How to Self-Install Central Air Conditioners

Install duct work throughout the home unless it is already installed. You may be able to work with existing duct work from the furnace. A split, ductless system is sometimes necessary in older homes and buildings that cannot have duct work installed.

Set the condenser mat down where you want the condenser to be. The condenser and compressor unit is the outside portion of a central air conditioner. Hot air from inside the building is condensed and released to the outside through this unit. It should be placed about 1 foot from the exterior wall and have plenty of air circulation around it. It can be a loud device, so try to move it away from windows.

Find the plenum of your furnace and place the evaporator coil inside. If you have an air handler, the evaporator coil is already installed. You may need to cut a hole in the plenum with metal shears and construct a shelf made of sheet metal, where the coil can rest.

Cut a hole in the wall near the ground that is large enough for the supply lines to run through.

Connect the suction line to the condenser surface valves. Do not create kinks in this line; use a copper connecting unit if it must be redirected at an angle. Connect the liquid line to the surface valves and run both lines through the hole so they are long enough to connect to the furnace. Do not connect them to the furnace; a contractor must complete that step.

Mount the lines to ceiling brackets or otherwise install them out of immediate sight.

Connect low-voltage wiring between the building's main power circuit and the compressor and evaporator units.

Install a thermostat and connect to the main power supply.

Request a contractor to complete the installation. You should always have your work checked by a professional before running the appliance. A contractor will solder your connecting lines, activate the refrigerant and set up the high-voltage wiring.