How To Vent A Portable Air Conditioner Without A Window: 5 Ways

Can you use a portable air conditioner in a windowless room? Of course you can. There are 5 ways how to vent a portable air conditioner without a window.

Portable air conditioners and though the window exhaust vents go hand-in-hand. In fact, more than 80% of people who buy a portable AC unit install the exhaust vent out of the window.

What is more, the out-the-window installation is so popular that many producers give you a free window seal kit for portable air conditioners.

However, in some situations venting your portable AC out of the window just isn’t possible. Because of how well these AC units and windows go together, the question of ‘How to vent a portable air conditioner without a window’ doesn’t seem to have a clear answer. At first.

What happens if you don’t vent a portable AC unit?

It is impossible to use a portable air conditioner without a vent. You can turn it on and it will even run normally but it won’t decrease the temperature of the room.

There are several ways of how to vent a portable AC unit even if you put it in a windowless room.

We’ll present 5 ways how you can use a portable air conditioner without a window. Mind you, without a window, venting a portable air conditioner is more difficult (but not impossible).

In a windowless room, you can vent a portable AC through:

1. Vent A Portable AC Unit Through The Door (Bonus: Sliding Door)

There are windowless rooms but there are no doorless rooms. Every room has a door, and you can vent a portable air conditioner through the door. Using door venting is the most common way of venting a portable air conditioner without a window.

Obviously, it’s important where those doors lead. If it leads to a hallway or another room, you might have difficulty getting the required temperature difference that would make the air conditioner effective.

If, on the other hand, you have a balcony door, you can vent an air conditioner directly outdoors.

Here’s the best case:

Sliding doors. Sliding doors usually lead into an open air. Installing a sliding door seal is easy and you will have the required temperature difference that will make a portable AC unit as effective as if you would vent it through the window.

without a window you can vent portable AC unit through a sliding window
Sliding door seal with the installed hose through it; the most common way to vent a portable AC unit without a window.

For ordinary doors, installing the 6 feet portable AC vent might be tricky. With a sliding casement door, installing the ventilation is easy with a sliding door vent kit.

These kits are designed to fit any sliding door dimensions (up to 150 inches), are about 6-8 inches wide. You install it on the window, fix the vent and you can vent a portable air conditioner without a window.

This works for pretty much all units. You can check the best portable air conditioners here.

2. Installing A Portable AC Vent Through The Wall

Like doors, every room has walls. Any portable air conditioner that cannot be vented through the window, can be vented through the wall.

Obviously, most rooms don’t have 6-diameter holes in their walls. If you want to install an AC unit through the wall, you have to make a hole yourself.

drilling a hole in windowless room wall to vent a portable air conditioner
Drilling a hole in the wall is a requirement for venting a portable AC through the wall.

If you’re a DIY enthusiast and own a power drill, you can drill a hole in the wall. The diameter of the hole should be the same as the diameter of the hose that vents the portable air conditioners. Alternatively, you can install a through-the-wall air conditioner.

This method is more often used for single-hose portable air conditioners. Two-hose portable air conditioners are more energy-efficient but nobody really likes drilling too many holes in their walls.

Here’s what you have to be careful about:

Prior to starting the drill, make sure to choose the right wall for the vent. Reinforced steel walls, for example, are a bad choice; only a professional can drill through them. Don’t choose thicker walls. The best-case scenario for a windowless room is to vent a portable air conditioner through a thin wall made out of low-density concrete.

The most elegant solution, however, is a room that already has a hole for a vent in the wall. You might even be using it for laundry:

3. Vent PAC Through The Dryer Vent

There is literally no difference as far as dimensions go between a dryer vent and a portable air conditioner vent.

If you are using a dryer vent, you can use the same hole to install a hose and vent a portable air conditioner without a window.

In fact, most window seal kits for portable AC units you get can also be used to vent a dryer. What is more, venting a portable AC through a dryer vent is the most common advice AC producers give when asked ‘I don’t have a window, how can I vent a portable air conditioner?’.

The drawback with venting a portable AC through the dryer vent is that you’re conditioning the air in the room with a dryer. And that’s usually not a bedroom, living room, or any other room where you would need cooler air.

The 6 feet vent hose most portable air conditioners have is a limitation as well.

Advice: You can buy a longer hose. You can get a 20 feet hose, install it through the dryer vent hole, and connect it with the portable air conditioner placed in the hallway, or even the living room. This may decrease energy-efficiency (EER rating on specification sheets) but you will be able to vent a portable air conditioner without a window with ease.

4. Ceiling Venting (Most Commonly Used In Windowless Offices)

If you don’t have a window but you have a drop ceiling, you can vent a portable air conditioner through the ceiling.

The drop ceiling is a requirement here. Most modern houses don’t have them. A drop ceiling is found in high-ceiling older housing.

Ceiling venting is popular in offices. More often than not, offices have a drop ceiling that’s not being utilized. Cubicle offices, for example, can heat up quite a bit during the summer. If the existing air conditioner system (usually central air conditioning) isn’t sufficient, you can use a portable 10,000 BTU air conditioner, for example, and vent it through the ceiling.

