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Air sealing low profile LED lights

Sergio D | Posted in General Questions on

I have a 1600 sqft single story house in Huntington Beach, CA (US Climate Zone 3; CA Climate Zone 6). It currently has 36 recessed lights throughout the home. These lights have the conventional 6″ remodel housings. I want to replace these with the following low profile lights so that I can better insulate my attic. My only problem is that I don’t know of a good way to properly air seal these lights.

Does anyone have a recommendation on how to air seal these types of lights? Are the clips and gasket enough to provide a good air seal? The attic is a traditional vented attic, and I think I will be forced to insulate at the ceiling instead of the below the roof deck.

https://www.homedepot.com/p/Commercial-Electric-Slim-Baffle-6-in-Color-Selectable-New-Construction-and-Remodel-Canless-Recessed-Integrated-LED-Kit-91479/310114087

Just to clarify, these lights do not require housings. I will be removing the existing large metal housings, and installing these lights in the opening. Unfortunately, all the recessed lights are 6″ in size.

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Replies

  1. Expert Member
    Zephyr7 | | #1

    I don't know how well those fixtures are sealed themselves, but I wouldn't trust the clips and gasket to make much of a perimeter seal. In my experience with fixtures like these, the clips aren't very strong. The best way to seal is probably two pieces of rigid foam on the attic side, with the middle piece caulked to the drywall and having a hole the size of the fixture in the middle, and the top piece being sold and glued onto the one with the hole to make a sandwich-like assembly.

    Next best is probably some rope caulk under the perimeter flange of the light fixture. Rope caulk will seal better than a foam gasket with weak clips, but it won't do anything to help with any air leakage through the fixture itself.

    Bill

    1. Sergio D | | #7

      Thanks for the advice. I thought about building some type of box over the light fixture. However, building 36 of them and properly sealing them will be really time consuming and daunting. This might be needed anyway since I plan on having blown-in cellulose insulation installed in the attic, and I will need something to hold back the insulation when I have to replace a light.

  2. fcserei | | #2

    The clips are quite stong, and the gasket is pretty effective if you cut the drywall hole to the right size. I had no problem passing the blower door test with these lights.

  3. Expert Member
    Akos | | #3

    Same here with 4" slim LEDs, the clips are very strong and seal well to the drywall.

    No leaks during blower door test.

    I haven't tried any 6" ones but looks like the same construction.

    1. Expert Member
      Malcolm Taylor | | #4

      The electrician I use has a neat set up on his drill. He cut down a juice container and mounted it so it collects the drywall dust from a 4" hole saw. Very clean crisp opening.

    1. Expert Member
      Malcolm Taylor | | #6

      Ah - that's where he got the idea. I guess he was too cheap to buy one.

  4. Sergio D | | #8

    It is interesting that people have said that they have passed blower door tests with these types of lights. Normally are you dealing with batt or blown-in insulation against these types of lights?

    I plan on having cellulose blown-in up to the ceiling joist height (2x4) and then a layer of batt insulation running perpendicular. How can I stop the blown-in insulation from raining down on me when I'll eventually have to replace a light? Will the weight of the insulation cause the light to move away from the ceiling?

    I wish there was a manufacturer that makes a 6" recessed light housing that is only 3.5" tall. The shortest I was able to find is 5.5"

    1. Expert Member
      Akos | | #10

      These are not canned lights but the slim ones as the link bellow. Canned lights leak like a sieve.

    2. Mark Adle | | #18

      How can I stop the blown-in insulation from raining down on me when I'll eventually have to replace a light?

      This is the question I keep running through my head. Will I have 15” of blown in cellulose falling on me when changing the light? Being on a ladder changing LEDs on a 10’ ceiling isn’t ideal. Nor is going in the attic, brushing around 15’ of cellulose trying to find the LED disc to change out either.

      Hopefully someone can answer this.

      1. Walter Ahlgrim | | #19

        The LEDs themselves should last for 20 years or so at 3 hours a day before they fail IE loose more than 30% of their brightness. With luck the power supply built into the fixture will last that long.

