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I would like to convert my downlights to LED. However, the LEDs I've found have holes around them to let the air though. I've been told this is for ventilation purposes and blocking these holes or putting insulation over them will cause the LED to overheat and shorten their lifespan.

Changing from a halogen to LED, I'm going from about 35W to about 5W so there's certainly benefit there but I'm wondering whether it's still worth it because these holes are going to create drafts and increase my heating costs.

How much heat is generally lost due to unsealed downlights? Is it a negligible amount or is it comparable to the energy savings from converting to LED?

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  • How much draft is there in your ceiling?
    – THelper ♦
    Aug 19 '14 at 12:48
  • THelper : I'm concerned about the heat escaping through those holes into the attic
    – dizzy
    Aug 19 '14 at 12:56
  • I understand, I'm just wondering how much of a problem this could be. In my house I didn't notice any draft whatsoever in the space above the downlights we have installed. Also, halogen needs cooling too (in fact LED runs at cooler temperatures than halogen), so my first guess would be that the heat loss is similar.
    – THelper ♦
    Aug 19 '14 at 14:16
  • @THelper - don't know - I haven't been up to the roof to check. You're right that my halogen downlights aren't completely sealed either - there's more holes for LEDs though. But maybe the difference is negligible. Still, it would be interesting to know how much heat escapes from downlights in general and whether it's a concern - I can't seem to find any research about it.
    – dizzy
    Aug 19 '14 at 23:44
  • The exact numbers would very much depend on the local situation; how big is the space above the downlights, how much insulation in your roof, which type of LED, etc. Also, I don't think it is much of a concern (but admittedly I'm not entirely sure).
    – THelper ♦
    Aug 20 '14 at 6:19
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Read your local electrical code carefully. Usual requirement is that a recessed ceiling fixture must have no flamalable material in X inches. If in a ceiling/attic space there is supposed to be an air seal box around the fixture enclosure itself.

The code may also allow lower clearances for lower wattage lamps.

The concern is that waste heat will gradually char wood that is nearby. As wood chars it's ignition temperature lowers. You can get a situation where a lamp put in today will start a fire in 5 years.

Since hot air moves upward, a recessed fixture tends to collect a LOT of heat.

Both LED and fluorescent lights are so much lower wattage that fire hazards are usually minimal. You may be able to either block the holes, or replace the recessed fixture with one that doesn't permit air flow. At this point you may be able to increase the insulation at in that space.

Caution: Maintain the integrity of the vapour barrier. If you don't, you will get warm humid air moving up through the lamp, and condensing in the attic space potentially causing mildew and rot.

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