Emergency Heat on the thermostat
The Emergency Heat switch on a heat pump confuses a lot of people. What is it? When do I use it? Do I turn it on when it’s really cold? These are all great questions! Heat pumps need a supplemental heating source. Especially when the outdoor temperature dips below 40 degrees. These supplemental heating sources are things such as electric resistance heating at the indoor unit, gas oil or even hot water back-up systems. Supplemental heating sources are known as “second stage” or “back up” heating. Your heat pump only is the “first stage” heating. Emergency heat is when you use your “second stage” heat by itself without using your “first stage” heat.
So, when should you use Emergency Heat? Exactly as the name implies – in emergency situations only! It’s used when your “first stage” heat does not heat your home. When your outdoor unit is not functioning, turn to “Emergency Heat” and call for service. The Emergency Heat will only turn on the indoor unit and back-up heat. Having Emergency Heat on will be more expensive to run and will increase your utility bill greatly. This is why it is only used in an emergency situation.
If your Emergency Heat light is on but your thermostat is NOT set to Emergency Heat, this is an indicator that there is a problem with your heat pump and you should call for service.
Auxiliary Heat will turn on automatically when your heat pump can no longer transfer heat from the outside. This usually happens when the outdoor temperature goes below 40 degrees. The thermostat will sense this and turn on the electric heat strips automatically and provide the additional heat as needed.
It does need to be noted if your thermostat stays in Auxiliary Heat after the outdoor temperature rises above 40 degrees, you need to call and have it serviced. A heating system stuck in Auxiliary Heat will run up an energy bill quickly.