consumes more fuel than a heat pump, so you don’t want to keep your system in emergency heat mode longer than you have to. When you manually select EM heat, the heat pump compressor shuts down ...

emergency heat is a setting that controls your home’s backup heating system. It’s a secondary heating mode found on some, but not all, thermostats, particularly those used in heat pump systems.

In the third mode, the heat pump system can maintain the same heating capacity indoors and save compressor power while defrosting, while the fourth mode enables the charging of heat faster by ...