How to Vent a Portable AC Without a Window (DIY Guide)

A portable AC unit is a great alternative to a cumbersome window unit. Modern portable air conditioning units are just as effective and have the added benefit that they can be moved from room to room.

If you are using a portable AC, then you need to make sure it is vented. So we put together this guide on how to vent a portable air conditioner without a window.

Ways to Vent a Portable AC Into a Windowless Room

There are 5 main ways that you can vent a portable air conditioner in a room without a window. Each method has its advantages and drawbacks.

Venting through a wall

You can vent an exhaust hose through a wall into a side room or to the exterior of your house. To do this, you need to cut a circular hole in your wall, feed the hose through the hole, and seal the hole with caulk or silicone. This method works very well, but you have to cut into the wall.

This might not be a viable option; for example, if you are renting an apartment then purchasing a through-the-wall AC might be better.

Venting through the Door

If you have a sliding patio door or something similar, you can vent your exhaust hose through the door. To do this, you need to get a portable AC sliding door vent kit, attach the hose to the exhaust port, and place the kit in the gap between the door frame and the door. These kits allow your unit to vent through the door but also allow the door to stay sealed and shut.

Venting through the Ceiling

You can also vent through drop ceilings in rooms that do not have any windows or doors outside. Venting through the ceiling requires you to remove a tile in your drop ceiling and fit a custom plexiglass seal to fill the space between the hose and the edges of the tiling. Portable air conditioner ceiling vent kits are relatively cheap and widely available online and in hardware stores. The method is not as common in residential homes but is in commercial buildings.

Venting through home AC Vents

You can also try to vent your AC unit through your home’s built-in AC vents. You can feed your AC exhaust hose through the AC vents and let them take care of it. The only problem with this method may be that your home’s AC vents are not large enough to fit the exhaust hose, and air leaks out. Thus, this method may not work for everyone and should only be tried if other methods have not worked yet.

Venting Through Home AC Vents

Venting through the Chimney/Fireplace

Another method is to vent through a chimney or fireplace. This can be a viable method if there are no doors or windows and the walls are too thick to cut through. You will most likely need to make a custom plexiglass pane to fill the gap between the hose and the walls of the chimney. This can be an effective method if you have no other alternatives.

DIY or HVAC Technician? When to Call an Expert?

In most cases, venting a portable AC is not a difficult task, and there are several kits designed specifically to vent an air conditioner through a door or window.

However, if you have to resort to options that involve making significant modifications to your home, such as cutting a hole in the wall or the ceiling, we recommend getting the advice or services of a professional HVAC technician, unless you have prior experience working with AC units.

The Do’s & Don’ts of Portable Air Conditioners

Here is a quick list of what you should and what you should not do when installing portable air conditioners.

  • Determine the correct BTU size. Generally, a portable AC unit should have 20 BTUs of power for every square foot of living space.  
  • Properly place the exhaust hose. The exhaust hose needs to be placed so that it does not leak into the room that is being cooled.
  • Invest in good filters. A good filter will improve the longevity of your air conditioner unit and improve its efficiency. You should change the filter once every 6 months or so.
  • Consult a professional if unsure. It is better to call a pro if you don’t know what to do instead of winging it. You might break something then be on the hook for even more expensive repairs.
  • Ignore maintenance. Like any other piece of hardware, an AC unit needs to be maintained and repaired every now and then.
  • Use an outlet without enough power. If the outlet you use does not give enough power, then the AC conditioner will not be as efficient and won’t cool.
  • Place your unit in a sunny spot. If you put the unit in a very sunny location, then there is the risk that it might overheat and damage.
Do's and Don'ts of Portable AC

People Also Ask (FAQ)

Can I use dryer vents or an attic to vent a portable AC?

If the dryer vent is large enough, then yes, you can use a dryer vent to vent a portable AC unit. If it is not large enough, we would not recommend using a dryer vent for your AC unit.

Can a portable air conditioner work without the hose?

No, a portable air conditioner will not work without a vented exhaust hose unless it is explicitly designed as a ventless AC unit. With a hose, there is nowhere for the hot air to go, so it stays stuck in the room.

How long should a portable air conditioner sit before turning it on?

In general, you should let your air conditioner unit sit for about 12-24 hours before turning it on. You need to give it time, so the refrigerant and compressor oil settle to the bottom of the reservoir.

How long does a portable AC take to cool a room?

It depends on the size of the room and the strength of the AC unit. AC unit power is often measured in BTUs. As a general rule of thumb, 20 BTUs are suitable for one square foot of space.

How many hours should a portable AC run per day?

Generally speaking, it is safe to keep your portable AC unit running all day. It might actually be more efficient to keep it running rather than turn it on and off when you come and go.


Portable Air conditioner units a very useful and worthy investment. They can be used instead of a clunky window unit. But they need to be used correctly. There are many ways to vent a portable AC unit without a window that will make it run efficiently.

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.