        I like to buy fixtures that fit on the 4 inch standard round electrical box so I can air seal the box and wires and replacement fixtures are going to fit the standard box when they do fail.

        Walta

  5. PBP1 | | #9

    I think I have around 50 low profile 6" LEDs, similar to what is in the link (not identical, more like https://www.homedepot.com/p/Commercial-Electric-Ultra-Slim-6-in-Color-Selectable-New-Construction-and-Remodel-Canless-Recessed-Integrated-LED-Kit-91477/310114092?MERCH=REC-_-pipinstock-_-310114087-_-310114092-_-N ). 30+ of them are installed in a shed roof/metal exterior and flash n batt interior covered with tng. They are quite low profile so they really don't disturb the batt (no impact at all on flash, i.e., foam). The clips are strong enough and there's a foam gasket. Even if they did "leak" a bit, where's that going to go? From the tng to the batt? "Strong enough" may not be strong enough to hold up the electrical box if it is set directly on top of the wafer. One thing to note, will you have them on dimmers? If so, there may be a faint buzz. Hmm "I think I will be forced to insulate at the ceiling instead of the below the roof deck" - can you flash n batt at the roof? (or just foam it?) Must it be vented? (https://www.buildingscience.com/documents/digests/bsd-102-understanding-attic-ventilation) Any ducts running in attic?

    1. Sergio D | | #11

      My air ducts are in the attic, and the air handler is in the living space. I asked the local building department if I can convert my attic to an unvented attic and was told that all "concealed spaces" must be vented. Also to keep things simple, I'm thinking that I'll follow Option B in Title 24 (see attached).

      1. PBP1 | | #13

        You might want to check Energy Vanguard website on spray foam and/or fiberglass, I just saw something about fiberglass with netting. There's this link too: https://www.energyvanguard.com/blog/fiberglass-still-number-one-insulation-home-builders At the moment, I'm looking to insulate a Mitsubishi SEZ.

      2. Expert Member
        Zephyr7 | | #15

        If you convert your attic to a conditioned attic, it will be connected to the interior of the building (the living space) and will no longer need to be vented to the outdoors. Chances are the building department didn’t fully understand what you were asking.

        Note that batts on the attic floor do not contribute to air sealing at all. Any leaks from the lights will leak air right through the batts too.

        Bill

  6. James Howison | | #12

    The 4" version fit, together with their little transformer box, inside these sort of air-sealing boxes: https://foursevenfive.com/instaabox/ Tape those to the drywall, slip the romex in. Assuming you have access from above. You could push those boxes up through the hole for the lights, but I don't think you could tape it onto the drywall from below.

    This box much tougher and probably large enough for the 6" ones.

    The gasket seems decent, but I do see some light from above on the ones I have above the garage (without the Instaaboxes), not sure if the light comes around the gasket or through the body of the units.

  7. Alan Afsari | | #14

    If this is a retrofit, our plan may not not work for you. You would need to mount junction boxes behind (over the drywall).

    I have airfoil round junction boxes (http://www.airfoilinc.com/) and Eaton/Cooper surface mount leds.

    There is a cavity to spray foam where the wires enter the box and there is a flange for air sealing the drywall to the box.

    Each box was about $4 or $5 and each surface mount was $
    about $20 (http://www.cooperindustries.com/content/dam/public/lighting/products/documents/halo/spec_sheets/hr-smd6-td518242en-sss.pdf)

    We r in the insulation phase of new construction. We are in climate zone 5 and have (too many) cathedral ceilings and a low pitched roof (1.5/12).

    Our roof is not nvented - flash and fill (ccspf and fiberglass bibs) insulation (as described elsewhere on gba - thank you Martin Holladay).

    This seamed like a cost effective way to get air sealing without relying on the seal of the surface light to the ceiling.

    Alan

    1. Expert Member
      Malcolm Taylor | | #16

      Alan,

      I think y0ur strategy makes a lot of sense.

  8. Jacob O'Reilly | | #17

    The Instaabox looks very promising for canless LEDs.

    If you had access to the attic, what kind of adhesive would you use to seal the lip to the sheetrock ceiling (Silicone, Acoustic, construction adhesive, etc.?)

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