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Recessed Lights Are Evil

By In Recessed Lights On February 1, 2011


I love recessed lights, but even the best ones create a ridiculous amount of heat in attics, which can lead to ice dams.  Until I started performing infrared inspections in attics, I never quite grasped how much heat recessed lights contributed to attics, but now my eyes are wide open.  The main problem I find with recessed lights is that they’re not insulated well enough; on a recent home inspection in Maple Grove, I found a home with forty-six recessed lights sticking up in to the attic, along with some wicked ice dams on the roof.

A standard recessed light will stick up in to the attic about seven inches.  If an attic has fourteen inches of  loose fill fiberglass insulation, how much insulation does that leave on top of the recessed light?  Hang on, let me get my calculator…

At any rate, there’s far less insulation above recessed lights than anywhere else in the attic, and these are the areas that get the hottest, so they should really have more insulation than anywhere else in the attic.   Unfortunately, that never happens.  The combination of minimal insulation and hot light fixtures shows up clear as day using an infrared camera.

Recessed Light in attic with IR overlay

The images above show how much heat is leaking through the insulation above an IC rated, airtight recessed light with a 65-watt incandescent bulb.  IC rated means that it’s safe to have insulation directly in contact with the light, but it’s not synonymous with airtight.  You can usually tell if a recessed light is airtight just by looking inside it; if there are a bunch of holes inside the housing, it probably isn’t airtight.

Non-airtight recessed light

If you can see light pouring through on the attic side, it’s definitely not airtight.  All of these little holes in the housing are passageways for heated air to escape in to the attic; they’re called attic bypasses.

Non-airtight recessed light

Having said all this, I don’t think recessed lights are truly ‘evil’, but they sure can cause a lot of problems, and there seems to be very little understanding of this in the building trades.   Here’s what you can do to prevent problems:

If you plan to install recessed lights that are going to protrude in to your attic, make sure they’re airtight, IC-rated lights.  After the lights are installed, be sure to double down on the amount of insulation above the lights; you’re gonna need it.

If you already have airtight recessed lights in your home, you probably need way more insulation installed on top of them.  This is usually quite simple to do, but without an infrared camera, it might take a little time to locate all the lights.

If you already have non-airtight recessed lights sticking up in to your attic, don’t worry; there’s a fix for this.   Simply construct an airtight box out of rigid foam insulation, and ‘glue’ it together with spray foam.

Insulated Box

Now place this airtight box over the offending recessed light in your attic, and use a bunch more expanding foam to seal it up and make it completely airtight.   Not only will this prevent air leakage from around the light, but it will dramatically increase the insulation level above the light.  While the box pictured below is the ugliest box I’ve ever seen (I built it), it’s still very effective at preventing heat loss.

Insulated box over recessed light

If constructing and installing insulated boxes throughout your attic seems like too much work, you could always replace any standard incandescent light bulbs with compact fluorescent lights or LEDs; they produce far less heat, they’re easy to install, and you’ll start saving money on your electricity bills.

Reuben Saltzman, Structure Tech Home Inspections – Email – Maple Grove Home Inspections

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About the Author

Reuben

Reuben is a second generation home inspector with a passion for his work. He grew up remodeling homes and learning about carpentry since he was old enough to hold a hammer. Reuben has worked for Structure Tech since it was purchased by Neil in 1997, and is now co-owner of the company. Reuben’s favorite customers are the ones who have a lot of questions; he grew up thinking he was going to be a school teacher because he enjoyed teaching others so much. In a sense, that’s a lot of what home inspections are about, so Reuben truly does what he loves. Reuben has an A.A. degree in liberal arts and has attended most of the Building Inspection Technology classes at North Hennepin Community College. Reuben and his wife are the proud parents of two young childen, Cy Alexander and Lucy Nicole, and have a German Shepherd named Stanley. With two young children Reuben doesn’t have much free time, but he still tries to play disc golf as often as possible during the summer. Reuben lives in Maple Grove, MN. Professional Qualifications / Memberships: *ASHI Certified Inspector *President, ASHI Heartland Chapter *Member, Minnesota Society of Housing Inspectors (MSHI) *Licensed Minneapolis Truth-in-Sale of Housing Evaluator *Licensed Saint Paul Truth-in-Sale of Housing Evaluator *Licensed Maplewood Truth-in-Sale of Housing Evaluator *Licensed Hopkins Truth-in-Housing Evaluator *Licensed Robbinsdale Point of Sale Evaluator *Affiliate Member, Southern Twin Cities Association of Realtors

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119 Comments

  • Elie 11 MONTHS AGO

    Excellent. Much appreciated and Happy New Year.

