Common joke says that heaters are 100% effient because all they make is heat. How much energy is actually lost?

Question

Common joke says that heaters are 100% effient because all they make is heat. How much energy is actually lost?

In: Physics

Answer 1

There are two things I would want to contribute.

First is that electrical heaters are not exactly 100% efficient, as some of the frequencies of light given off won’t be in the infrared section, so wouldn’t really contribute to any ‘heating’ desired.

Secondly, you could get a more sensible estimate for efficiency when you consider the system you require heating, (e.g. heat loss through walls and windows).