In getting ready for winter, many people want to keep all the bad things out of their AC to insure that it runs well again next spring. However, this is NOT usually a good idea. Here is why:


Ever smelled a dead animal? It’s not good. When temperatures drop and snow starts to pile up, all manner of crawling and furry fauna seek shelter. Covering your air conditioning unit, either with a tarp or a solid cover, will create a tempting home for squirrels and other rodents in the cold weather months.

Before you agree to provide free winter accommodations your neighborhood rodents, you should consider the very real danger that they can pose for an air conditioning unit. Apart from filling the unit with debris such as leaves and twigs to decorate their new home, they will chew the wiring and strip insulation from key components, such a Freon lines to make their nests. Although they will certainly appreciate the protection from wind and snow, you may not appreciate the destruction they will wreak on your HVAC system.

Health Risks  With Mold and Mildew:

trapped mouseWhile animals are an issue for physical destruction such as chewed wiring, disabling your unit, and simply just pest’s, covering your unity will not allow the proper air flow. Trapping Must or Moisture underneath your cover can result in mold and mildew and  actually present a greater health danger.

Securely covering the air conditioning unit will trap air inside the unit and thus lead to a buildup of mold and mildew. Mold and mildew are both types of fungi, with mildew appearing more as a discoloration while mold can develop into larger structures if allowed to grow unchecked. Both represent a significant danger for breathing and their spores can cause serious allergic reactions, bad odors, headaches and life-threatening lung infections.

Removing mold and mildew can very well be a dirty task. Fungi can be difficult to clean but once exposed, homeowners can put not only themselves but family members at risk of serious health issues. Most homeowners will often require the services of an air conditioning service to perform a professional cleaning after uncovering their external unit.

Trapping Moisture Can Cause Damage:

It is pouring rain outside so your first thought is to cover your unit to keep it dry. Even though this seems like a pretty common sense solution, many people don’t understand that covering  their air conditioning unit to prevent further damage does just the opposite in this case.

When covered, moisture from condensation can build up inside, unable to evaporate properly without an airflow. Even smaller amounts of moisture accumulation can lead to secondary problems such as rust, mold and in some cases, even damage related to ice-expansion.

External AC units were made for outdoor use and as such the manufacturers realized that they will receive both rain and snow. So ironically, the best way to protect your unit from moisture is to expose it to rain and snow.

To recap, don’t cover your AC this winter. There are a few minor exceptions, but unless you live in the arctic with lots of falling ice and blizzards, have no worries this winter.