Can a Window AC Unit Be Used Without a Window?

Summer is the most awaited season of the year — but it can also be unbearably hot. So, when the time comes, you want to be able to escape into the cool comfort of your home. An air conditioner is a perfect way to achieve that. But what if your room has no windows? Is a window unit still the best option? 

Although it’s possible to use a window air conditioning unit without a window, you’ll need some way to release the hot air from the unit. Options include using a door out of the room or drilling a hole in the wall. Building a window may be the best solution.

Let’s look at how window AC units function, whether you can use them without a window, and some alternative air conditioning options.

How Does a Window AC Unit Work?

Window AC Unit

We all can admit that the summer season can be draining, despite the great weather and opportunities for fun outdoors. Sometimes the heat is too much to take, so an air conditioner can save the day.

But before we get to know how AC works, let’s try to find out what an air conditioner is. A window AC unit is the most simple and basic AC available.

All the components, such as the compressor, condenser, expansion valve or coil, evaporator, and cooling coil, are enclosed in a single box. On top of that, the unit perfectly fits in a window. 

Window AC is a popular cooling solution for small indoor spaces. The unit has a blower and fan that helps to expel warm air and propel cool air into the room.

Unlike a portable AC, a similar system on wheels, the window AC unit is better for tight spaces and easier to install. Just mount it on a window and plug it into an outlet.

Now, let’s dive into how window AC units work:

Air Extraction 

Once you turn on the AC unit, it extracts the air from the room through its fan. The air is drawn into the grill and passed through a filter to remove the airborne particles. 

Refrigeration Process

Apart from the air extraction, the unit initiates the refrigeration process once the AC is on. This process involves the refrigerants taking on and then releasing the heat. It first converts the hot water to gas and then cold liquid. The temperature of the liquid is shallow compared to refrigerants. 

Decreased Temperature

The cold refrigerant starts to flow into the AC’s indoor coil during the refrigeration cycle. The hot air that the unit sucks is passed over the coil as it flows. This process will result in a decrease in the temperature and a rise in the refrigerant temperature.


Once the temperature of the refrigerant rises, it becomes a vapor. This vapor goes through a compressor and nudges to a condenser coil. As it enters the coil, the vapor undergoes condensation.

It loses the heat being released outside and converted into a liquid. This method completes the refrigeration cycle.


The cold refrigerants now pass through the expansion valve and operate a process that decreases the liquid’s pressure by giving it a narrow path before emitting it to open space. During this process, the liquid’s temperature further drops and then returns to the evaporator coil that contacts the air released into the room. 

Release of Cool Air

As the hot air meets the cold liquid, the temperatures drop. The atmosphere will be pushed through a cold coil and back to cool the temperature of your space. 

Now that you know how the components and parts of window AC work, we’ll look at the holistic view of how these units operate precisely. Windows ACs work through two cycles. First is the room cycle, which explains the cooling of your space. The second is the hot air cycle, which is how the AC will cool down. 

The Room Cycle

The window AC’s purpose is to get the air moving. Once the window AC is on, its blower starts up, followed by the compressor. The cooling coil (or evaporating coil) will drop when the compressor starts. The blower starts to pull the warm air with dust particles and then filter the air. 

Two things happen here: First, the coil’s temperature is much lower than the room air, and the coil will absorb the warm air. This process will result in the room having chilly air.

Second, the cool coil is lower than the room’s dew point, causing it to form in the cooling coil area. This will help remove the moisture from the air, decreasing the humidity. A continued air cycle will help the room to have fresher air.

The Hot Air Cycle

The hot air cycle focuses on the air outside the unit. You will find the back of the AC is always hot. This heat is caused by the hot air pulled in by the fan. The air then goes to the condenser. The refrigerants inside start to heat up. This is the accumulation of heat.

The refrigerant must be cooled down after the absorption of the hot air. Then, it will enter the expansion valve and then the evaporator for a cooler temperature. Later on, the air will blend with the fresh air and push over the condenser. Then the cycle continues.

Does A Window AC Have to Be in a Window?

Manufacturers designed and created window AC units to be installed and mounted in windows. All the byproducts that these units produce, such as water and warm air, should be redirected outdoors. 

However, a window AC unit doesn’t always have to be in a window, as long as the warm air and water have a way to be expelled outdoors. You can always frame a hole as a window for venting the air.

But there are some problems with this. If you only need your window AC during the summer, you need to remove it before the winter season. Then you still have a hole left over.

It would be helpful if you had a way to capture the heat coming from the rear of the unit and vent it somewhere else. If you plan to remove the unit, it can be challenging to cover the hole.

Adding a window is the most straightforward solution. After all, you can hit two birds with one stone when you add a window. You can have window AC in the summer, and you can seal and close the window during the cold season. 

But if you can’t build a window, there are other ways to use a window AC. Some people vent the warm air through their garage or an empty room, where heat isn’t an issue. Some use ductworks to vent the air outside.

How Do You Use a Window Air Conditioner Without a Window?

Square air conditioner in the apartment

While it may be true that venting a window AC unit without a window is quite hard, this doesn’t mean that it’s impossible. Here are three easy ways to use a window AC without a window:

1. Convert the Window AC to a Portable AC 

Converting a window AC unit to a portable AC unit sounds like a DIY option. As you may notice, portable ACs are just like window ACs. The only notable difference is that they have a built-in flexible duct and kits to vent the extracted air outside. 

2. Vent the AC Using the Door 

Since the room doesn’t have a window, the best option is to vent the extracted hot air through doors. But be careful about where these doors may lead.

If they go to another room, then this can be pretty tricky. It would be best if you had a door that leads outside.

3. Drill a Hole in the Wall

Other options include creating a hole in the wall of your room. You can vent the absorbed humid air from the wall outside the house. If you’re especially handy, this is a quick solution.

Otherwise, you may opt to choose and go for through-the-wall air conditioners.