To install the venting hose, you can use a specialized drop ceiling venting kit. These can extent the hose length by as much as 10 feet and are universal; they fit any portable air conditioner. Here’s how venting a portable air conditioner through the drop ceiling looks like:

venting portable AC unit through the drop ceiling

All in all, it’s a neat solution for rooms without windows, albeit the whole vent setup doesn’t look pretty.

5. Venting Through The Chimney (Seldomly Used)

Chimney venting is a less frequently used way to vent a portable air conditioner without a window. It does require quite a lot:

First it all, you have to have a chimney in your house. It has to be unused (during the summer it usually is).

Installing a hose through the chimney is quite tricky, to be honest. It would be best to talk to a professional in order to check off all the safety concerns. The installation will also require the use of a very long hose (at least the length of a chimney).

Chimney went is most often used for smaller cottages where the chimney length is minimal.

You Need To Be Crafty

Venting a portable air conditioner without a window is tricky. If you don’t have sliding doors or if you’re not prepared to drill a hole in the wall, you really need to get creative and crafty with how to set up venting.

Some DIY guys have their own special methods of how best to vent a portable AC. If you have your own way, you can share it with all of us in the comments below.

58 thoughts on “How To Vent A Portable Air Conditioner Without A Window: 5 Ways”

  1. I have built a 10×12 pet grooming shop for my wife in a section of our garage. I did install a small window. I’m wondering how it would work if I vented into the remaining garage space. It does get quite warm in the garage when the Sun hits the door in the afternoon. Thank you!

    • Hello James, that could work but the remaining garage space will effectively be heated up. If you don’t need that garage space, you can certainly do it. If you do need it, this type of venting will turn it into a sauna (high temperature, high humidity).

  2. So if I’m just trying to cool a bedroom it might be ok if I vented into the hallway & used a fan to then push the hot air to the other end of the house?

      • Can I use the vent in the room were Central heating and air goes it’s currently not working but I guess I can use the vent correct will it burn my carpet

        • Of course, you can vent a portable air conditioner through the floor. You’ll need the hole in the floor and vent it through there. Just directing the vent to the floor won’t help, though.


  4. Would it be possible to vent through the heating vents. I live in Colorado and no central air conditioning, but have central heat.

    • Hello Kay, that would be the 6th option! If you have vents that vent outside the house, you can definitely channel the portable AC vent into those and the hot air will be dissipated outside. Just make sure you vent it in such a way that the hot air leaves the house; if the hot air would circulate through your heating vents, it would defeat the purpose of cooling altogether.

  5. We’re trying to finish our walkup attic and were wondering if we could vent the portable unit into the return duct work that already exists in the space. Is that possible?

    • Hello Jenny, you can use the existing ductwork. Make sure that the portable AC venting through the ducts will be directed outdoors. If the hot air in the ducts circulates throughout the house, you will actually warm the house up. Look at where the ducts are vented outside and install the portable air conditioner venting there. Hope this helps.

  6. Using the drop ceiling method, can I just cut a circular 6 inch hole in my bedroom ceiling (not a drop down ceiling) get the extender hose and run the hot air to the attic?

    • Hello Robert, you can do that. Just be aware that your attic would be heating up; if you can, you can open windows there. However, this drop ceiling method will effectively cool down your bedroom.

    • Hello Dana, if the vent is directed outside, you can do that. If the hot air from the portable AC will be vented throughout the vents, it will heat your house instead of cooling it down.

  7. I want to cool my garage. can I vent it into a soffett that goes to the attic and it eventually finds its way outside? Do I need a drain to the outside for condensation?

    • Hello Dave, you can cool your garage and use ventilation to the attic. Just keep in mind that the attic will be heated up. You can drain the portable AC anywhere really; a sink, a bucket, etc., it doesn’t really matter or affect the indoor temperature.

  8. In my garage there is no windows, wall, nor ceiling vents, but my water heater tank has a vent hose at the top of the heater. Could I add a splitter above it and hook the portable A/C unit hose to it?

  9. Something to consider. Most new portable air conditioners use 6 inch diameter hoses, not the 4 – 5 inch ones a dryer uses. So venting through a dryer vent in your wall will work, but it will also cause your AC to work harder to push all that heat through the smaller opening. So, be careful to use a vent the same size as the exhaust hose off the AC so that it all works efficiently with out shortening the life of the AC. Just saying.

    • Hello there, this is a superb insight. If you attach the 6-inch hose on a 4-5 inch hose dryer uses, there will be a pressure build-up due to airflow restriction. This will in turn, just as you have neatly put, force AC to work harder, shortening its lifespan. If anybody wants to know more about how the restriction of airflow can lead to pressure build it, you can check out the Boltzmann equation that determines this flow (a bit of complex physics included).

  10. Looking to use a portable AC unit in our condo, we have wall access from a gas fireplace we removed , only thing the vent is approx. 4.5 ‘ or 54″ , is there a limit on how high you can put the vent ?? Thanks !

