How do heat pump split systems work?

A split system heat pump works by transferring heat, and acting as both a heater and cooler. Using an indoor unit with an evaporator coil and an outdoor unit with a condenser coil connected by refrigerant lines.

In heating mode, the evaporator coil absorbs heat from the outside air, even in cold temperatures. The regerant, which is a liquid, absorbs this heat and evaporates into a gas. The fan inside the indoor unit blows air across the evaporator coil, warming air as it circulates through the room.

In cooling mode, the evaporator coil absorbs heat from the inside air, cooling it. The refrigerant absorbs heat from the inside air, evaporating and cooling the air. The fan inside the indoor unit blows the cooled air into the room.

A reversing valve switches the direction of the refrigerant flow, allowing the heat pump to switch between heating and cooling modes. Split system heat pumps are typically ductless, meaning they don't require a central duct system, allowing for more flexibility in installation and zoning.