Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: heat output of light bulb

Learn more physics!

Most recent answer: 06/20/2015
Q:
Is there a way to calculate the heat output of a light bulb? My device originally used a 12 volt 2.2 watt bulb, but those are getting expensive. I can find a 2.7 watt bulb for less, or a 3 watt bulb for less yet. But, I don't want to melt anything. (We have another application that calls for a 23 watt bulb, and if you put a 32 watt bulb in it, the housing melts.)
- Paul Curtis (age 43)
Omaha, NE USA
A:

The heat output is essentially the same thing as the wattage rating. A little of the input energy will escape as light, but most of it is dumped as heat into the bulb and its immediate surroundings. If these are incandescent bulbs you could replace them with LEDs (available for 12V circuits) that give the same light output with less than 1/4 the power input, and thus less than 1/4 the leat output. They cost more but last much longer.

Mike W.


(published on 06/20/2015)

Follow-up on this answer.