It shouldn't be surprising at all MrAl, the luminous efficiency of typical incandescent bulbs is only between 2 and 5%. So best case scenario 95% of the energy going in is turned directly into heat. Figure a couple 100 watt bulbs per room, more in larger houses and you're talking a pretty significant source of heat. CFLs I think are in the neighboorhood of 20% efficient, this is still abysmally low but it's 4 times better than an incandescent so the amount of heat they put out is significantly lower. The homes heating system has to make up for this difference.
We have a few warm white CFL's the high frequency switching makes them flicker free and the light quality is difficult to tell apart from our regular incandescent bulbs. We'd be using all CFL's right now but the 3 way CFLs are physically too large the stick up out of the top of our floor lamps and you can directly see the bulb which is horrid.
The energy efficiency is hard to beat, but people seem to forget they contain mercury and if EVERYONE used CFLs that would likley become a pretty serious problem, because VERY few people are going to remember to properly recycle their bulbs.
Hi there,
It is surprising to me because i used to have to use a 1300 watt electric
heater to add supplemental heat to a medium sized living room. That was
in ADDITION to the regular heating which would not bring the temperature
up enough on cold days, and even that wasnt enough to make much of
a difference. Yes, incand's are very inefficient light sources and make
better heaters than light bulbs (ha ha ) but still 200 watts just doesnt
do very much. It's the plain wattage i am talking about here, not the
bulb itself. 200 watts worth of light bulbs probably wouldnt even glow
in that living room (he he).
Now if it was a very small enclosed area i might believe it, such as
under the covers in our beds. If we were able to take 200 watts worth
of bulbs under the covers with us, that would be more than enough
and probably 100 watts would do it even on very cold nights.
Think about this...some CPU's use almost 150 watts...that's a lot
but not much when it comes to heating a room in a house.
Along that same line of thought, the surface area of a heat sink is
not very much in comparison to the surface area of the walls, ceiling,
and floor of a room in a house, and the temperature rise has a lot to
do with the surface area of the heat sink, rising less for more surface
area. Think about how good a heatsink for a CPU would be if it could
have the surface area of even a small room...temperature rise 0.1 deg C
maybe?