It depends on the framing of the question a bit. If we are defining 100% efficiency as 100% of electrical energy being converted into kinetic energy (heat) by the device, then that is a no. Some percentage is emitted as EM radiation instead of heat. If they were so then a light bulb or a bomb is a 100% effective heater as well.
CookieOfFortune@lemmy.world 2 months ago
It depends on what you consider the room: Both a light bulb and a bomb would deliver all their energy around a fully enclosed room. Incandescent bulbs are indeed effective heaters, LEDs just deliver much less energy. And a bomb, by design, is hard to contain in a room.