How To Vent A Portable Air Conditioner Without A Window

When faced with cooling a windowless room, the question of how to vent a portable air conditioner without a window becomes the problem that can be solved.

It is of course possible to run a portable air conditioner inside a windowless space when there are other venting options available.

Let's take a look at how this can be accomplished when a window is not available to connect a portable air conditioner's exhaust vent hose to.

It's worth mentioning that over 80% of portable AC unit customers will install the exhaust vent hose through their window using the manufacturer's fixing kit, which also helps to seal the window.

When Venting a Portable AC is Not Possible

portable air conditioner vent optionIn rare cases, venting a portable AC in a room without a window is just not possible.

The interconnectedness of these coolers require a window or other access to the outside of the building. However, there exist rooms deep within building that have no access to an outside wall.

In this case, unless it is possible to vent through the ceiling, such a room becomes a major headache to keep cool as there is no way for the exhaust hot air to be vented to the outside.

One solution is to use a ventless air conditioner (which is really an evaporative cooler), along with a dehumidifier while also keeping a door open. This can help to keep you cool in a windowless room, but it is not ideal.

What Happens if an AC Unit is Not Vented?

Portable air conditioning equipment must be used with a vent, or means of carrying the hot air away from the building.

There are some options for portable air conditioner venting, but if the hot air is not exhausted outside the building, the heat will build up and cause a net temperature increase inside the room being cooled by the AC unit.

The unit can be turned on and it will run as normal. However, because more hot air is being vented into the room than cold air, the temperature will not be lowered.

Yet all is not lost if there is no window to act as the venting gateway to the outside. Even if a portable AC is installed in a windowless room, there are other ways to vent it.

Five Alternative Portable AC Venting Options

Here are five optional ways to vent a portable air conditioner without using a window.

This just goes to show that it is possible to vent a portable air conditioner in a windowless space.

Venting Through the Door

There may not be a window in some rooms, but there will be a door.

A free standing air conditioner can be vented through a room's door, but be aware of what is on the other side of that door.

There may be trouble achieving the temperature difference you need for the cooler to work if the door leads into another room or a hallway.

However, if the room has a balcony with a door leading out onto it, the air conditioner can be vented directly outside through this door.

Sliding doors that lead to open air provide a simple solution because it is possible to install a sliding door seal. The temperature difference needed for a regular or self evaporating portable AC unit to work as well as if it were vented through a window.

Specialized kits can be used with any size sliding door (up to 150inches), and are approximately 6-8in wide. It is relatively easy to install the kit on a sliding door and fix the vent.

Venting Through the Wall

Portable air conditioners that are not able to be vented through a window can be vented through an external wall.

It will be necessary to create a hole in the wall if you wish to install an AC unit's vent hose. A hole can be drilled in a wall if you have handyman skills and possess a power drill.

The hole's diameter should match the diameter of the hose venting the portable air conditioner.

This is a more common solution for portable air conditioners with a single hose. While dual hose portable AC units are less energy-intensive and desirable to prevent internal pressure problems, drilling two holes into a wall is a bigger job.


Before you start drilling, ensure that the vent is located on the correct wall.

For example, reinforced steel walls are not recommended. Only a professional can drill through them.

Avoid thicker, denser walls. A thin wall of low-density concrete is the best option for venting a portable cooler into a windowless space.

A room with a vent hole already installed in the wall for venting is of course the best!.

Venting Through the Dryer Vent

Dryer vents are generally the same size as portable air conditioning appliance vents.

A vent hose for a portable air conditioner can be attached to this type of vent hole negating the need for a window if you're using dryer vents.

If you still need to vent your dryer through the wall in the same room as the AC, you will need to manually switch vent hoses between the two appliances as needed.

A room with a dryer vent has the disadvantage that it is usually not a living space like a bedroom or living room that would require cooler air.

Another limitation is the 6ft fully extended length of the vent hose that most portable ACs use.

Venting Through the Ceiling

Using a false or drop ceiling is a common method of venting a portable air conditioner in a windowless office.

It is possible to vent an air conditioner through a drop ceiling if there is no window.

A drop ceiling is a must, yet where modern houses do not have drop ceilings, older, high-ceiling houses sometimes do, or it can be installed. However, most modern houses are small and unlikely to have windowless rooms that require the extra cooling of a portable AC.

Ceiling venting for air conditioning is popular in offices. Cubicle offices can heat up a lot in the summer. A portable 10,000 BTU air conditioner can be used to cool the office and be vented through the ceiling if the central air conditioner is not sufficient.

A drop ceiling venting kit is used to install the venting pipe. These kits can extend the hose by up to 10 feet and fit all portable air conditioners.

It's a viable solution for rooms that don't have windows, although this kind of vent system can appear unattractive.

Venting Through the Chimney

Chimney venting, which is less common, is an alternative way to vent a portable AC. It does require some additional work.

First, there must be a serviceable chimney above a fireplace in the room.

It may not be easy to install AC venting through a chimney, especially if the room is on the ground floor and there are two or more floors the chimney has to service. This will mean a long chimney and therefore a long, fixed vent flue that extends the full length of the chimney.

It is advisable to speak to a professional to ensure that all safety precautions are met.

Chimney venting is less of a problem in smaller, single floor cottages, where the chimney length is small.


It is not always difficult to vent a portable air conditioner when a suitable window is not present.

You can make use of sliding doors, or drill a hole in the wall or even use a chimney if there is one. In any case, thinking creatively about how to vent a portable air conditioner can result in some creative solutions.

[Back to TOP]