One question we hear quite frequently from our customers is whether it is necessary to cover an outdoor HVAC unit over the winter. HVAC units are incredibly durable and designed to easily withstand rain and the elements. In places with fairly mild winters where it rarely, if ever, snows, covering an outdoor HVAC unit typically isn’t necessary. However, in cold, snowy climates like Wisconsin, covering your HVAC unit is usually a good idea. Here is everything you need to know about how to do it correctly and also other ways to prepare your system for winter.

Why Covering Your AC Is a Good Idea

Air conditioners can withstand extremely heavy rains without much issue. As long as it doesn’t rain hard enough to flood the area around the unit, there shouldn’t be much issue since the unit is designed in a way to prevent water from damaging its components. Heavy snowfall is a completely different story, and you generally want to avoid having lots of snow sitting on or inside your AC unit.

If lots of snow and ice sit inside the AC unit all winter long, it has the potential to damage the condenser coils or speed up the rate of corrosion. That being said, the biggest reason that you should cover your AC once you shut the system off in the fall is to prevent lots of leaves, pine needles and other debris from getting inside the unit.

Any organic debris, especially leaves, can collect a huge amount of moisture and create constant wet spots inside the unit. This can lead to corrosion. All of that debris inside the unit will also negatively impact its performance when you turn it back on next spring. If you attempt to run the system when it is clogged with debris, it can also seriously damage the AC unit and potentially cause the compressor motor to overheat and burn out.

You should always have your entire air conditioning system professionally inspected and maintained every year. During this process, the technician will remove any debris from inside the unit and fully clean the coils to ensure your AC works efficiently and effectively. By covering the unit, you should be able to ensure that most debris stays out of it. This way, it should be ready to go in the spring in case you suddenly need your AC before you’ve had time to schedule your annual maintenance service.

One other reason that covering your air conditioner is a good idea is due to icicles. If large icicles form on the gutter above the unit, they have the potential to break off and smash into the AC. The fan blades and cover on top of the unit should prevent icicles from falling inside, but there is always a chance that they could slip through a gap. Should this happen, the icicles can basically act like a spear and damage the coil or put a hole in the refrigerant lines.

How to Properly Cover an AC Unit

While covering your AC isn’t a bad idea, it can actually end up doing far more harm than good if the unit isn’t covered correctly. The biggest issue has to do with condensation and moisture buildup. If you cover your entire unit with a tarp or plastic, it creates a waterproof barrier that will trap moisture inside the unit. All of that moisture trapped inside the unit can lead to major corrosion and cause far more damage than if you left the unit completely uncovered all winter long.

When covering an AC unit, it is essential that you only cover the top part of it to prevent snow, ice and debris from getting inside. Covering it with plastic or a tarp is perfectly fine. However, you don’t want to let the plastic hang down more than 6 inches or so over the side of the unit. This ensures that plenty of air can still flow through the sides of the unit to prevent moisture buildup and the potential for rust and corrosion. There are also specially designed AC covers that are designed to ensure that the unit is protected while still ensuring that moisture can’t build up inside.

The other option is to just lay a piece of plywood over the top of the unit as this will also prevent snow and debris from collecting inside. If you choose to go this route, make sure to weigh the board down well with something heavy. If not, the wind could potentially grab a hold of the plywood and cause it to come slamming down on the AC unit or the refrigerant lines.

Before covering the unit, it is always a good idea to take the cover and fan blade off and then use a vacuum to suck up any leaves and other debris inside the unit. Since you are mostly covering the unit to keep debris out, it obviously makes sense to clean out any existing debris before you put the cover on.

AC Units vs. Heat Pumps

If your home has a central air conditioning unit, covering it isn’t a bad idea as long as you make sure it is done properly. However, if you use a heat pump for both cooling and heating, then this should never be covered. If you were to cover your heat pump and then try to use it for heating, it won’t work properly and will quickly experience serious issues. In most cases, the unit would overheat within a few minutes and then automatically shut down.

Other Steps for Preparing Your AC for Winter

One thing that you should definitely do every fall is inspect the copper refrigerant lines that run from the AC into the house. These lines need to be fully wrapped with insulation or else they could easily freeze and rupture. If any of the insulation is missing or damaged, you will want to have the lines reinsulated to make sure they don’t freeze.

You should also make sure to switch off the power to the AC unit when you turn it off for the last time in the fall. Most air conditioners have a shut-off switch or breaker located on the wall outside within a few feet of the unit. If so, you can simply turn this off. If not, you can also go to your main electrical panel and switch off the circuit breaker that controls the AC.

Shutting off the power to the unit is important as it ensures that it can’t accidentally turn on during the winter. If the unit ever starts up in cold temperatures, it can almost instantly freeze and potentially suffer major damage. For this reason, it is always best to simply turn the power off to it just to be safe.

You should also make sure to check your AC unit after any major snowstorm. A bit of snow surrounding the unit isn’t an issue, but you definitely don’t want huge drifts to build up or have a few feet of snow completely surrounding the AC. Again, all of that snow will allow moisture to collect inside the unit and possibly lead to corrosion. The easiest way to prevent this is to shovel a small path around the outside of the unit after any major snowstorm.

Expert HVAC Services in De Pere

At Healthy Home Heating & Cooling LLC, we are your local HVAC experts and can help with any of your cooling and heating needs. Our certified technicians maintain, repair and install a full range of HVAC units, including air conditioners, heat pumps, furnaces, boilers and ductless mini-split systems. We also specialize in a range of indoor air quality services. For more information or to schedule a service call in De Pere, contact us today.

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