Heating Cooling Electric Plumbing

Heat Pump Basics Every Homeowner Should Know


A heat pump system is an air conditioning unit that provides both comfort cooling during summer and comfort heating during winter. It works like a central air conditioning system, with the only difference being the unit must function throughout the year. Understanding the heat pump basics will help you to purchase the HVAC system that best fits your needs.

How can a heat pump system give off both cooling and heating?

A typical heat pump system has two coils, or heat transfer surfaces, referred to as the evaporator and the condenser. The indoor coil is found inside the air handler or blower compartment. The outdoor coil has a large fan that draws air through it.

To generate the needed mode of system operation, the function of evaporator and condenser is altered. Depending on the mode it is operating in, both coils can work as either the evaporator or condenser.

How does a heat pump system provide cooling?

To provide cooling during the summer months, the indoor coil acts as the evaporator while the outdoor coil acts as the condenser. The inside air travels across the cooling coil (evaporator) and transfers heat from the air to the coil. Once the heat reaches the outer coil, the condenser expels the air to the outdoors.

How does a heat pump provide heating?

The two coils exchange functions in the heating mode. The internal coil works as the condenser while the external coil works as the evaporator. The outside air travels across the external coil, removing the heat from the air to the coil and is transferred to the internal coil. Once it reaches the condenser, the outside heat is expelled to the air traveling across the external coil.

How does the evaporator take in heat?

To take in heat from a substance, the air temperature must be lower than the medium heat being transferred. For example, the evaporator’s surface temperature must be lower than 75° to cool a 75° air in an inhabited space.

To facilitate the preferred heat transfer, the refrigerant (heat transfer medium) is distributed through the coil.

How does the condenser eliminate heat?

It is necessary for the condenser to have a regular temperature that is higher than the surrounding medium. To facilitate the preferred heat transfer, the refrigerant is distributed through the coil.

A refrigerant is a chemical element that can absorb and eliminate huge amounts of heat energy rapidly. Regulating the refrigerant’s pressure at various points in the heat pump system determines whether the heat transfer system works as the evaporator or as the condenser.

How can I keep the evaporator cool?

The evaporator takes in heat into the system, so you need to make sure it is cooler than the refrigerant. To make this possible, it is important for the refrigerant to have a low temperature, too. To obtain the preferred refrigerant pressures in the evaporator, we utilize the compressor and metering device of the system.

How do I keep the condenser warm?

To keep the evaporator cool and the condenser warm, keep the refrigerant’s pressure in the condenser high. The compressor and the metering device in the heat transfer coils obtain the preferred pressures of the refrigerant.

The above are just a few of the heat pump basics you need to know to know how your system works and if you need the help of an HVAC expert.