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Community and Q&A

Heat loss, can lights in cathedral ceiling

JWBDSR | Posted in Energy Efficiency and Durability on

The information about replacing or retrofitting can lights with LED fixtures has been really helpful. However, I have a cathedral ceiling with what I think are standard can lights, with a diameter of 7.5″ within the can, and about 9.5 ” total diameter including trim–the ceilings are about 18′ high so I am having a difficult time getting to one to carefully measure.

I cannot find anywhere residential can light LED retrofits for this size. I’ve looked at what Cree offers, as well as Home Depot and Lowes, and they all max out at 6″.

Any recommendations on where I could find something of this size, or any other ideas? Thank you in advance.

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  1. User avatar
    Dana Dorsett | | #1

    Sounds like you have R40 / BR40 bulb recessed fixtures in an R30 / BR30 sized world.

    You won't find them on the shelves in box stores, but LED versions of R40 / BR40 bulbs are available online. Do a web search on R40 + LED, you'll find all sorts of retailers (including box stores) selling them over the web.

  2. JWBDSR | | #2

    Thank you very much for your response. The R40 / BR 40 bulbs are easy to find, but I'm still striking out on finding R 40 / BR 40 size recessed LED fixtures and/or LED conversion kits. Thanks for any ideas you might have.

  3. User avatar GBA Editor
    Martin Holladay | | #3

    Here is a retrofit LED fixture that is 7 inches in diameter -- described as a can light retrofit:

    Maybe you should get a high step ladder so that you can get a good measurement of your existing can lights, to determine whether this 7-inch-diameter fixture will work.

  4. JWBDSR | | #4

    Mr. Holladay, thank you for the link. I've read your articles through this web site and they are very helpful. Thanks.

  5. Jeremy Archer | | #5

    I have used these LED fixtures on a few occasions they come in 4, 6, and 8 inch diameter and very easy to install and sit fairly flush with the ceiling.

  6. Norman Bunn | | #6

    Jeremy - how well do these LEDs air seal?

  7. Jeremy Archer | | #7


    I have never installed these in a ceiling with a vented attic above and conducted a blower door test. So far i have used them in a basement and in soffits. In my opinion they provided a very nice tight fit. The fixture comes with a foam gasket that can go between the light and the ceiling material and it is held in place by two fairly tight spring loaded clips that pull the light towards the gasket. I don't see why you couldn't add some caulking as well to increase the seal but i would refer to the manufacturer to be sure.

  8. JWBDSR | | #8

    Thank you for the LED fixture recommendations. One more question--is anyone aware of an 8" led retrofit gimbal fixture--one that adjusts so the light will shine downward with a sloped ceiling? Again, there are many 6" available, but I struggled to find an 8". Thank you.

  9. JWBDSR | | #9

    Thought I’d try once more, as I continue to strike out with the local lighting company. I have six 8 inch cans in a sloped, cathedral ceiling. Thanks to all of the input here, I finally found 8” retrofits that will fit in the can and fully cover the existing ceiling opening. However, since I’m working with a sloped ceiling, I need them to point downward, as with a gimbal or eyeball type of fixture, as opposed to straight out. For this, I can find absolutely no options, either by internet searching or through the local company that’s been quite helpful. If anyone is aware of any 8” LED retrofits that will point downward, I’d sure like to know about them. Thanks in advance.

  10. Steve Knapp CZ 3A Georgia | | #10

    It looks like you can find gimbal lights in smaller sizes. Consider having a local shop make up some "goof" rings to reduce the size of the opening. I had an issue with the hole size on my project, and the lighting contractor suggested the ring approach. (It not an uncommon issue apparently.)

  11. Andrew C | | #11

    Regarding gimbals -
    I found that the LED retrofit lights that I use have a much larger beam angle than the recessed lights that they replace. I currently have several standard LED retrofit fixtures mounted in sloped ceilings, but I think the coverage is better than before with the down-facing recessed lights. Rephrasing, if the slope of the ceiling isn't too steep, you may be able to get away without using gimbals because the replacement lights have larger beam angles.

    The only issue that I have is that when the original canned lights were installed, the circular cans were cut flush with the sloped ceiling, creating elliptical openings. The steeper the ceiling's slope, the harder it is to get the round (flange) of the LED light to cover the ellipse.

  12. Jonathan Lawrence CZ 4A New Jersey | | #12

    To echo what Andrew said, some of these flush mount, pancake style LED's have beam spreads as high as 120 degrees, and you will get all of that in a high ceiling.

  13. Bennett G. | | #13

    An alternate approach would be to seal the holes in the cans with foil HVAC tape, seal around the perimeter to the drywall with tape or caulk and use LED edison base bulbs in your current eyeball trim.

  14. Justin Brown | | #14

    I did install the gasketed LED retrofits, and during a blower door, was pleased to find that they really didnt leak any significant air. If you can find them in your size, go that route.

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