  • Justin 11 MONTHS AGO

    Hi Reuben, Thanks for your post's, very informative and appreciated. I have a multitude of recessed lighting issues I am dealing with. In my upper level of our ranch home we have 64 recessed lights. Some going into the attic with room to build boxes and some so close to the soffet or on on the outside (corner of the house) of a tray ceiling - virtually impossible for a human to get access to this space with our 4/12 roof pitch. I am converting to the Cree LED 6.0 W 40Watt equivilant on some and most to the LED 9.0 Watt 60 watt equivilant as in Connecticut we get a great deal on the energy efficient lighting through a state program. That said, I have tested temperatures inside the recessed lights and they have come to only 95 F - I have tested with the fire-block greatstuff by completely encapsulating a couple of my IC rated 7'' hats with amazing success - I did this in an open area as my thought is to try and do this to some extent on the inaccessible ones from the living space with strategically placed holes around the existing ceiling penetrations. So - my questions for you are about foaming directly to the IC rated hat with the aforementioned fire-block type foam - I know it is not fire proof but is it in fact more fire resistant and withstand temps in the neck of the woods I should be concerned with? Thanks again for your comments and input! Justin in Connecticut

    • Reuben Saltzman 11 MONTHS AGO

      @Justin - my guess is that you'd be fine, but it's definitely just a guess. If you want an official answer, you'd probably need to contact the spray foam manufacturer, the light bulb manufacturer, the light manufacturer, and the Mythbusters.

  • Elie 11 MONTHS AGO

    I am finishing a basement. i have IC-rated cans in the ceiling. i am trying to sound-proof the room as much as possible, and was thinking of building a box of soundproof drywall over the top of the cans (i have QuietRock). There is not much clearance between the top of the cans and the floorboards above. There is probably just enough to build the drywall box and then put 3" insulation above the box. The question is, is there any fire risk (or other problem) if i build a box of quietrock with just maybe about one inch clearance above the top of the IC can?

    • Reuben Saltzman 11 MONTHS AGO

      @Elie - if they're IC rated lights, no issue.

  • Yask 12 MONTHS AGO

    Hi Reuben We have recently installed LED recessed lights that does not require insulation box. We are unable to access the attic area (split level home) so electrician put holes in the ceiling from the house to fix the lights. Now we are facing increase in the Gas bill for heating. We compared last years bill to compare this year's bill and its higher why is it so? please guide.

    • Reuben Saltzman 12 MONTHS AGO

      @Yask - If you're experiencing higher heating bills, it's probably because the cost of gas went up or outdoor temperatures are lower this year than they were last year. Installing a few recessed lights wouldn't make a noticeable difference in your heating bill.

  • Pam 1 YEAR AGO

    I have 10 Halo can lights from 1987 that are in my attic and light the bedrooms of the top floor. I have a problem with insulation debris coming down through them as well as ten perforations into my attic. They are not IC or AT and I would like to make them both so I can put insulation over them. I would also like to put LED bulbs in them. I have already put LED floods in the cans in my kitchen and am very happy with the light there. But, do the new cans come with a socket that works for LED bulbs. It looks like the new Halo 6" cans (HALO H71CTWB 6" air tite) on Amazon talk about incandescents. I assume this is OK, but am not sure as the LED bulbs seem heavier. I don't want to go to all of the work of changing to new cans and then not have them be right.

    • Reuben Saltzman 1 YEAR AGO

      @Pam - I see no reason why LEDs wouldn't work, but if you want to be 100% sure, check with the manufacturer.

  • Jesse 1 YEAR AGO

    Reuben, Years ago, I installed 4" halogen non-IC recessed housings in 3 rooms of my house. Originally, I made simple tin covers that kept the ceiling batt insulation away from the fixtures, after reading about overheating. Air leakage into the unconditioned attic space wasn't thought of back then, but it is now. I bought new ICAT low voltage MR16 housings, but due to compatibility issues with the trim rings, I'd like to return the ICATs and build either rigid foam or drywall boxes over the air-leaking non-IC existing housings. My concern is overheating the lamp/risk of fire issues. Can you comment on the use of self-made boxes?

    • Reuben Saltzman 1 YEAR AGO

      @Jesse - as long as you maintain the required distance from the light, you shouldn't have any problems with overheating / fire issues.

