Must a Portable Air Conditioner be Vented Out a Window?

It is often questioned whether a portable air conditioner must be vented out of a window or indeed any other form of ventilation opening in an external wall.

To find out the reality of this problem, I will delve into the subject and provide a straight answer along with some alternative solutions.

Before I get into this, it is important to realize that all air conditioners will produce hot and cold air during the refrigeration process that creates the cooling effect in a room.

venting a portable air conditionerThe object of air conditioning is to provide cold air to circulate around a space to keep the indoor climate comfortable during the hot months of the year.

Since the hot air is not welcome inside, it must be removed from the building, which is achieved using the necessary form of ventilation.

Air Conditioners and Hot Air

Air conditioners have a way to remove hot air from the cooling unit in a way that does not allow it to be released into the room being cooled.

Fixed AC equipment utilizes installed ducting, which connects the cooling unit to the outside unit via an external wall.

The internal unit (compressor/dryer), produces hot, moist air. Moisture from the interior air is also removed.

The hot, humid air that results is drawn through the ducting is pulled by the fan at the exterior unit. It is then released to the air outside where it is dispersed.

This is how central air systems (HVAC), as well as mini-split ACs cool indoor air.

PTAC, and VTAC units work in a similar manner, while window AC units vent exhaust air directly through their external vents, with all processing being done in a single AC unit.

Portable ACs and Hot Air

Portable air conditioners are different in the way they remove the hot air created inside the unit. They use a flexible vent pipe that needs to be connected to an outlet in order to remove any hot air from the area they are cooling.

Portable self-evaporating AC units are also subject to this requirement. Because they are portable, or not fixed in place, the flexible exhaust hose is necessary. They can be moved around and the hose connected to the wall outlet.

Window Outlet or Wall Outlet

A window is the most popular way to vent hot air from a room. It is relatively simple for most people with some handyman skills to attach a specially-designed outlet vent to a window.

Although some people may not like installing window fixing kits or have an ugly trailing hose extending from the unit to a window, it is easier than having to drill through an exterior wall.

A wall vent can be used in certain situations where a window would not work or is not possible. It is easy to install a wall vent if one is already in place. If there is not, it's easy to make a hole in the wall.

Other Venting Options

A window or an exterior wall are the best options to vent a portable air conditioner through. However, there are other options if you don't have a window or can't drill a hole in an outside wall.

If the room has a door opening to a balcony this can be used. Although the installation might not be straightforward, a professional should be capable of doing it.


In older homes, a chimney may be available, which is another option for venting.

To ensure that hot air can escape unimpeded, however, the chimney must have a long flue installed. Professionals should perform this type of work.

Another option is to use existing ductwork if you have it, or install a fixed conduit through a false ceiling (which is more common in commercial and office buildings).

No Venting Option

If there is no way to vent an AC portable in a room, there is another option for staying cool.

You can buy an evaporative cooler (ventless air conditioner) that does not produce hot air and therefore dose not need to be vented outside.

This option is subject to restrictions. It is necessary to live in an area with low humidity. The room that you want to cool must also have a window which can be opened to allow air circulation.


The question of whether portable air conditioners should be vented from a window or not is answered by the following: A window is best if it is available. However, there are other venting options.

All options should be explored, as long as the hot air can escape the room. It is not recommended to run a portable AC in an area without venting to the outdoors because this will actually cause the temperature to rise, not fall!

A portable air conditioner should be vented to the outdoors in one of the ways described above, although a window is the best and most widely used of these.