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Old 03-27-2011, 11:35 AM   #1
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Covering LEDs with insulation

Hi all,

We bought a house this past fall with minimal attic insulation. There are also ~ 15, 4" recessed lights that use halogen lights and are not IC rated. We want to blow insulation into the attic. Our current plan is to replace the halogen bulbs with LEDs and keep the receptacles. The local Home Depot electrical guy told us to just put metal tape over any holes in the can to prevent insulation from getting inside, and then cover them with as much insulation as we want; so long as we use LEDs, the heat build-up should be minimal. We have 2 questions:

1. Is this logic (switch out halogens for LEDs and then tape up the cans) valid? It seems to make sense, but considering how often we get conflicting advice from Home Depot/Lowe's folks, it would be nice to get independent confirmation.

2. Will there be a problem with covering up the transformers, or can those safely be blanketed with insulation as well?

Thanks for any advice!


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Old 03-27-2011, 12:12 PM   #2
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Use trepidation when taking advice from the helpful people at HD, Lowes, Menards, etc. While they may mean well, I have seen far to many instances of poor or outright wrong advice being given.

If the fixture is not IC-rated then you cannot use it for that application. Period. You cannot use the argument that the selection of lamps will make a non-IC fixture appropriate for use in an IC application. Remember that when you have moved on, the next owner may want to replace the LED lamps with an incandescent.

When I install IC-rated fixtures, I usually use metal HVAC tape to fortify what has already been provided with the fixture (which is usually gone or coming off by the time I open the box). You can probably apply this technique to non-IC fixtures to prevent air leakage/moisture migration from occupied to unoccupied spaces (my AHJ prefers that this approach is taken to all metal switch and device boxes that are installed in exterior walls). But in the end, you cannot (or should not) cover the cans will insulation.


Well, now, there's what's right and what's right and never the twain shall meet.
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Old 03-28-2011, 09:16 AM   #3
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Thanks for your input. I knew the HD way sounded too good to be true. I guess we'll go with the boxes over each can, or try to track down the elusive 4" IC-rated units. How about the transformers? Can those be covered with insulation?
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Old 02-10-2012, 04:47 PM   #4
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My experience is that if you put LEDs into 12V fittings (in place of 50W halogens) and you have 'electronic transformers' converting your supply power to 12V the transformers will die as their design requires a minimum load and a single LED is far below that minimum.

See discussion in LEDs kill downlight transformers
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Old 02-10-2012, 10:16 PM   #5
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If you use compact fluorescent or LED lamps, you could put insulation over the fixtures without overheating. However, it's not legal and not a good idea, since someone later could easily install incandescent lamps again and overheat the fixture.
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Old 02-10-2012, 10:33 PM   #6
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I do not know how many LED bulbs are actually rated to used in the recessed luminaire I know .,, I know you will say EH ? but with LED the hottest part will be in the driver area.

The driver is kinda the same as ballast in flourscent bulbs are but differnt meaning and that one reason why you have to double check the labels to say if can used in recessed can or enclosed luminarie.

The heat will kill either one ( screw LED or screw in CFL ) and I have see them failed before so that soemthing you may want to check it out.



The answer will be based on NEC ( National Electrical code ) or CEC ( Cananda Electrical code ) or ECF ( Electrique Code France )
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