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Q & A: Light bulb giving off heat

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Most recent answer: 05/16/2013
Q:
Does a light bulb give off heat?
- Michael
austin,texas,U.S.A
A:
Sure. If you put your hand near a bulb, you can feel that itís hot. If you happen to have an infrared absorbing filter, youíll notice that it also gets hot, so some of the energy is coming out as infrared light. Since the bulb gets hot, it directly heats the air around too.

Mike W.

(published on 10/22/2007)

Follow-Up #1: light and heat

Q:
is a halogen flood light safe in any light socket or lamp????? thanks.AND HOW MUCH HEAT WILL IT GIVE OFF OR DOES IT PUT OUT A LOT OF LIGHT. THERE IS THIS GUY ON THE NET MAKING HEATERS FROM THESE LIGHTS HAVE U SEEN THESE PICS/
- doris
HARMONY N.C.
A:
We really can't say whether the halogen flood light would be safe or not in some lamp. That depends on how easily it can cool off, and we just don't know enough to answer even if the lawyers would let us.

I can answer another side of your question, however. Nearly all of the bulb's rated power turns into heat. Only a small fraction is converted to light. That's true of halogen bulbs even though they are more efficient than standard incandescent bulbs. I think it's true of fluorescent bulbs even though they are about 4 times as efficient as standard bulbs.

Mike W.

(published on 05/16/2013)

Follow-up on this answer.