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With its filament held within a vacuum, does the temperature of ambient air surrounding the bulb affect the power consumption of an incandescent light bulb.

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Since the temperature of the filament in an incandescent light bulb is so much higher than any reasonable ambient temperature, its power consumption would not be affected to any significant degree.

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Yes. The filament is thermally joined to metal supports that then connect to the metal connections outside the bulb. So, the temperature of the filament is affected by the ambient temperature of the surroundings. The resistance of the filament is highly temperature dependent, so changing its temperature changes its resistance, which changes its power consumption.

This effect will be so small that it would be extremely difficult to measure.

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    \$\begingroup\$ Heat transfer via the inert gas fill is MUCH more significant than any transfer via the filament supports. \$\endgroup\$
    – Dave Tweed
    Commented May 14, 2021 at 13:52
  • \$\begingroup\$ Thermal radiation may have a slight effect also. \$\endgroup\$
    – Mattman944
    Commented May 14, 2021 at 14:02
  • \$\begingroup\$ @DaveTweed Yes, I agree. I guess I was being sarcastic with the answer, since almost any question that includes "have any affect on" will almost certainly get an answer of "yes", just like almost any question that asks "is it possible". The OP stated that the filament was in a vacuum, which as you point out is not true. \$\endgroup\$ Commented May 14, 2021 at 15:15
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Assuming supply voltage is fixed, the power consumption is only affected by the resistance. The resistance of the tungsten filament is somewhat dependent on the temperature (with a positive tempco), so a higher filament temperature will result in lower power consumption.

All heat loss to the environment is dependent on the temperature - conduction through the filament supports, convection and conduction if the envelope is filled with a gas (consumer large lamps typically are, smaller lamps often not), and radiation.

So if the ambient temperature (including all objects that influence the lamp) increases in temperature you can assume the power consumption will be decreased a bit, the lamp will emit more light (thus becoming more efficient), however the lamp life will be shortened. Also, the light will look "colder" (higher colour temperature).

As to the amount to expect, the temperature of the bulb is at several thousand degrees C (or K), so normal room temperature variations have little effect. However, under more extreme conditions there may well be a noticeable effect. Quoting Haier/General Electric Appliances:

A bulb that isn't rated for oven use will not last long in an oven! We recommend using only genuine GE Appliances parts.

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    \$\begingroup\$ First person who said that higher ambient temperature will cause slightly lower power. \$\endgroup\$
    – Mattman944
    Commented May 14, 2021 at 23:07

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