Air conditioner next to leaves

Updated: 09/17/2020


In the world of air conditioners, the argument of covering your unit never ends. One side argues that AC units are built to be outside and don't need any extra protection and claim that covering your unit is more harmful than helpful.

The others tend to take a "better safe than sorry" approach to AC protection and focus on maintaining air conditioner efficiency. With the weather more unpredictable than ever, you should know both sides of the argument to make an informed decision.


Should I Cover My Air Conditioner?

If you live in an area that tends to have extreme weather, such as blizzards and hailstorms, covering your outdoor air conditioner will help prolong its life and save you from making expensive repairs. Air Conditioner Covers aren't necessary for mild climates, but are still useful to keep out stray leaves, dirt, rocks, grass, and other debris.


The key reason to cover your air conditioner is to keep it efficient. An efficient AC unit means your electric bill is lower, and you save money on maintenance and eventual replacement. With outdoor AC replacement costing anywhere from $1,000 to $6,000, having a cover for when inclement weather hits can be a life (or rather, air conditioner) saver.


What Dangers Does My Air Conditioner Face?

Snow and Rain

Cold winter weather causes the most damage to air conditioning units. Snow piling up on top of the unit isn't the problem — the melting is.


If temperatures rise above freezing, the snow will melt into the interior of your air conditioner. Depending on how old your air conditioner is and what metals it's made of, water could cause rust and corrosion. On top of that, the water could refreeze around the condenser coils, slowly weakening them.


Freezing rain and snow will also cause ice to form on the air conditioner fins, pushing the fans out of place. When you turn your AC back on in spring, air won't be flowing the way it should, and you may notice your home isn't cooling as well as it used to.

Outdoor Air Conditioner Covered With Snow

Dirt, Leaves, and Other Debris

Due to needing airflow when running, air conditioners are not designed to keep out leaves, seeds, rocks, and grass. A small amount of debris won't cause much damage. But problems arise when leaves and debris start to build up.


Wet leaves and grass piled in the bottom of your air conditioner will start to decay, which produces formic acid. A build-up of this acid on the copper tubing can eventually cause corrosion. In turn, this leads to tiny holes in the tubing for refrigerant to escape.


Freon leaks are dangerous not just to your AC unit, but to the environment and people. Refrigerant releases harmful chemicals that cause ozone layer depletion and soil damage. People exposed to Freon will experience skin dryness and irritation. Prolonged exposure can even lead to respiratory damage, including chronic bronchitis and pulmonary disease.


While a more minor concern, if your air conditioner has low refrigerant, the compressor will overwork, damaging other parts of the HVAC system.

AC cover protecting an air conditioner from snow
Full air conditioner covers prevent anything from getting inside your AC unit.

Dirt and dust getting into your AC unit can lead to dirty air ducts, condenser coils, and fans. Dirty air ducts can make allergies and asthma worsen. Your indoor air quality decreases if you have air ducts coated with dirt and grime.


Dirt acts as a sponge. If water gets into the air ducts, it won't evaporate or pass through correctly. This can lead to mold and mildew development, causing musty odors.


Dirty air ducts, condenser coils, and fans will decrease your AC unit's efficiency by causing increased wear on the interior parts and restricting airflow. Areas with high air pollution are more at risk for dirt and grime build-up, making an outdoor air conditioner cover beneficial year-round.


You may overlook the consequences of dirty condenser coils in the winter. But as summer rolls around, your air conditioner will need more energy than usual to cool your home. Your system will have to run for longer periods of time, causing it to wear down sooner than expected.


Another danger is large rocks, seeds, and nuts falling into your unit. This can cause dents on the exterior metal slats and interior fans, disrupting airflow. Rocks and large nuts (like walnuts or acorns) may not affect your air conditioner right away if your unit isn't on. But when it kicks on again, the fan will pick them up and start banging them against the walls. This can end up denting the fan, and is also noisy and disruptive. The noise alone might make you call a maintenance specialist, just to have them tell you a squirrel threw a couple walnuts inside (and then charge you $200 for the visit).


Hail and Icicles

Air conditioning units are often forgotten during hailstorms, with most of the focus on your car and roof. They are just as vulnerable to interior and exterior damage, especially if located on top of a building.


Most dents on the outside of your air conditioner won't affect how it runs. But falling icicles and hail can dent the metal slats, impeding airflow.


If hail makes its way inside, it can damage the fans, affecting the unit's airflow. The fans can get wobbly, cracked, or bent by large pieces of hail. A wobbly fan will still work but will cause interior damage over time. Since the fans create airflow to pull heat from your home, a damaged fan will end up removing less heat. Your AC unit will be working harder and longer with less impact. Severely damaged fans may even cause the unit to shut down (not something you want to happen when it's 100 degrees out).


Falling icicles and hail can also damage condenser coil tubing, thermostat wiring, refrigerant tubing, and ductwork.

Armor top air conditioner cover protecting an AC unit
Armor top AC covers protect against hard objects like hail, icicles, and rocks.

Do I Need to Cover My Air Conditioner in the Summer?

Most people only cover their air conditioners in the fall and winter but using a cover in spring and summer months can be beneficial.


Use a Top-Only Mesh Cover for an extra layer of protection from debris falling from your gutters or trees, such as acorns, twigs, and leaves. A mesh cover allows for proper airflow so it can be left on while the unit is running. Mesh covers also protect from the sun. This is beneficial for two reasons — your air conditioner will remain looking like new and it will keep the unit cooler, making its job of cooling your house easier.