  • Love MN Winters 1 YEAR AGO

    I've been planning on upping the insulation in my attic from R-30 to R-49/60. In anticipation of this I started looking at the 4 can lights I have in my living room. They were not IC rated so I replaced them with 5" IC rated cans. We're going to blow in the new cellulose this weekend so I wanted to test how the IC rated cans were doing with the current insulation levels I have. I turned them on for several hours and then went up in the attic to see how hot they were. While they didn't burn my hand, they were very hot to the touch. Should I be concerned about this? Will the addition of 10" of insulation on top of the cans make the problem worse? I was debating building a box around the IC fixtures just to be sure I didn't have any issues in the future.

    • Reuben Saltzman 1 YEAR AGO

      @Love MN Winters - no, this isn't something to be worried about. Recessed lights with incandescent bulbs get very hot to the touch. It's normal.

  • Carl 1 YEAR AGO

    Thanks very much, just built 4 of these for the Bazz Cube lights I installed, but cannot use a standard mounting box for to protect them from the insulation. This will also keep my R value up, so you've done me a double service as this cost me a total of 40 dollars, with enough for at least 2 more boxes.

  • nick 1 YEAR AGO

    hi, i installed 6" commercial electric can lights in my basement. they are rated for 65 watt incandescent BR30 bulbs according to the sticker on the can. So i put a 65 watt flood bulb in each can but these seem too hot and are melting the baffle/trim. whole basement smells like melted plastic. what gives?

  • Kevin 1 YEAR AGO

    Good information. I have non IC 6 inch pots. I like the foam or drywall boxes and keeping it 3 inches away.....however is that only if fixtures have a safety switch as some non IC do.

  • ryan 1 YEAR AGO

    I want to install 4w and 7w leds on the 2nd floor ( the ceiling is insulated). the leds have a heatsink that goes in the ceiling. do i need to make a box around the led? or move the insulate away from the led or just place the insulated over the led? P.S I live in canada it does get pretty cold

    • Reuben Saltzman 1 YEAR AGO

      @ryan - I recommend you consult with the manufacturer of the light that you're installing the bulbs in.

  • carey 1 YEAR AGO

    that's all great that every one wants to use sm foam and spray foam but you have to remember that it is a combustible. and if anything you should be using is 5/8 type x drywall and fire stopping . just saying . there are fire codes to think about.

  • Kirk 1 YEAR AGO

    I knew a man who had recessed lights in his kitchen. After a half hour they would go on and off by themselves. They were cycling on the thermal protector in the housing. Fixing the problem required removing the insulation for 6 inches around the can.

  • Charlie 1 YEAR AGO

    Abigail Putnam: I just want to put my two cents in. I live in MN. Although we do not have cathedral ceilings, we have sloped ceilings that get down to less than a foot of clearance between the ceiling and the roof in spots. What I did was use low profile, airtight, IC rated cans (much shorter than standard). On top of that, I picked LED recess kits. They contain the trim and bulb in one unit, and they look fantastic.The ones I used were "Commercial Electric", there are many other brands. I wonder if Reuben would grace us with his take on that combination, IC, Airtight, Low Profile cans along with LED kit. Very low heat, 11 watts per light.

  • KK 1 YEAR AGO

    Hello Rueben, I have three non IC rated recessed lights. What is the best way to air seal those? or should I put IC rated lights in attic and then air seal? What would be safer and cost effective approach?

    • Reuben Saltzman 1 YEAR AGO

      @KK - The safest and best way to air seal and insulate would be to replace the lights with IC rated airtight lights, and then install insulated boxes over them. The most cost effective approach would be to just install the insulated boxes.

  • Abigail Putnam 1 YEAR AGO

    Thank you for the advice. We live in Massachusetts; so yes, similar to Minnesota. We are not sure what we will do for lighting in the shower, but we will completely avoid recessed lights. Thank you!

  • Abigail Putnam 1 YEAR AGO

    Hi Reuben, This post was very informative for us as we are renovating our home. Our challenge is that our home is old with very low ceilings. For our master bedroom and bath, we ended up eliminating the attic above that half of the house, to create a cathedral ceiling. Thus, the ceiling in these 2 rooms is the actual roofline. We were warned that we should not put recessed lighting in these rooms because of the production of heat. Do you think your insulated box suggestion would work in these spots? Or would the LED lights be ok? Or should be completely eliminate the idea of any recessed lighting in these rooms and go with some other style? Thanks!! Abigail Putnam

    • Reuben Saltzman 1 YEAR AGO

      Abigail - where are you located? If it's anything like Minnesota, I'd skip the whole idea of putting recessed lights in your cathedral ceiling.

