Where is the indoor coil typically mounted in relation to the auxiliary electric heat strips?

In a heat pump system that utilizes auxiliary electric heat strips, the configuration typically involves the indoor coil being mounted before the heat strips. This arrangement is pivotal for ensuring that the air passes over the indoor coil first to absorb heat before it reaches the electric heat strips.

The primary function of the indoor coil is to facilitate heat exchange by absorbing heat from the refrigerant circulating within it. When the heat pump operates in heating mode, the indoor coil Extracts heat from the refrigerant and transfers this heat to the air that is blown across it.

In situations where the heat pump cannot meet the heating demand — often due to extremely low outdoor temperatures — electric heat strips are used to provide supplemental heating. By positioning the indoor coil before the heat strips, the system can optimize heat extraction first from the refrigerant, and only utilize the electric assistance when necessary, improving overall efficiency.

This sequence maximizes energy utilization and helps in maintaining the desired indoor temperature effectively. Therefore, this setup emphasizes the indoor coil's role in enhancing the primary heating function of the heat pump before resorting to supplemental heating methods like the electric strips.