Heat output of lightbulbs

rbulph

I understand that non-fluorescent lightbulbs are not very efficient and that about 80-85% of the energy used by them is converted to heat rather than light. Given that, is it such a bad thing to leave a light on in winter when you don't need it at a time when you would have your heating on? The heat generated by the lightbulb will reduce the oil/gas/electricity you need to use to heat your house, so there is little net harm done. Any views?

Cardew

Well of course it is true that any heat from any source will reduce your CH bill.

However most of us don't choose to heat our houses with daytime mains electricty which is 3 to 4 times as expensive as, say, gas CH.

roger56

Lightbulbs also have limited life so you'd be replacing them more often.
That will cost and not be paticularly good from an environmental point.

Also Gordon wants his cut (:rotfl: ):
http://www.thisismoney.co.uk/money-savers/article.html?in_article_id=410773&in_page_id=5

(must have been his lightbulb moment)

magyar

rbulph wrote:

I understand that non-fluorescent lightbulbs are not very efficient and that about 80-85% of the energy used by them is converted to heat rather than light. Given that, is it such a bad thing to leave a light on in winter when you don't need it at a time when you would have your heating on? The heat generated by the lightbulb will reduce the oil/gas/electricity you need to use to heat your house, so there is little net harm done. Any views?

Depends how important it is that you have hot ceiling, really.

Cardew

Another thought is that you will also be producing heat during the summer - when you don't need it.

moonrakerz

As already stated most light fittings tend to mounted high up, so you won't actually feel much of the heat as it is being produced above your head and convection will keep it up there. To get much benefit you would need them a couple of feet off the floor - then, of course, they wouldn't be much use as lights !