How to Make an Old Window Air Conditioner Work Better

Press the “Power” or “On/Off” button on the control panel to turn the air conditioner off. Pull the plug from its power outlet.

Pull open the front grill with your fingers and locate the air filter within the unit. Grasp the top of the air filter and pull it out of its slot. Turn on warm water from a faucet and hold the filter underneath. Run warm water over both sides of the filter, until all old dirt and dust vanishes. Allow the filter to air dry or blot it with a towel, until it’s completely dry. If a filter is damaged, replace it.

Either unscrew or pop off the front cover of the air conditioner unit, being careful not to break it. Pull on the edge of the pan at the bottom of the unit. If the unit slides out, remove it. If the unit doesn’t slide out, it’s screwed to the cabinet. Insert a screwdriver into the unit’s cabinet screws and unscrew them. Remove the unit and take it outside.

Unscrew the screws to the inside and outside coil panels. Wedge the unit up on one side so that the electrical components are elevated and the inside coil is lower than the outside coil. This prevents water from washing over the electronics of the air conditioner.

Spray the inside coil and fan blades with coil cleaner and allow it to sit for five minutes. Spray the coils and fan clean of the coil cleaner with the hose, being careful not to soak the air conditioner electronics. Repeat, until all of the old dirt is gone.

Allow the unit to dry and screw the inside and outside coil panels back onto the body. Carry the unit back inside and reinsert it into the cabinet. Replace the cabinet screws. Insert the filter back into the air conditioner and replace the front cover. Plug the old air conditioner in and press the “Power” or “On/Off” button to test it.