    • Hello Bill, the cross-section of most portable AC vents is about 6″. Do take that into consideration. Also be careful that the hot air you’re going to vent isn’t being recirculated within your condo; that will heat the whole place up. If you account for these two things, it is possible to vent an air conditioner via the wall access from a removed gas fireplace.

  11. I have a dual hose ac unit. Can I use the drop ceiling method in my basement?
    If yes, do I need to put both hoses into the ceiling? Would I need to use something to expel the hot air out of the house above the drop ceiling?

    • Hello Chris, you can use the drop ceiling method in the basement. In the case of dual hose portable AC, one hose is to vent out hot air (that one has to be vented thru the ceiling) and the other is to pull in the fresh air. Now, if you don’t have access to fresh air, you don’t have to vent it; effectively you will have a single-hose AC; not a perfect system but pretty much optimal in your situation. The drop ceiling has to be vented out of the house, of course. You want to minimize the path of the hot air within the house; the quicker you can get rid of the exhaust air, the more efficient cooling you’ll have.

    • Hello there, that won’t work. The air in the bag will just be hot and in some minutes the bag will be full and it will rupture.

  12. I have a bedroom with an outside door. If I get a dryer vent kit and install a “dryer vent” in this outside door, would that work?
    I’m thinking about using the door for two reasons:
    1. It would be easier to cut a hole in the door than the wall.
    2. If I decided to stop using the portable AC unit, for whatever reason, it’s a lot easier to replace the door than trying to repair the wall.
    What is your opinion?

    • Hello Rug, it’s definitely less harmful to cut a hole in the door than in a wall. The dryer vent is a bit iffy; most have a 4″ cross-section and portable AC hoses have (most of them) a 6″ cross-section. You can channel the portable AC hose into the dryer vent hose but the unit will be a bit less energy-efficient. Overall, it’s a good setup if you don’t have other means to ventilate a portable AC.

  13. Our central air unit just got hit by lightning and we want to set up our portable air conditioner until it is fix. We live in a mobile home where the in take is in the floor. Can I vent the portable air conditioner through the floor in take vent?

  14. My house is brick veneer construction which had a gap between the outside brick and inside plasterboard.

    What effect would simply making appropriately sized hole in the interior drywall where the hot (dry?) air goes up inside the space to the roof space where it’s hot anyway. Cover hole when not required in the winter.

    Quotes for split system aircon mind blowing plus no available wall space

    • Hello Pamela, you’re right, split system air-cons are vastly more expensive than portable AC units. That hole can very much be utilized to vent a portable AC unit. If the roof space is hot anyways, adding the hot and dry air won’t make a difference, and you will have adequate venting for the portable AC unit.

  15. I live in a mobile home and the exhaust hose goes out the window into my enclosed front porch it makes it really hot what should I do to get the heat out of my front porch

    • Hello Tiffany, that won’t help. You will have hot air bubbling out of that water. Having no windows is truly a problem if you want to install a portable air conditioner.

  16. HI

    I have the exhaust blowing out my window and its fine. But I cant have the water drain hose hanging out my window.

    Can I make a hole in my exhaust hose, and put the drain hose into it? That way the hot air will blow out the water and probably just disappear from the heat.

  17. I live in an apartment building with no air conditioning. I bought a portable evaporative cooler (7,000 BTU) and it does pretty well until the temperature outside gets to over 90 degrees. I’m considering getting a portable unit that is 12,000 BTU. My current unit is vented out the window. There are 2 ceiling vents in the apartment. One in the bathroom and one by the front door. What I’m wondering is, could I vent either the one I have or
    One the I’m considering getting, through one of those ceiling vents?? Thank you for your time and help!!!

    • Hello Andy, a very good question. Theoretically, no. Practically, you always get something like 16 ft long exhaust vents. The longer the vents, the more energy AC would need to push that air out, well, at least theoretically. Quantify these energy losses is anything but a piece of cake.

  18. Hi there
    In the storage room above my garage, we have an exhaust fan and two vents but no AC. Would it be possible to run the portable ac hose to the exhaust vents?

  19. I have a closed up (fireplace) chimney in my bedroom. (raccoons liked it). Can that be used to vent a portable AC unity. My master bedroom has a vaulted ceiling with no insulation, and gets so hot in the summer. My House AC cannot keep up to cool the whole upstairs. The basement is frigid.. I hesitate to cover all downstairs vents to force all air upstairs for fear of freezing the compressor.

    • Hello Nancy, considering how much the raccoons like it, does that mean that the chimney itself is vented? If so, you can easily vent a portable air conditioner into the chimney. If it’s fully closed, you can’t really vent through there.

  20. My bedroom has french doors with a small window in the shower. The entire house has central air conditioning, but to save electricity costs, I prefer to cool my bedroom with a portable for a cooler sleeping space. If I vent into the closet or bathroom with the central air will the temperature really be too hot?

    • Hello Teresa, venting an AC into the closet is not a good idea. Venting a portable AC into the bathroom is an option; the temperature will increase there but your central AC can take care of that. However, if you use portable AC to create additional work for the central AC, you’re not really saving on electricity. Hope this helps.


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