Can you use an extension cord with a window air conditioner unit?

Answer 1

Yes, but be sure it is of sufficient rating to handle the current. Air conditioners typically use a large amount of electrical current, and so the ampere rating of the cord needs to be high enough not to cause appreciable heating or failure of the cord. Also, the longer the extension cord, the heavier its gauge needs to be, as its resistance goes up in direct relationship to its length. If the resistance of the extension cord gets too high, the compressor motor will see insufficient voltage to start up reliably and will run poorly or not at all. Look for an "appliance extension cord" when you go to the store. They are easily distinguishable from ordinary lamp extension cords by their heavier weight cable and they're almost always equipped with a 3-prong plug and receptacle. Keep the extension cord run from the outlet to the air conditioner as short as practical -- less than 12 ft (4 meters), if you can.