If you face spring and summer hailstorms, an Armor Top Cover may work best. These covers have four armor plates sewn into the top to protect from ice. Keep one of these on hand to use when hail is in the forecast. Armor top covers provide better UV ray protection than mesh top covers; however, they cannot be left on while the unit is running.


Top air conditioner covers won't provide as much protection, but that typically isn't a problem during spring and summer. When fall and winter roll around, opt for a weatherproof Full Air Conditioner Cover to avoid the damages mentioned previously. Full AC covers aren't recommended for the summer unless you expect a severe storm or rarely turn on the AC. These covers also protect from damaging UV rays. If you keep your outdoor air conditioner cover on during the spring, it will stay cooler than it if sat in direct sunlight all day. This means your home will cool down quicker (and run more efficiently) once you take your cover off and flip on the AC for the summer.


Do I Need to Cover My Window Air Conditioner?

Window and wall air conditioners are an affordable way to cool down your home or apartment during warm springs and summers. They are not only affordable, but also more energy efficient than central air conditioner systems.


As the weather starts cooling down in fall and winter, cold drafts will sneak through your indoor AC unit. It goes both ways – heat will also escape from your house. This makes your heater work harder to keep your home warm, resulting in a higher electric bill.


Dust will also build up in your wall unit when it's not in use. When you go to turn it back on in spring, you'll be stuck cleaning the vents before you can use it.


Using an Indoor Air Conditioner Cover will keep your home warm and your electric bills low. Another option is to remove the unit from your window. However, it can be difficult to remove without damaging it, and then you have to figure out a safe place to store it. Come springtime, you'll once again have to struggle to safely and correctly install it.


When not in use, your interior air conditioner can be an eyesore. Using a decorative indoor air conditioner cover provides both protection and aesthetic appeal, especially during the winter holidays.

Indoor air conditioner cover protecting a wall AC unit in the winter
Indoor air conditioner covers help prevent drafts during winter.

What are the Risks of Covering My Air Conditioner?

While covering your air conditioner has many benefits, you can end up damaging your unit if you are not careful or choose the wrong cover.


One common fear of AC covers is the development of mold, mildew, rust, and corrosion. This is caused by using a non-breathable cover. If you live in an area with heavy rain and snow, moisture is bound to get in even when covered. Choosing a breathable cover with side vents allows for proper ventilation and airflow. This means the moisture that sneaks in will quickly evaporate before mold, mildew, rust, or corrosion have time to set it.


Another danger is if your AC unit turns on while covered. If the cover is left on while the unit runs, the copper coils inside won't cool down after absorbing your home's heat. This means hot air will be pushed back into your home, and your air conditioner will run for too long, overheat, and break down.


It's easy to avoid this — shut off your air conditioner when it is covered. If you leave your thermostat on automatic, it may switch on during an unseasonably warm fall or winter day. Some units have outside power shutoffs near the condenser. Using the shutoff won't allow your AC to come on, even if you adjust the thermostat. This adds an extra layer of protection and helps remind you to take your cover off.


Another option is to use a Mesh Air Conditioner Cover. These covers can be left on while the unit runs as they allow all of the necessary airflow, but still provide protection from leaves, sticks, nuts, debris, and more.


What Should I Look for When Purchasing an Air Conditioner Cover?

When looking to purchase an Air Conditioner Cover, evaluate your needs. Do you live somewhere with harsh or mild winters? Is your unit beneath trees and bushes? Do you face frequent hailstorms? Questions like those will help you determine what type of AC cover to purchase.


In general, look for covers promoted as being breathable and water-resistant. Waterproof Covers don’t technically exist and are not breathable. This means that if water gets beneath the cover, it won’t be able to evaporate.


Trapped moisture causes mold, mildew, rust, and corrosion – the factors used when arguing against covering your air conditioner. Non-breathable covers are typically made of plastic, so look for one made of a commercial-grade vinyl or high-quality polyester.


reathability is vital when it comes to air conditioner protection. If you are looking to cover your entire unit, find a cover with mesh vents.


Carefully measure your air conditioner to make sure you purchase one that fits correctly. An ill-fitting cover won't work as well and could allow small rodents and insects to sneak in. If you can't find a cover that fits your exact dimensions, opt for one that is a little larger but has a drawcord, elastic hem, and/or buckle straps. While more expensive, you can also look into custom air conditioner covers for a perfect fit.


Alternative Solutions to a Cover

If you have a hailstorm or blizzard approaching and you don’t have time to get a cover, place plywood on top of the unit and weigh it down with bricks or rocks to keep it in place. Plywood is breathable enough to avoid mold and mildew within the unit. As soon as the storm is over, brush off the snow and ice and remove the plywood. You can also use this method in conjunction with a cover for extra protection.


You can also build or buy an air conditioner screen. The main purpose of these is to hide your air conditioner to make your yard more aesthetically pleasing. Screens don't cover the top of the unit, but will help block anything that the wind blows in from the sides. If you live in a mild climate and want to hide your outdoor air conditioner, pair a top AC cover with a screen for an attractive protection solution.


Cost Savings of Covering Your Air Conditioner

The Louisiana Cooperative Extension Service at LSU performed a study to investigate the monthly savings of keeping your AC unit clean and running efficiently. They found that you can save, on average, $32.76 per month. By getting yearly air conditioner tune-ups and keeping it covered during inclement weather, you could save up to $1,000 per year. Plus, using a cover will prolong your unit's overall lifespan, saving you thousands of dollars.



Air conditioners are all about efficiency. If it runs efficiently, you save money on your electric bill, yearly maintenance, one-off repairs, and full replacement. Whether you choose to use a cover just for winter or year-round, that little extra protection can pay off big time.



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