How to Install Central Air Conditioning in an Old Home

Consult a contractor for an opinion about the best capacity unit for your home and for advice about the best type of air conditioning to install. With an older home, you are likely dealing with older insulation and loose windows, and your home may require a high level of British thermal units, the cooling needs rating for homes. A unit with a high efficiency rating may be the best choice. A contractor can help you determine if installing full or mini-ductwork is necessary.

Install any necessary ductwork throughout the home. A high-velocity, mini-ductwork system may be the choice for an older home because it is less invasive to the old structure. This installation involves snaking the ductwork between floor joists and walls. Run the ductwork through ceiling registers and closets to enter the various rooms of the house.

Set the condenser on a condenser mat in an outside location where it has reasonably easy access to your furnace/air handler. Allow at least 1 foot of clearance from your home.

Install the evaporator coil on your furnace. If you have an air handler, the coil may already be installed inside. Otherwise, you can use the supply plenum of the furnace to mount the coil. It should be facing outward so the refrigerant lines are facing outward. If there is not a place for the coil in the plenum, you may need to construct a shelf for it with sheet metal.

Cut a small hole with a hole saw in the house wall near the condenser. Run the liquid line and suction line between the condenser and evaporator coil through this hole. If you are running them through the house, you can mount the lines on ceiling brackets.

Set up a thermostat and connect it to the evaporator with low-voltage wiring.

Contact a contractor to have the remaining steps completed. The contractor will connect the high-voltage wiring, activate the refrigerant and solder the lines. You should only handle Freon or other refrigerant if you are EPA-certified to do so.