How Heat Pumps Can Generate Both Warm and Cool Air

Heat pumps can operate as both heaters and air conditioners, and they are not units that put two separate systems in the same cabinet: a heat pump uses the same mechanism to provide both warm and cool air.

We often get questions from customers about how a heat pump works. There are many technical details involved in a heat pump’s operation, but we can provide you with a simple breakdown that focuses on refrigerant (how the air conditioner mode works) and the reversing valve (how the heat pump can switch from AC to heating). For more information and to schedule installation for cooling and heating in Spring, TX, contact KAC Express.


Running through the heat pump in a closed loop is a chemical blend called refrigerant that can easily change from liquid to gas and back again. Starting in the indoor coil of the pump, the refrigerant absorbs heat from indoors through the process of evaporation. This results in the indoor air feeling cooler. The refrigerant then moves to the outdoor coil, where through the process of condensation it releases the heat to the outdoors. This cycle—known as heat exchange—then starts over.

The Reversing Valve

So far, so good: we have air conditioning power from a heat pump thanks to the refrigerant. Now…how do we change a heat pump into a heater?

This is where a key component in the pump—one that differentiates it from a standard air conditioner—enters. The reversing valve sits on the refrigerant line, and when it receives an electrical charge, it switches the direction in which the refrigerant moves. (In our example, charging the valve causes a switch to heating mode. This isn’t the same for all reversing valves; it depends on the heat pump manufacturer.) Now, the two coils of the heat pump swap functions. Refrigerant moves to the outdoor coil, which now acts as the evaporator coil that absorbs heat. The heated refrigerant now moves to the indoor coil, which acts as the condensing coil that releases the heat to the indoors. Voila, warm air.

Heat Pumps May Be Ideal For Your Home

In Texas weather, heat pumps work exceptionally well: they usually never have difficulty extracting sufficient heat from the outdoors during cold weather, and their AC mode is as effective as any standard AC of the same size. Heat pumps take care of two comfort needs in one unit, saving space and money. (They are especially efficient at energy use in heating mode compared to a furnace.)

To find out if a heat pump will do the best job for your home, contact KAC Express and talk to our HVAC specialists in Spring, TX, today about your heating installation options today.