As autumn comes and the leaves fall, we receive many inquiries about protective covers for air conditioners. A/C covers are intended to prevent leaves and snow from accumulating in the cabinet. Are these covers necessary? What are the pros & cons? Should every homeowner use them?
First of all, air conditioners are designed for the outdoors. Some a/c designs collect leaves more than others, but snow and ice will not harm an a/c. The main downside is that some covers retain moisture and can cause the entire cabinet to rust. We have also seen major damage occur when an a/c is accidentally started before the cover has been removed.
Most homeowners do not use a/c covers and their units fail due to old age or lack of maintenance long before rust or leaves would cause any problems. If you must cover your a/c, my advice is to do so only during the fall and only when the air conditioner is located under trees. Use only a breathable cover. Never cover a heat pump. All manufacturers recommend annual maintenance, which returns the unit to its peak efficiency and includes removal of leaves and other debris. This eliminates the need for a cover.
Also note that Trane XL air conditioners and heat pumps are designed with WeatherGuard tops to keep out the leaves and composite basepans and powder coat finishes to resist corrosion.