  • Reuben Saltzman 1 YEAR AGO

    @Neil - Who is Greg? If the insulation contains asbestos, you should either leave it alone or have it professionally removed / abated before doing work around it. Otherwise, what's the problem?

  • Reuben Saltzman 1 YEAR AGO

    @Paul - who is Greg?

  • Neil 1 YEAR AGO

    Hi Greg, I have recessed lights in my great room. Only 4 of the them, it's an open to above room. I find there is not enough light. So I am in the process of adding another 5 lights there. I am told by some that I should not disturb the insulation, and other's say there is no worries of adding more and no issue with disturbing insulation. what are your thoughts? thanks Neil

  • Paul 1 YEAR AGO

    Hey Greg, In the process of renovating my first home, it's a 2 storey century old home. I have the whole thing torn apart and have finally completed the demo phase and am begining my wiring. I have a flat roof spanning about 30'x14' the trusses are all true size 2x8. I have specd' out closed cell spray foam insulation for the entire home (including the flat roof) which will give me a value of R30 and leave me roughly a 3-3.5" gap between the finish insulation and the drywall. We plan on zero clearance pot light that will be wired prior to insulation being sprayed. Any thoughts on this? What if any are your recommendations for type/style or model or pot light? Since the house is fully stripped now is the time for me to do this properly and I want to make sure that I'm not over looking anything. Thanks, Paul

  • Charlie 1 YEAR AGO

    Hey Reuben! I read this article a little late. I had just installed 4 new construction, IC rated cans in my kitchen that were not airtight. I was just about to install 13 remodel cans that were the same, IC but not AT. I have a sloped ceiling, and there was maybe a foot of space above these cans and my roof.So I pulled out the new construction cans, returned the remodel cans, and got ones that were both airtight and low profile. I was going to go with CFL's, but they were pricey, looked terrible, and required special dimmers. I ended up going with LED trim kits, and I have to tell you, I couldn't be happier! The cost was about the same as a quality dimmable CFL plus a decent trim. Now I am using 117 watts vs. the 1275 I would be using with incandescent, and 408 I would have used with CFL! And they look GREAT, you would never know they were LED. Thanks for the article, I think you saved me a TON of time, aggravation, AND money!!! I can't imagine if I went ahead with what I had.

  • Craig 1 YEAR AGO

    We're looking into having more insulation blown into our attic (Oklahoma). We currently have 16 non-IC rated cans installed in our house. The main problem for IC-rated replacements or putting insulated boxes over them for me is that two of the rooms they're in have vaulted ceilings, making some of them very hard to access without removing sheetrock (one of them completely inaccessible from what I can tell and at least 3-4 that would require basically crawling to and from them for every bit of the work). In regards to the one that is inaccessible, is the only "official" solution to rip out the sheetrock and replace the non-IC can with an IC-rated? We had thought of putting all LEDs, but that doesn't alleviate the future issue of putting incandescent bulbs back in later obviously.

    • Reuben Saltzman 1 YEAR AGO

      Hi Craig, That's the only solution I know of. - Reuben

  • louieg 2 YEARS AGO

    You provide a great alternative for the invasion of or escape of energy. keep in mind that LEDs do produce heat. Many use heat sinks to remove the heat.This heat if accumulated can cause damage( premature failure of the electronic circuitry. I suspect that if higher/longer stacks were provided then heat accumulation would be more minimal. I plan to use your solution to air infiltration but enlarge the box.

  • dalton 2 YEARS AGO

    You might want to see if the Styrofoam ice coolers are flammable first ...before placing them over your hot light boxes. Great idea if their flame resistant.

  • eddie gonzales 2 YEARS AGO

    no need to build a styro-foam box, just go to walmart and buy an inexpensive styro-foam ice cooler,,,just the right size....done

  • LT Dupre 2 YEARS AGO

    I have an office in Louisiana (no ice damming to worry about here). My law partner won't let me leave three can lights in our foyer because he was told twenty years ago that if there is any insulation touching the top of the can, that it could combust. Our cans are not airtight but our office is less than ten years old. Is there a risk to leaving the lights on overnight (looks great from the road at night)?

    • Reuben Saltzman 2 YEARS AGO

      The risk is probably quite minimal. If there's a concern, install LED bulbs. They create far less heat. If you're going to be leaving them on overnight, you should do that anyways.