Why You May Not Need To Wrap Your HVAC Unit For Winter

As cooler weather arrives, homeowners often start working through a seasonal checklist to protect their homes from winter damage. That can mean simple steps like adding draft stoppers to doors and sealing windows, but it should also include making sure the HVAC system — short for Heating, Ventilation, and Air Conditioning — is ready for the colder months.

Replacing the filter before turning on the heat is one of the easiest ways to help the system operate smoothly. Once the indoor equipment is taken care of, attention often shifts to the outdoor unit, known as the condenser. Because it sits outside through snow, ice, and freezing temperatures, it may seem sensible to cover it with a tarp during the winter.

However, that is not always necessary. Many major air conditioning manufacturers build their units with materials meant to handle harsh weather, including internal fan blades and the exterior housing and grate, which are usually finished with a protective coating. Even so, those materials are not indestructible. A tarp can trap moisture around the condenser and increase the risk of rust.

A certain kind of cover can still be useful

Although a moisture-trapping tarp can do more harm than good, some HVAC professionals say that not every cover is a bad idea. A properly designed cover can help keep debris out of the unit and may improve the chances that it will run efficiently again when warmer weather returns, as long as it is not being switched on and off repeatedly.

By debris, experts mean leaves, twigs, and pine needles, which are common problems for outdoor HVAC units. These systems usually have open grates on top to allow airflow, making it easy for debris to fall inside. Over time, buildup can block airflow, keep the fan from spinning properly, or lodge in the coils and interfere with heat exchange. In serious cases, the unit can overheat, and dry leaves or pine needles may even create a fire risk.

Keeping that material out of the condenser takes more than simply covering the top. A breathable cover is important so moisture does not collect underneath it. Several companies make mesh covers designed for exactly that purpose, including options sold on Amazon. Even with a mesh cover, it is still important to clear leaves from around the unit and remove any that accumulate on top. Trimming back overhanging branches and bushes can also help protect the system during winter.