Can heat from a 60 watt light bulb actually significantly heat up a room?

Question

My husband and I have been arguing about this. He keeps turning off the light in the room I am in, saying that the lightbulb is making the room hot. I know they emit heat, but enough degrees to actually feel a difference? It is a 60watt bulb in a 250 sq foot room.

Answer 1

Yes. Only a fraction of the electricity that goes into an incandescent light bulb produces light; the rest is heat. Change all your incandescents to compact fluorescents, and you will reduce the heat output as well as saving electricity. The standard 13-watt CF produces almost the same light as a 60-watt IB, and very little heat.

Answer 2

The efficiency of a bulb is around 20%. So 80% comes off as heat. Your 60W bulb is like a 48W heater.

From one ad on small heater:

"The Presto Parabolic Heat Dish is a cost effective choice for workshops or garages when you want to heat just you and not the entire building.

The Cozy Legs radiant heat panel, with only 100 watts of heat output is by no means a whole room heater, but performs admirably when installed under a desk or hung on the wall to warm a bird cage."

From here we can see that the 60W bulb is about 1/2 the power of this "personal" heater. So yes if you are near the bulb, and not as much if you have a big room.

You may wish to change the bulb to a fluorescent light which is 5X more efficient and you would not have this problem of heat. Additionally, your energy savings ($$$) will be significant over time and you are also helping the environment.

Answer 3

a compact fluorescent bulb is the way to go, as the previous answerer stated. These are the coil shaped bulbs that you can find at any department, discount or hardware store. They do make these bulbs shaped like traditional light bulbs as well. The are much lower wattage (and lower heat) than traditional bulbs, and last many times longer. The drawback is price, they aren't cheap at all (Lowe's sells some 13 watt bulbs, which i believe are the equivalent of a 60W regular bulb, in 3 packs for around 8 bucks) You could even go with 23 w bulbs, which equal 100w in terms of brightness. It is best to buy these suckers at lowe's or home depot, because most other places seem to overcharge for them. I have them in every fixture in my house, and have noticed a slight dip in my electric bill. Happy bulb hunting!

Answer 4

Yes it can.

There is a modern way used in Germany to build ultra-efficient homes. This technology allows to isolate a house so efficiently that it actually doesn't have any heating system (besides the one for heating water). In order to keep such a house in an optimal temperature, light bulbs are used to heat the house. I know it sounds unbelievable but it is actually true.

The question is of course how big is the room, how well isolated it is and what is meant with "significantly heat up". These are all very variable issues.

Hope this helps

Answer 5

Looking up the numbers the Heat Capacity of air is approximately 1 kJ/(m^3 K)

Assuming an 8 foot high ceiling then your room is about 70 m^3 ( a big room) so the Heat Capacity of the room is 70 kJ/K since a 60 watt bulb puts out 60 Joules/sec the room temperature will rise 3 C / hour assuming no losses. 3C is about 5F/hour

Answer 6

Depends on a lot of things related to how well insulated that particular room is.

Also interesting to note is that the human body emits the same amount of heat to the surrounding environment as a 100 watt bulb.

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Answer 7

Practically speaking, no. If you check the wattage on electric heating units, they are anywhere from 20 to 50 times more wattage.

HOWEVER, you do pay for the wattage you expend whether you are in the room or not. If you want to keep the light on, substitute one of the 16 watt fluorescent lights they now sell.

Answer 8

It will heat up the room, but only by a very small amount. I wouldn't say it would be easy to notice. Hope this helps.

Answer 9

Some pretty good arguments.

Answer 10

I agree with titobob i have done that it does work.