
Traditional glass light bulbs that produce light by heating a metal filament until it glows, emitting a warm spectrum that includes infrared energy.
incandescent bulbs, which we've now stopped using. ... It creates light by running an electrical current through a metal filament until it gets so hot that it glows. Because it relies on raw heat, an incandescent bulb bulb behaves exactly like a miniature fire or a tiny piece of the sun.
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"The speakers discuss the benefits of incandescent bulbs, specifically their emission of infrared light which is compared to energy from the sun, and note that they are becoming harder to find compared to LEDs."