What is the primary function of the heat exchanger in a heat pump?

The primary function of the heat exchanger in a heat pump is to facilitate heat transfer between indoor and outdoor air. In a heat pump system, the heat exchanger plays a critical role in moving thermal energy. During the heating cycle, the heat exchanger allows the refrigerant to absorb heat from the outdoor air, even in cold conditions, and transfers that heat indoors. Conversely, during the cooling cycle, it extracts heat from the indoor air and releases it outside. This ability to transfer heat efficiently is what makes heat pumps effective for heating and cooling spaces, highlighting their role in energy efficiency and climate control.

The other options pertain to functions or components that are supportive but not central to the primary purpose of the heat exchanger. Filtering indoor air relates to air quality and is not the job of the heat exchanger. Compressing refrigerant is the role of the compressor, another part of the heat pump system. Lastly, controlling thermostat settings pertains to system regulation but is unrelated to the specific role of the heat exchanger in heat transfer.