Yet Another Cycling Forum
General Category => The Knowledge => OT Knowledge => Topic started by: LEE on 21 October, 2009, 12:14:16 pm
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I fitted some 12v Halogen spotlights into a bedroom ceiling and peeled back the insulation to do so.
Is it safe to just roll it back over the top or do I need to allow a protected airspace (risk of overheating/fire?)
The whole country must be full of these things lying under insulation in my opinion, but burning my house down would be inconvenient and costly.
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There is a minimum area you MUST leave space around the fitting otherwise it WILL overheat and your house WILL be filled with smoke - happened to our friends. You can "box" out over the fitting, although I won't recommend any dimensions to you in case I'm wrong. At least you have 12v versions so (I think) less heat generated.
When fittin the 220V ones in my kitchen ceiling I had to ensure space all around (sides and above) and I think it was 100mm.
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They should be fitted with Intumescent hoods. It has been known for people to use terracotta plantpots. The holes in the ceiling also allow all that nice paid for warm air to escape.
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Our house is full of spotlights and a corresponding number of insulation gaps around the holes. Where the loft has been boarded, the lack of ventilation means that the spotlights blow at an alarming rate. I now wish to do the opposite of the OP and remove the spotlights to allow me to put down proper and effective insulation.
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They should be fitted with Intumescent hoods. It has been known for people to use terracotta plantpots. The holes in the ceiling also allow all that nice paid for warm air to escape.
Terracotta conducts heat quite well (don't ask how I know this).
Fit the hoods, like these
http://www.screwfix.com/prods/70589/Lighting-Lamps/Internal-Lighting/Fire-Rated-Downlights/Fire-Hoods/Halolite-Downlight-Fire-Hood-150mm (http://www.screwfix.com/prods/70589/Lighting-Lamps/Internal-Lighting/Fire-Rated-Downlights/Fire-Hoods/Halolite-Downlight-Fire-Hood-150mm)
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I think the answer is... don't fit halogen spotlights... they are a poor solution to the problem of needing light in a bedroom, or anywhere much, really. If you want pretty sparkly lights, then use LED spots, if you need light, then use something completely different that doesn't involve cutting lots of holes through your insulation and ceiling.
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Many years ago I fitted some of these things in my bathroom ceiling. I used a separate transformer for each light and rolled the insulation back over the transformers. One of these failed. An 'expert' told me later that overheating and subsequent failure of the transformer is far from unusual.
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I think the answer is... don't fit halogen spotlights...
No, that's an answer to a different question.
PS. LED spotlights are, currently, either crap or prohibitively expensive.
They (halogens) are a great solution to my requirement of needing bright, directional light and, if I can sort out the insulation over them, there is no issue with cutting a hole in my ceiling/insulation. The lights are only on for a few minutes a day so the wattage isn't an issue for me.
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I think the answer is... don't fit halogen spotlights...
No, that's an answer to a different question.
PS. LED spotlights are, currently, either crap or prohibitively expensive.
They are a great solution to my requirement of needing bright, directional light and, if I can sort out the insulation over them, there is no issue with cutting a hole in my ceiling/insulation. The lights are only on for a few minutes a day so the wattage isn't an issue for me.
You should go for the intumescent hoods then, and add more insulation over the top. They are expensive for what they are though.
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Continuing the theme of answering a different question, we fitted GU10 LEDs to the Boy's bedroom ceiling. They run directly off 230V, using a standard recessed holder.
They were, as noted up thread, bloody useless and expensive. I've replaced them with GU10 compact fluorescents. Much better. Less heat to dissipate than a halogen spot too.
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In answer to the original Q:
Yes you need to leave a space above the lights. it'll be specified on the info that came with the lamps. I fitted 20W low voltage halogens in the kitchen at the last house and they only needed a few cm - plenty of space beneath the floorboards of the bedroom above. And in that situation they were far-and-away the best available lighting solution. Never had any trouble with them.
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NHBC guidance for new homes recommends a hood over recessed fittings. I know this 'cos I had an arguement with the builder of my house, who had simply cut back the insulation around the lights. The hoods that were eventually fitted were basically plasterboard boxes about 6" square by about 10" tall, so they come to the same height as the insulation. They've got 4 holes (about 1/2" diameter) drilled in the top. Seem to work well - bulb (GU10 mains halogens) as good as it every is and no sign of any burning in the attic. Less heat loss than just pulling the insulation back.
The plasterboard boxes don't have to be strong or pretty so they'd be easy enough to make yourself - you could probably get an off-cut of plasterboard for next to nothing from a builder's merchant.
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In answer to the original Q:
Yes you need to leave a space above the lights. it'll be specified on the info that came with the lamps. I fitted 20W low voltage halogens in the kitchen at the last house and they only needed a few cm - plenty of space beneath the floorboards of the bedroom above. And in that situation they were far-and-away the best available lighting solution. Never had any trouble with them.
The loft is mainly boarded. I think I'll just box them off using chipboard flooring over the top and some battens either side. That will stop any flow of cold air and provide an air "buffer" around the lights.
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When you come to sell the house the buyer's survey will note if they're not correctly boxed in.
At least, ours did when we bought our place.
When we boarded the loft, we used a hole cutter to make vents directly above each of the lights covered.
Halogen bulb life can be greatly extended by using a dimmer with softstart, such as Varilight (http://www.varilight.co.uk/) intelligent/touch dimmers. (At least, it has for us)
My employer gave each of us a top-of-the-range LED bulb the other day. Looks just like the real (incandescent) thing. Probably not cheap though.
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My employer gave each of us a top-of-the-range LED bulb the other day. Looks just like the real (incandescent) thing. Probably not cheap though.
That reminds me to tap my dad up for some, he works for a company that does the aircon/lighting fits for shops and factories, the specs for the latest low energy bulbs are good.