How to Keep a Window Air Conditioner from Freezing Up. A common complaint for window air conditioners, aside from not getting the room cool enough, is the complaint of ice forming on the air conditioner. Most people believe this is a symptom of too much refrigerant. It may be, but that's not the only reason why window air conditioners freeze up. Here are a few reasons why window air conditioners form ice.
Check your air conditioner's filter. A dirty filter can cause an air conditioner to freeze up. Clean your filter every couple of weeks. If there are extenuating circumstances like household construction where there's a lot of dust in the air, clean it more frequently.
Clean the cooling coil. This is something you many need a professional to do. If the cooling coil is blocked or dirty, it can cause the air conditioner to freeze up. Clean it every two or three years.
Determine if there is an inadequate amount of refrigerant. Too much or too little refrigerant contributes to air conditioner icing. If you suspect an incorrect amount of refrigerant, contact your service professional.
Make sure you have the right size air conditioner. If you have purchased an air conditioner that is too large for the room, freezing may result. The air conditioner on-off cycle is short because of the room size. The constant short cycle can cause the air conditioner to freeze.
Keep an eye on the outside temperature. If the temperature outside is too low, the air conditioners cooling coil also drops in temperature. As a result, the cooling coil may form ice.