eli5: If most electronic appliances’ efficiency losses are through heat, does that mean that electric heaters are 100% efficient?

Question

Edit:

Many thanks for your input everyone!

Just to clarify, I don’t want to take into account the method of generating electricity or shipping it to the home, or the relative costs of gas and electricity. I just want to look at the heater itself! i.e. does 1500W of input into a heater produce 1500W of heat, for example? Or are there other losses I haven’t thought of. Heat pumps are off-topic.

In: 1063

Answer 1

When talking about the efficiency of anything you have to be a little more specific. For example electric heaters are 100% efficient at turning electricity into heat. 1500w of electricity will give you 1500w of heat. However heat pumps can turn 1500w of electricity into almost 4500w of heat by moving it from outdoors to indoors. But this depends on the temperature differential between the two. At a high enough temp difference (example: -15 outdoor/68indoor) your heat pump can actually use more watts of electricity than it can move in heat. And you need back up electric heating.

So when you talk about efficiency you have to specify at doing what. If you have two 1500w electric heaters and 1 with a fan, both will turn 1500w of electricity into 1500w of heat. But the one with a fan would more efficiently heat a room because of the more even temp you would have throughout the room.