During the winter months, it's important to winterize outdoor appliances used regularly during the summer months, including air conditioning units. Window air conditioning units should be removed for the winter. However, the question regarding whether your standalone central air conditioning system needs covering remains debated.
The United States Department of Energy suggests that covering the outdoor unit of your central air conditioning system during the winter months to protect the unit from debris, snow and ice. You may say to yourself, "Well it can't hurt if it's covered."
According to several home improvement sources, covering the unit may prove counter productive in some cases. If the cover is applied incorrectly, moisture can get caught inside and lead to rusty components. This has the potential to also provide small animals with a nesting spot during cold weather months. In addition to these factors, most manufacturers don't suggest doing covering the unit.
For people who cover the unit, they claim benefits such as keeping the coils cleaner that lead to a more efficient, cleaner and longer-lasting unit. Debris will not get caught inside the fins or deep within the unit. Lastly, it prevents freezing water from damaging the coils. When the weather starts to change during the early fall months, most people decide they don't need the air conditioner anymore. The earlier you cover the unit in the fall season, the better protection it will receive. To prevent leaves from getting caught inside the coils and fins of your air conditioner, cover the unit before the leaves start falling to the ground.
It's believed that the unit is built sturdy enough and should stand up to all types of weather including extreme snowfall amounts. Therefore, many air conditioning models do not mention covering of the unit as a maintenance requirement during winter months.