# Thread: Btu/h output of 100 watt infra red light bulb?

1. ## Btu/h output of 100 watt infra red light bulb?

Is there a difference between the Btu/h output of a regular white 100 watt light bulb vs. a 100 watt infra-red light bulb?

I know it sounds like a silly question but it seems like part of the wattage in the white bulb would be used to produce light in the VISIBLE light spectrum rather than IR.

2. No matter what color, a watt is 3.41 btu

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I think the difference is that a heat lamp is designed to direct the heat where you want it, rather than dissipate it in all directions.

1w is 1w is 1w.

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"Approximately 90&#37; of the power consumed by an incandescent light bulb is emitted as heat, rather than as visible light."

So only 10w of your 100w is converted into light.

"The heated filament emits light that approximates a continuous spectrum. The useful part of the emitted energy is visible light, but most energy is given off as heat in the near-infrared wavelengths."

5. measure the volts an amps to both multipy, compare?

6. Originally Posted by WhoIsThat?
"Approximately 90% of the power consumed by an incandescent light bulb is emitted as heat, rather than as visible light."

So only 10w of your 100w is converted into light.

"The heated filament emits light that approximates a continuous spectrum. The useful part of the emitted energy is visible light, but most energy is given off as heat in the near-infrared wavelengths."
That's the answer I was looking for. It explains it. And it also explains something else I wondered about - how some incandescent bulbs used less wattage (like the G.E. Misers) and produced the same amount of visible light. Apparently they have a little more than 10% visible light output.

7. You need a beer or a woman or both

8. Originally Posted by otto
You need a beer or a woman or both

9. Go wait outside in your skivvies.
They should arrive within the next 45 minutes or so.

10. Originally Posted by otto
Go wait outside in your skivvies.
They should arrive within the next 45 minutes or so.
I tried that, but only the COPS showed up.

And they didn't even bring me a beer.

Did I forget something?

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