How much heat loss actually occurs through open back down lights?

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Wolf555

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#272021 5-Jun-2020 19:14

Last winter I redid all the ceiling insulation in our house. We have open back down lights so I left a gap around them as your meant to.

Last I checked it would cost almost the same as all the insulation to replace all of our fittings with closed back LEDs. Our current bulbs themselves are leds, but not the fittings.

How much heat are we actually losing through the downlights and gaps in the insulation? We really don't have a couple of grand to spend on replacing them. Has anyone had any experience with those cosydomes instead? Or am I maybe expecting too much gain from replacing them?

robjg63

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#2499280 5-Jun-2020 20:33

How many down lights do you have?
What diameter is the cutout hole?
LED down lights don't cost too much.

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timmmay

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#2499282 5-Jun-2020 20:38

I read a consumer article a few years ago that said from memory that four downlights that weren't insulated over something like doubled the heat loss from the room, which is the same as saying you had to pay twice as much for power to heat it. I had put downlights into my house, I had them replaced with standard ceiling lights and it helped. This was before LED units you could insulate over were available.

elpenguino

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#2499284 5-Jun-2020 20:42

There's losses from incomplete insulation coverage but there's also open gaps around some halogen downlights. That leads to draughts which are hard to quantify.

Suffice to say they're bad.

The sooner you improve things the longer you benefit.

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MikeAqua

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#2500517 8-Jun-2020 12:26

Those open down lights let through a lot of heat.

When we moved into our current house it had 30 something open backed down lights. If I put my hand beside one when the house was being heated the upward airflow was very obvious.

During the first winter we found the difficult to heat with (it was built in 2010 and has two heat-pumps). I swapped all the downlight fittings for LEDs that can have insulation abutting and fully covering them. This took me about two hours.

There was an immediate and noticeable difference in ease of heating. No regrets.

Mike

raytaylor

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#2504200 13-Jun-2020 18:28

I get into attics quite regularly and yes you can definitley feel the heat coming up through them on a cold day when the attic isnt very warm.

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htweedie

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#2504252 13-Jun-2020 19:11

I've found them to be quite significant.

A number of years ago we struggled to keep the living room warm in our 1909 villa (although it is pretty large). It was renovated in 2000 so supposedly had full insulation so the problem didn't make sense.

I assumed it was the downlights so went into the loft to find that part of the insulation hadn't been installed (which accounted for part of the problem), but saw that the spider webs were running vertically over the downlight holes due to chimney effect from the downlights (given the halogens burn at 200 deg C the heat creates a chimney that sucks air our of the room).

Installed new insulation and insulation cones over the halogens from firepro (this was before suitable LED's were available). Both made a significant difference.

https://firepro.co.nz/product_datasheets/112/ff130.pdf