This time of year we get a lot of questions from air conditioner owners about switching from cooling to heating. The most common question is whether or not to cover the outdoor unit (also called the condenser) of your air conditioning system during winter. If you are considering covering your A/C unit, here are some things to think about.
Covers may do more harm than good.
Air conditioning units are set up to deal with the dry, semi-arid climate of the region where precipitation is relatively scarce; even the snow that falls during the winter months is dry. When it does rain or snow, it’s usually only for a short time. After that, the sun returns and dries up the precipitation fairly quickly.
Putting a cover on your outdoor air conditioning unit prevents this natural drying process from occurring. The liners within the covers have a tendency to absorb the moisture and hold it close to the unit. This can cause the unit to rust because the water is kept in contact with the unit longer than it would be if it was exposed to the sun and wind. This can lead to repairs on your unit sooner than is normally necessary.
Sure, leaving the unit uncovered exposes the paint to the elements, but it also allows the sun and wind to keep the unit dry.
Paint quality has improved.
Outdoor air conditioning units now make use of high-quality, automotive-grade paints that are created to resist weathering and corrosion. In addition, manufacturers design these units to be out in the elements year-round.
Couple that with the weather conditions outlined above – short bursts of precipitation followed by drying exposure to the sun – and there’s really no reason to cover the outdoor unit of your air conditioning system during the winter.
It is damaging to run the unit with the cover still on.
This may seem like common sense, but on that first warm day in spring, it is easy to forget that the unit is covered. Running the outdoor unit with the cover still on deprives the mechanism of its ability to cool itself. Many owners have destroyed or damaged the outdoor units of their air conditioning system after forgetting to remove the cover.
If you do choose to cover your outdoor unit, we recommend turning the breaker that supplies power to the unit to the OFF position. This will prevent you from accidentally running the unit with the cover still on and hopefully remind you to remove the cover in the spring when it’s time to cool your home.
So the short answer to the larger question is no, it is not necessary to cover the outdoor air conditioning unit during the winter months. Some homeowners choose to do so, but we do not recommend winter covers for the reasons outlined above.
There is one situation where we would consider covering the outdoor unit: when it lies directly under or beside a large tree or bush that will be dropping leaves and debris all winter long. In this case, the cover keeps the debris from falling inside the unit where it can cause damage to the internal mechanism. For the most part, the outdoor unit in an air conditioning system is along the side of the home and there’s usually no fol