Why am I seeing Em Heat on the thermostat?

Em Heat displayed on thermostat

Relax, it’s not broken, there is no emergency. “Em Heat” is a misnomer. You may also see AUX Heat, for auxiliary, also not an emergency, not broken.

So What’s the Story with Em Heat?

The Em Heat kicks on when the temperature drops and it gets cold. A heat pump extracts warm air from outside, warms it, then circulates it throughout your home. When there is no warm air to be extracted from the outdoors, when the temperature is say, 40°F or below, then the emergency heat system kicks on to provide supplemental heat.

That being said, you should be aware and keep on eye on your thermostat, so that you will know if you have a problem on your hands. If outdoor temperatures remain 40°F or below for an extended period of time, expect to see the Em Heat displayed on your thermostat. That’s the heat pump working efficiently, doing its job to keep your house warm. If the temperature dips and it’s cold inside your home and the Em Heat is not kicking on, you probably have a malfunction with your heat pump and you should call in a professional (and, it’s probably cold inside your house.) The opposite is equally a problem: if the outdoor temperature is in the fifties and the Em Heat is still on, that’s an indicator that there may be a problem. Call in a professional.

Em Heat setting on thermostatThe other Em Heat situation to be aware of is the actually setting on your thermostat, Em Heat. That setting actually IS for emergencies. That is, when the heat pump stops working and there is no heat, then, and only then, should you switch it to the Em Heat setting. And also, at that point, you should call in a professional. The Em Heat setting forces the system to use the backup heat, which is costly to run, running up your electric bill, and not an efficient system. It exists to be a backup and to provide supplemental heat when it gets particularly cold. The Em Heat setting is not intended to run round the clock.

A little bit of knowledge goes a long way in keeping your home warm, your electricity bill manageable, and now knowing what ‘Em Heat’ is, your mind at ease.


If you notice any of the trouble signs we noted about heat pumps — or, if your house is just super cold — give Appliance Doctor a call asap!

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