Adding Freon to a window air conditioner involves cleaning the air conditioner, attaching a new Freon container and allowing it to intake new Freon until the container is drained. While this task is usually performed by a refrigeration mechanic, a lay person can complete it by purchasing a Freon kit.
Gloves and protective eye wear should be worn when adding Freon to an air conditioner. Refer to the air conditioning unit's user’s manual to ensure that the right type of coolant is used.
After taking the air conditioner out of the window, lay it on a level surface near running water. Clear any dust or dirt from the coils, the louvers or shutters and the air filter. Give these parts time to dry before putting the unit back in place. Do not switch on the power.
Upon finding the air conditioner's compressor, remove both valves from the Freon kit. Follow the kit's instructions as to how to attach these valves to the lines of the compressor, and take out the Freon container. Attach it to the valves, turn the unit on, and set the power to the highest level. This setting allows the air conditioner to draw the Freon into its coils. Observe the unit for cooling temperatures. Once all of the Freon is drained from the container, turn the air conditioner off, unplug it, and remove the Freon container. After closing off the compressor's main lines, it is safe to resume use of the unit.