All heat pumps operating in northern climates (below 35°F) normally need a supplemental heating source. Usually this is in the form of electric heating provided by the indoor unit. Other sources could be gas, oil, or hot-water back-up systems as well. The supplemental heat is also referred to as "second-stage" or "back-up" heating, with "first-stage" being the heat pump only. Emergency heat is when you use your supplemental heat (2nd stage) by itself, without the use of your heat pump (1st stage heat). The Emergency heat option is not available for non-heat pump systems.
If this feature is available to you, you can find it and turn it on by going to Modes > Emergency heat.
For more information or a visual representation of steps please reference our user guide here
