Why You Should Reconsider Covering Your AC Unit During Winter

There is typically a lot on a homeowner's mind as they prepare for the incoming frost and potential snow of the approaching winter. Worry about possible cracks in lawns and the added weight from feet of snow can be overwhelming. With winter on the way and NOAA predicting colder temperatures in the forecast for the season, one may think it is important to cover their air conditioning unit to avoid frost and snow damage. This assumption, in fact, would be mistaken, as several experts say doing so could result in many issues in the spring.

Besides protecting your unit, covering air conditioning units, particularly for those with ducted systems, is also a common attempt at sealing up your home to prevent cold drafts during the gusty winter months. However, experts from multiple AC companies say this is a massive mistake because it creates an environment for mold growth and a habitat for pests, and could even result in a broken unit. Jason Spurk, Owner of Spurk HVAC, noted this in a 2025 interview with Martha Stewart, saying, "Covering your AC unit for winter can lead to restricted airflow — especially if it is covered too tightly."

One of the main dangers of draping a tarp over your air conditioning unit is that it traps any moisture from melting snow and ice underneath the cover. In states that experience long periods of freeze-thaw cycles, this creates a perfect environment for dangerous mold growth. While you can easily get rid of mold that grows in your garden using household products, mold that grows on the metal of your AC unit can be highly dangerous, as the spores can spread through your home quickly. 

This moisture also creates a breeding ground for rust, which can wear away at your unit and cause irreparable damage. Another issue that you might experience is due to the insulated environment created when you cover your unit. In cold regions, all kinds of critters looking to survive the winter, including mice and rabbits, find their way under the warmth of the tarps and can create quite the scene in the spring.

Ultimately, covering your AC unit is unnecessary as most units are designed to shed both water and ice and withstand the elements, not fester under warm, wet covers. Instead, owners should protect their unit from winter weather using simple practices, like often clearing snow.