Will Rain Damage a Window Air Conditioner (Water Protection)

If you live in an area often battered by rain, you might be wondering, “Will rain damage a window air conditioner?”

Well, the answer is yes; sometimes it can. But it depends on the severity of the shower. Although having mild rain on your window AC is not always a bad thing, severe rainfall may cause potential damage.

The good news is you need not panic. With this guide, you’ll learn how to protect your window AC from rain – and the problems it might arise if your AC is left exposed.

Rain on Window AC: Why It’s Good For the Unit

Rain hitting your window air conditioner is not always bad. In fact, it can bring the following benefits:

Better Air Quality

Your air conditioner brings outside air inside your home. That said, if the air outside is filled with pollutants, there’s a good chance that these will enter your space as well.

Rain is good for your home’s air quality since it can dilute the pollutants and toxins from the air. That way, your AC gets to circulate cleaner, better air inside your house.

Improves AC Performance

Having your window AC unit in the rain can cool the coils and wash any dust away. Since these two factors can hamper your AC’s performance, the rain can help the unit to work better.

Cleans AC Unit Naturally

Rain can help remove dust and any other particles that might accumulate inside your AC unit. In essence, it helps clean your AC naturally – cutting your time for this chore in half!

When Is Your Window Air Conditioner At Risk?

While the rain brings many benefits for your AC, severe weather events may potentially harm the unit:

Will Rain Damage Window AC


Although there’s no need to worry about the window air conditioner when raining, flooding is bad. Too much water can adversely affect the unit’s parts and electrical components. Should this happen, it’s best to call an HVAC technician to check your AC and turn it on safely.

Windblown Debris

Apart from floods, heavy rain comes with strong winds that may blow debris to your AC. Leaves, branches (among many other things) can creep into your unit. Worse, fallen branches or trees may dislodge parts of the system, causing breakages and malfunctions.


As long as your AC unit is located in a well-ventilated area, the rainwater will evaporate and not cause any corrosion.

It’s a good idea to use a window air conditioner rain guard, but you should be careful in picking one. Make sure to choose a model that ensures good ventilation. If not, the rain guard will just end up trapping moisture – accelerating corrosion instead of actually stopping it.

Protecting Your Air Conditioner from Extreme Weather

It pays to protect your AC, especially if severe weather is headed your way. Here are some tips that can help safeguard your AC from the following elements:

Torrential Rain

Although rain can help your AC’s performance, your unit may get damaged under torrential downpours or flooding.

If you have an outdoor AC, it’s best to install it on a base or bracket to keep it out of reach of floodwater. The ground should be sloped to help drain the water and prevent any accumulation.

It’s also good to use a window air conditioner rain cover – and place your unit away from downspouts.

If your window air conditioner leaks when it rains, it means two things: either the drip pan is full, or it’s not draining quick enough (i.e., leaves and debris may be clogging the drain). If that’s the case, you need to remove these materials for your AC to drain effectively.

High Winds

Winds may damage your AC by blowing leaves, branches, and other debris into the interior of your unit. Worse, the wind can up topple trees – which could easily fall and break your AC.

To prevent these from happening, trim your trees right before the storm hits.


Outdoor AC – even indoor units installed on the roof, wall, and the ground – are at risk of a lightning strike. Although it’s hard to protect them from this surge, you may reduce the risk by installing an industrial-strength surge protector in your unit.

Another solution is to have your AC unit assessed by an HVAC professional. They can help prepare and protect your AC from damaging lightning strikes.


Hail – whether large or small – has the potential to damage your AC. The best way to protect your unit from this unpredictable weather condition is to install a durable window air conditioner rain guard over it. You can do this by purchasing a pre-made guard – or by using planks of wood to shield your AC.

Whatever option you choose, make sure that your rain guard permits enough airflow. If not, the trapped moisture can end up damaging your AC system by causing corrosion.

People Also Ask (FAQ)

What can I use as a window air conditioner rain guard?

You can protect your AC by using a pre-made window air conditioner rain guard. You can also make a DIY solution using treated wood or other weather-resistant material.

Can you run an air conditioner in the rain?

Yes, since a rainstorm won’t hamper the performance of your AC. In fact, you can feel more comfortable by doing this since the AC’s evaporator coils will introduce rain-cleaned/cooled air into your home.

Can you run window AC during thunderstorms?

Yes. However, you should be vigilant of any flooding that may occur outside. Should this happen, you need to turn your AC off right away to prevent any damage.

How do you get water out of a window air conditioner?

An AC has a drain that proactively removes water that accumulates in your unit. However, it may not be able to do its job well if it’s clogged with leaves, debris, and other dirt.

If your AC is not draining correctly, try to clean the drainage hole with a long wire or a baby bottle cleaner. Work it back and forth to dislodge the clogged material inside the drain.

How do you divert water from the outside window air conditioner?

You can divert the dripping water from your AC by attaching one end of the hose to the drip hole. Secure it with wire ties to ensure a snug fit. Lastly, place the other end on the area where you want the water to drain.

Where is the drain plug on a window air conditioner?

The location of the drain plug depends on the AC model. Old or large window units usually have their drain plus underneath. Some smaller models of window ACs, on the other hand, have a drain at the side.


Rain has advantages and disadvantages for all types of window AC units. For one, it may help improve AC performance – even clean it naturally. It can even help improve the air quality in your home.

Unfortunately, severe weather conditions may end up damaging your AC. Lightning, hailstorms, torrential rain, and high winds may damage it. Still, you can easily protect your window AC from the rain with proper maintenance – and a well-ventilated rain guard!

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.