How to Replace an A/C Unit With a Heat Pump

Shut down the A/C unit from the thermostat and turn off the power at the circuit breaker box. Follow the manufacturer's instructions in removing the wiring connected to the thermostat for the A/C unit. If you are not confident to do this yourself, ask a certified electrician to perform the wiring work.

Loosen the refrigerant lines from the outside A/C unit. Attach the pipe wrench to the line connections and turn it counterclockwise. Remove the A/C unit from the concrete base. Place the heat pump unit onto the base.

Attach the refrigerant lines to the heat pump if the type of heat pump you are using is compatible to the lines. Alternatively, remove the old refrigerant lines from air handler attached to your furnace unit if the heat pump is incompatible. Install new refrigerant lines by securing the connections from the outdoor unit to the indoor unit when using the same duct lines as the furnace.

Replace ducts to a larger size to handle the increased amount of airflow provided by the heat pump. For example, install 8-inch round lines for the rooms if the current ducts are 6-inch. Install 16-inch square pipe for the plenum system (main pipe run) to replace 12-inch or 14-inch pipe.

Unwrap the aluminum tape from around the duct seams. Remove the sheet metal screws with a No. 2 Phillips screwdriver. Install the new duct by screwing in 1/4-inch sheet metal screws, using the screwdriver.