Can You Vent an Air Conditioner into a Garage?

Perhaps there are no windows in the room to vent your portable air conditioner, or maybe you are looking for a way to temporarily vent an air conditioner until they are permanently installed. Whatever the reason, the garage has probably crossed your mind as an ideal place to vent your air conditioner. But can you vent an air conditioner in a garage without any issue? Here is what I learned after a few hours of research.

Although not ideal, you can vent an air-conditioner into the garage. However, the garage must be well-ventilated and have proper airflow to allow the hot air to move out; else, the air conditioner won’t function properly. To keep the garage ventilated while using the air conditioner, open the garage windows or door, or install a garage exhaust fan to blow the heat out.

We will take a look at some of the problems with venting the air conditioner into the garage. After that, I’ll cover with you the right way to do it to avoid any problem. Later in the article, we’ll discuss some alternative ways to safely vent your air conditioner instead of the garage. Let’s get into it.

Problems with Venting an Air-Conditioner into a Garage

There are quite a few things that can go wrong if you don’t set this up properly.

The garage can overheat.

The garage is not an ideal place to vent an air-conditioner. That’s because most garages are not well-ventilated. Only a handful of garages have windows or vents, and the garage is mostly not part of our home’s HVAC system. I’ve talked about this a lot on this blog.

The garage is usually not well ventilated because venting a garage is not a requirement by most building codes. It’s simply left to the builder to decide whether to ventilate the garage or not. I explained this, in detail, in my article about garage ventilation requirements. I recommend you check it out.

Why am I saying this?

Venting an air conditioner into the garage will release a lot of heat into it. That is how air conditioners work — they remove all the heat energy from one room and dump it in another place. So, all of the heat in the room you are air conditioning will be transferred into your garage.

And when the garage is not properly ventilated, this can make the garage extremely hot and uncomfortable. That is because there is no proper airflow to replace the hot air in the garage with fresh and cool air from the outside. And when the garage becomes too hot, they can lead to other problems, which leads to my next point.

Items stored in the garage can damage

The garage is not just a place where we store our vehicles. It also serves as a place where we store leftover paints, tools, and rarely used equipment such as lawnmowers and portable generators, and sometimes food items.

Most of these items are required to be stored in a cool and dry place. A cool temperature keeps them in a pristine condition for a long time. However, that immediately changes when you start venting an air conditioner into the garage. 

When your garage becomes too hot, all the electronic devices in the garage are the first to get damaged. Also, think about all the food items that will go bad as a result. All of the memorable Vinyl records and CDs you have stored in the garage are not left out too. 

Certainly, you don’t want these items to go bad, especially with your electrical and electronic devices. Because replacing or repairing them can be costly.

The air conditioner will not function properly.

Venting the hot air from the air conditioner into the garage will work properly — but only for a while if the garage is not ventilated. Why?

Over time, as the garage heats up, the air conditioner will find it harder and harder to discharge hot air into it. That’s because the place will be too hot to accommodate new heat. At this point, the air conditioner will not work as well as it should, and it will be harder to cool the room into the temperature you desire.

How to Properly Vent an Air Conditioner into a Garage

As we have already discussed, if you don’t do this the right way, it can lead to problems. All of these problems can be avoided if you follow these steps.

Open garage windows or door

The first thing you can do to reduce the heat is to open all the windows in the garage. Doing so will allow cool air from outside to blow into the garage and replace the hot air generated by the A/C vents. The more windows, the better. You need as much cool air in the garage as possible.

If natural passive air blowing through the window is not enough, then I recommend you open the garage door. Opening the garage door will allow a lot of air into the garage. 

The only problem with opening your garage’s windows and the door is, burglars and thieves have easy access to your house. They can simply enter your home through the windows or the door and steal anything they want — easy pass. This means you can’t keep them open for too long, and you don’t have to forget you left it open.

So, yes. Opening the garage windows and doors will increase airflow in the garage and remove all the heat by the A/C from the room. However, it is not an ideal solution because of security concerns.

Install an Exhaust Fan

If you want to vent an A/C into the garage, installing an exhaust fan in the garage is the best way to keep the garage cool.

Why do I say this?

Opening windows and the door will allow air to naturally blow into the garage. This is known as natural passive ventilation. However, the amount of air that gets into the garage depends on the wind’s speed and direction.

In some days, there will be a good amount of air blowing into the garage to increase airflow, and in some days, that won’t happen.

Instead of relying on natural passive ventilation, an exhaust fan will force airflow in the garage. An exhaust fan will help remove all the hot air in the garage and replace it with fresh and cool air from outside. It will be as effective whether the wind is blowing or not. Exhaust fans will also remove bad odor in your garage.

Using exhaust fans instead of opening the windows and doors will solve the security issue. You don’t have to keep the garage windows or door open to allow air to enter. You will still be able to use your air conditioner in the night, and not worry about thieves invading your home.

Alternative ways to vent an air conditioner

Ideally, an air conditioner is supposed to be vented outside. I believe we are all familiar with that. So, if there is a way for you to vent it outside, it’s a no-brainer to go for that option. Here are alternative ways you can vent your air-conditioner

Through a window

One of the best places to vent an air-conditioner, especially a portable A/C, is through a window. That’s because there are several vent kits made for windows that allow you to discharge the hot air from the A/C outside.

This kit usually consists of a 6-inch hose, a window adapter, and an adjustable window kit. When installed correctly, the air conditioner’s hot air will be discharged through the window without outside air getting into the room. And there are different types of window vent kits for every kind of window.

A perfect example is Gulrear Portable A/C Vent Kit (on Amazon). This particular type is made for both vertical and horizontal sliding windows, and it’s been proven to work very well. It also comes with an instructional video that is easy to follow.

Gulrear also makes this particular Vent Kit (also on Amazon) for traditional windows with hinges. This works differently from the one I’ve already described.

This can be an excellent way to vent your air-conditioner, instead of inside the garage.

Through the wall

If there’s no window in the room, you can vent the air conditioner through the outside wall. This is a relatively simple project that you can do in 15 minutes or less. 

Find a free space near the wall where you can position the air conditioner, and then a good location on the wall that you can drill a hole into. You’ll need a 6-inch hole saw and a drilling machine to drill a hole in the wall. Once that’s done, simply slide the 6-inch hose inside the hole and then attach a vent cap on the hose. 

The vent cap will prevent moisture, debris, and dust from outside to enter the air conditioner. This vent cap on Amazon has vents that only open when the air conditioner is working. Once it stops, it seals to prevent anything outside to penetrate through.

 High Ridge Handyman did an awesome job in this video, explaining how to vent an air conditioner through the wall.


Ideally, an air-conditioner should be vented outside. However, if that’s not possible and you want to vent it into a garage, you need to ensure that the garage has proper airflow and is well ventilated. You can improve the garage’s ventilation by opening the garage windows or door, or by installing an exhaust fan, which I highly recommend.

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