The package system is self-contained. When it's hot outside, the electric heat pump functions as a central air conditioner. The coil inside your home is the evaporator coil. The air circulating in your home is cooled and dehumidified. Heat is extracted from the home's air by the indoor coil.
Refrigerant liquid carries heat to the outdoor unit.
Heat is transferred outdoors. The heating cycle is the exact reversal of the cooling cycle. The electric heat pump can extract heat from the outside air even in extremely cold temperatures. It may be hard to believe, but air at 0 degrees contains almost 90 percent of the heat it contains at 70 degrees. But when the outside temperature is very low, there may not be sufficient heat in the supply air to keep your home warm.