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Currently I have ten 60W incandescent light bulbs heating up my room, very little ventilation, and no ideas on how to stop them from making the room so very hot. If I had other lighting option, I would've switched to them by now, but I have to work with what I have.

How can I prevent the light bulbs from heating up my room, so that I don't lose too much light (at most 20% brightness loss is acceptable), and the lamps don't overheat, or otherwise become a danger?

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10x60 is 600 Watts. That's a lot of lights. Try 40 W bulbs, that will decrease by 33%. 600 W of lighting is a lot! Your still going to have 400 W of lighting by using 40 W bulbs. – Jon Raynor Feb 2 '13 at 5:16
600W is just the right amount for my room with dark wood furniture all around it. – user1306322 Feb 2 '13 at 5:18
It's like asking "how do I prevent this heater from heating up my room?". Incandescent, by design, gives off heat. There's no way around that. – DA01 Feb 2 '13 at 5:24
@DA01 - Totally agree. Either use less wattage or switch to a more efficent bulb. – Jon Raynor Feb 2 '13 at 5:29
up vote 5 down vote accepted

You haven't mentioned what sort of fixture these bulbs are in, but this sounds like a classic case for compact fluorescent lights (CFL).
Efficiency in light bulbs boils down to "for a given amount of power running through the bulb, how much is turned into light and how much is wasted as heat?"
Fluorescent bulbs are much more efficient than incandescents; LEDs are even more efficient, but they're a lot more expensive. Here's a comparison chart from the US Department of Energy.

CFLs are marketed according to the incandescent bulb they could (theoretically) replace; 60-watt replacements draw 13 watts.
As I said, the replacement values are theoretical, and you may find that a 13-watt CFL is not quite bright enough; if so, you could step up to the "100-watt equivalent", which draws 23 watts, and still be generating far less heat than you are now.

The maximum-wattage labels in light fixtures are based on the power drawn and heat generated, NOT on the light produced; you could safely upgrade all the way to these bad boys (55-watt CFL, "250-watt equivalent") without worrying about overheating, but your room would be unbearably bright (and nearly as hot as it is now).

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These 10 incandescent lamps cost me 4 bucks, whereas the equivalent brightness (~2.4) of 100W CFL would cost me about 35. But that's not even the problem, those fluorescent lamps give bad light spectrum (usually). And those CFL which are available to me, are even more expensive and have terrible light spectrums. – user1306322 Feb 2 '13 at 5:13
I agree, switch the bulb, 600 W is a lot, so you have to switch off of incadescent or use less wattage. – Jon Raynor Feb 2 '13 at 5:19
@user1306322 - No. Actually, that sounds like an excellent way to set your room on fire. – MT_Head Feb 2 '13 at 5:25
@user1306322 no, there is no solution. It's a matter of physics. Incandescents give off heat. – DA01 Feb 2 '13 at 5:26
Also look into LED. It's getting more affordable now and would be the best option in terms of least amount of heat as well as a bit more options for color spectrums (plus you will likely never have to replace them). – DA01 Feb 2 '13 at 5:36

A 60-watt incandescent puts out about 800 lumens of light.

A 100-watt incandescent puts out about 1600 lumens.

Your 10 60 watters put out about 8000 lumens total. It'll only take 5 100-watt bulbs to equal that.

60 * 10 = 600 watts heat. 100 * 5 = 500 watts heat.

So, if the sockets can handle it, your room will be a little cooler if you switch to using 5 100-watt bulbs. The room will be just as bright. 150 watt bulbs, if you can find them, will give you still more lumens per watt.

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P = I * A

Typically 10 or 20 AMP circuits draw :

10 * 120 = 1200 W

20 * 120 = 2400 W

Watts of power.

So, 600W is a lot on one circuit, (25% to 50%) of total output.

That in of itself will produce a significant amount of heat.

As @MT_Head says, you need to decrease your draw, and that is only going to be accomplished by switching out the bulbs to a more efficient bulb.

It will be more expensive. but that is the cost of efficiency.

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