How to Convert Central AC to Heat Pump

A heat pump is a heating system that uses compression and expansion to transfer thermal energy from a cold environment to a warmer environment.

Heat pumps and air conditioners both use compression and expansion of a refrigerant to move around thermal energy.Heat pumps and air conditioners both use compression and expansion of a refrigerant to move around thermal energy.
It works with the same system as an air conditioner, except backwards. You can convert a central air conditioner unit to a heat pump -- without any cooling capabilities -- by basically switching the direction the refrigerant flows through the system. You should avoid trying to convert an AC unit into a heat pump/AC unit that heats and cools, since the complexity of the piping and controls is normally considerably more than just purchasing a new unit.

Remove all of the refrigerant from the system and store it in the refrigerant container. There typically is a filling port near the compressor unit where you can drain the refrigerant out of the system into a refrigerant container.

Disconnect the tubing running to the outside heat exchanger and the compressor. You are going to need to switch half of the pipes, so it is generally easier to disconnect everything then reconnect it in the correct order. Also remove the expansion port which is located at the output of the outside heat exchanger.

Screw the output of the expansion port onto the outside heat exchanger's input then connect the tube running to the output of the interior heat exchanger to the input of the expansion port.

Use the piece of tube running between the outside heat exchanger and the compressor to connect the output of the heat exchanger to the input of the compressor.

Connect the output of the compressor to the tube running to the input of the heat exchanger inside.

Switch the thermostats on the heat exchangers. There should also be a frost sensor on the cold heat exchanger that could be integrated into the thermostat.

Refill the system with refrigerant from the container.

Things You Will Need

  • Empty refrigerant container
  • Open-end wrenches