temperature lights (e.g., 5000K vs. 2700K color), on the theory that anything approaching natural sunlight is better. Alas, I appear to be conditioned to prefer soft white that approximates incandescent. In your experience, is there a big difference between 2700 and 3000? Which would “old folks” likely prefer?

Asked by andrew c
Posted Jun 22, 2014 9:18 AM ET
Edited Jun 23, 2014 4:30 AM ET


9 Answers

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P.S. The can lights are going to be replaced anyway, partly for cosmetic reasons. The real question is whether or not this eliminates (largely?) the need for air sealing from the top side.


Answered by andrew c
Posted Jun 22, 2014 9:31 AM ET


I haven't use the Tenmat covers but if they're made of rock wool, how air-tight can they really be? My guess is that they're fire-resistant, have some insulating value, easy to install, and leak somewhat.

I have used LED retrofit modules on several occasions now, and as far as I'm concerned, they perform really well. Color temperature in the 3000k-or-less range is much more likely to please most folks in their homes, higher temps may be appropriate at work or in commercial spaces.

What you might do is install some of the LED modules and then use a blower door to see how they perform. If the drywall is flat and the gaskets seat tightly, you may not need to do much from above.

FWIW, there are other types of can light covers on the market. I saw some recently that were basically cardboard boxes. And, it is always possible to make your own out of plywood, drywall, rigid foam, etc.

Answered by David Meiland
Posted Jun 22, 2014 1:06 PM ET


On your last question regarding LED color temperature: 2700 and no other!
I'm young enough to be enthusiastic about LEDs but old enough that I can't stand anything that doesn't mimic incandescent. (Needless to say, CFLs never entered my living space.) I've just completed a new house in 100% LED, and couldn't be happier. I think when fully blazing, I'm consuming about 300 watts. I found that the difference between 3000K and 2700K is not subtle, it is gaping. The warmer (2700K) is a very accurate copy of incandescent,, whereas even 3000K looks blue and makes everything feel like a threadbare Kmart aisle. Your impressions may vary; different brands may vary, but I scour the Big Box shelves looking for 2700, which is usually a tiny fraction of their stock.

Answered by Andy Chappell-Dick
Posted Jun 22, 2014 6:11 PM ET


In my opinion, you should never install recessed can lights in an insulated ceiling. If you are going to the trouble of replacing the fixtures, you should replace them with surface-mounted fixtures (for example, track lights or pendants). Even the best recessed can light will leak air and will displace insulation, creating a hot spot in your ceiling.

I suggest that you read this article: Recessed Can Lights. The article notes that not all recessed can lights can be safely capped on the attic side.

If your fixtures are IC-rated, it is safe to install a cap like the Tenmat cap. If they are older fixtures that are not IC-rated, they lack a thermal switch, and therefore can't be capped.

Anyway, if you are pulling the fixtures, I strongly suggest that you choose to go with surface-mounted fixtures.

Answered by Martin Holladay
Posted Jun 23, 2014 5:01 AM ET


Thanks to all for the useful feedback.

Martin: I’ve read all the warnings about recessed can lights, and agree that they should be avoided. I’d never accept them in a new house design. At this point, the budget probably can’t accommodate complete replacement with surface mounts (I’ve got 14 of the blasted can lights!) Since the cans are IC rated, I’m leaning toward keeping them.

I also face another common problem: we have a history of moving frequently. We’ve rarely been in one city for more than five years. (It’s jobs, not necessarily relations with the neighbors ;) ) I see opportunities to make houses more comfortable and more energy efficient, but it’s hard to make those improvements pay off, as most buyers won’t pay for them when they can’t see them. I’m willing to lose some money for increased comfort, but there’s a limit.

Again, thanks for the feedback; I value the information and advice at this website.

Answered by andrew c
Posted Jun 23, 2014 7:49 AM ET


Martin Holliday is my energy efficiency idol, but the question may have been asked in a way that didn't make clear the huge difference in labor between installing a sealed LED device versus replacing the fixture.

I just bought a bunch of these 65-watt equivalent sealed LED device for $15 each on sale at Lowes (Item #: 599032). It takes literally 3 minutes to install them vs hours to replace a fixture, patch the sheetrock, etc. It's like replacing the old bulb with a flat LED panel that screws into the existing socket.

The LED device has a thin foam gasket under the trim ring. My question, along the same line as the original question, is whether I should use some kind of caulk under the trim ring in addition to the foam gasket for a better air seal against the ceiling. Any suggestions for some kind of caulk that would be removable in case I need to replace the fixture? (although the LED is supposed to be good for 50,000 hours)

Answered by Mike Strevell
Posted Oct 20, 2014 6:11 PM ET


Mike, I think you effectively answered your own question. If I had a chance to buy the ones you identified I would have because they are half the price I paid. I wouldn't overly obsess on the caulk unless after installing it there is a noticeable air leak or a gap that is easily visible. I WOULD obsess on one thing: if the can is protruding too close to the roof line it will crowd out insulation. I would seriously consider going by Martin's suggestion for those particular cans. But as far as these lipped led fixtures not being airtight enough, then I just disagree with Martin. (My disagreements with him are actually fairly rare.)

Answered by Eric Habegger
Posted Oct 20, 2014 8:01 PM ET
Edited Oct 20, 2014 8:04 PM ET.


Mike and Eric,
I'm happy to stipulate that installing an LED retrofit kit in a recessed can light is (a) simpler than ripping out the recessed can and installing track lighting and (b) a good way to reduce air leakage through your ceiling. So it's often the best solution to this troublesome issue.

However, an LED retrofit kit won't do much about the problem of thin insulation above the recessed can.

Answered by Martin Holladay
Posted Oct 21, 2014 6:14 AM ET


I've tested the Tenmat covers, and they do leak a fair bit. My best guess is that placing them over a non-ICAT housing reduces cfm50 by about half of what and ICAT housing would - just under 10 cfm per fixture on a housing that I would guess was leaking 15-20. LED retrofit kits are great, but probably not code compliant if you intend to blow insulation directly on a non-ICAT housing.

Answered by Jesse Smith
Posted Oct 21, 2014 6:16 PM ET

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