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Enclosure or caulk around thin LED recessed lights?

hertzr | Posted in General Questions on
Hi all,

I know this may make some cringe, but I am interested in installing 12 qty Halo HLB 4” recessed LEDs in my home’s second floor (see product link below). We have a combination of wall and ceiling fan/lights throughout the second floor now, but it is just too dark at night for our liking.

Like most folks, am concerned with maintaining a continuous ceiling air barrier as the lights will protrude into the attic.

I asked the manufacturer, Eaton, if the lights would function properly being housed in small plywood and rockwool enclosures mounted on the attic side. The enclosures will include a fluid applied WRB and have a 2- or 3-in air gap around all sides of the light. They felt this approach was excessive because the lights are sealed, include a gasket, are E283 compliant, and should be caulked to the ceiling. They said the lights would function either way though.

What are your thoughts? Build the enclosures or trust the gasket/caulk?
Thanks in advance!

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  1. Expert Member
    BILL WICHERS | | #1

    The lights will be sealed well enough to meet the spec for “airtight”, but they usually still leak. I’d still build boxes if you want maximum air tightness. I’ve not been very impressed with the gaskets, either, especially the ones for LED trim title 24 compliance. It’s nearly impossible to get a good seal with any of them.


  2. seabornman | | #2

    I take it you're using this light because you have existing ceilings? The very similar Halo lights that fit in a 4" ceiling box are more amenable for air sealing.

  3. davidl256 | | #3

    Can these gaskets be caulked to form a better seal between the gasket and drywall. In other words, would the caulk damage the gasket?

  4. walta100 | | #4

    When shopping for LED lighting the efficiency of the LEDs vary greatly. The one you selected is very poor at only 65 lumens per watt.

    Take a look at something like this it mounts to a standard electrical box that you can air seal tightly and look almost the same at 85 lumens per watt it is just OK, I like to find something over 100 L/W


  5. Expert Member
    Akos | | #5

    When I was getting an blower test done on an old house with a number of those in the ceiling, I was surprised to see how well they seal. With the blower running didn't see any leakage around them.

    They work much better than "air tight" cans.

    The spring clip they use on those is pretty beefy. Provided the light can sit flush in the drywall and clearance on the top for both clips, they seal pretty well. Maybe not passive house levels.

    Use common sense on the number of them especially if going onto a cathedral ceiling.

  6. exeric | | #6

    I had a blower door test of my home done (twice) recently and it contains 20 old fashioned can lights. I installed them before the electrical box recessed lights came out. The whole house air exchange per hour came out to 2.25 ach 50. I'm pretty happy with that since my house is approximately 75 years old and I did all the renovations for tightness.

    The key is to create a smooth flat surface where the gasket or seal will be. It just requires attention to detail. There is no other mitigating technology, such as boxes over them in the attic, just air tight rated and insulated covered rated cans. You should be fine with more modern leds such as electrical box surface mount ones.

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