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How to Vent a Portable Air Conditioner Without a Window

How to Vent a Portable Air Conditioner Without a Window

Portable air conditioners are a great solution to bring air conditioning to isolated rooms without running permanent ductwork as you would for central heating and cooling.

They’re small portable units that need a power plug and an opening to the outside to vent hot air, and they are good to go. The most common and convenient way to vent portable air conditioners is by bypassing the vent tube through a nearby window.

Why Do You Have to Vent your Portable Air Conditioner?

When the portable AC extracts hot air from the room, it needs to vent it outside. Otherwise, it will heat the room it’s trying to cool again.

How Do Portable Air Conditioners Work Without a Window?

Finding a way to guide the hot air generated as the unit cools a room to the exterior is the basis of venting your portable unit. It doesn’t matter how you choose to channel the air to the outside. Any alternative approach that opens the exhaust vent to the outside will work just perfectly.

Venting a Portable Air Conditioners Without a Window: Best Ideas

While the options might be endless and varied depending on your home’s design, people opt for a couple of universal venting options when they can’t access a window.

Venting Your Portable Air Conditioner Through a Wall

If you install the unit with access to the outside through a wall, you can drill a wall through the wall and pass the exhaust vent out. You can also use this approach to vent into another room with access to the outside that won’t mind the heat.

For instance, you can vent to an adjacent laundry room, storage area, or garage. This could be a great way to heat an adjoining room while using the fans and windows in that room to get excess heat out.

How to Vent a Portable Air Conditioner Through a Wall

You will need to drill a hole through the wall, pass the tube through, and weatherproof the hole.

ProTip: While you can DIY the adapter and flushing to make the installation weatherproof and neat, using a custom wall mount kit compatible with your exhaust tube size will make installation faster and easier

Use a drill with the correct hole cutting bit (or a drywall saw) to cut a hole that is just big enough to accommodate the provided exhaust vent.

  • The way you cut the hole will vary depending on what your wall is made of
  • Make the hole half an inch bigger than the exhaust vent
  • If you chose a wall mount kit, use the recommended hole sizes for a perfect fit
  • If you are using a DIY kit, skip to the next section to see a DIY kit idea
  • Otherwise, insert the interior flange onto the exhaust tube before passing it through the hole you just drilled
  • On the outside, attach it to the exterior vent cover and screw the vent cover onto the wall
  • Go back to the inside and mount the interior flange flush to the wall

If you decide to skip the wall mount kit, you can secure your vent using some silicone and vents. You can even repurpose the window vent kit most portable air conditioners to get the job done.

Use a piece of plastic or wood to fashion a neat circular interior trim to aesthetically seal around the point where the vent goes into the wall in the house

Alternatively, you can trim the window mounting kit to size (even though letting it be is a good idea, you might need it when you move the unit to a room with a window)

  • Drill the vent hole to about half an inch bigger than the exhaust vent tube
  • Insert your indoor trim of choice to the pipe before the next step
  • Pass the exhaust vent  through the hole until it is flush with the exterior of the hole
  • On the outside, spray some silicone (or any expanding glue of choice) between the tube and the wall to seal the hole and hold it in place
  • use a regular outdoors vent cover to protect the tube
  • On the inside, use the silicone or glue again before mounting your trim of choice

You can use a 3D printer to print your own custom flashing for both sides.

On the inside, you can make do without any trim if you drill the hole behind the portable air conditioner unit and use it to hide the hole.

Venting Through the Ceiling

If your only access to the outside is through the roof, there is no problem with venting your portable air conditioning unit through the ceiling into the crawlspace.

After all, the crawlspace is well ventilated and mostly never used.

In this case, all you have to do is drill a fitting hole onto the ideal spot on the ceiling, passing the vent through and using silicon or caulk to seal it in place.

Again, you can 3D print a custom flashing or use a wall mounting kit flashing to make the installation prettier and professional.

There’s no need to drill through to the roof. The ventilation in your crawlspace should be sufficient to shuttle away from the heat. Moreover, drilling through the roof makes your home susceptible to leaks.

Venting Through a Sliding Door

If you think of it, sliding doors aren’t that much different from your sliding windows. They’re just bigger and heavier.

Extending the window installation kit could let you vent your portable AC unit through the door.

You will need some skill bending soft sheet metal like aluminum to secure the installation, especially on a door to the outside. You will also need to extend the locking mechanism and ensure the door still locks with the vent in place.

After all, you don’t want people waltzing in through your otherwise unlocked door.

Venting Through a Dryer Vent

The final option would be passing your vent through a dryer vent. While this hack works for some homeowners, manufacturers and technicians are against it.

To begin with, the portable air conditioner vent is bigger than what your dryer has. This means even if you don’t use the two units at a go, you won’t have enough diameter and airflow to efficiently vent your portable unit and keep it working at its best.

What Happens If You Don’t Vent a Portable Air Conditioner?

If you don’t vent a portable air conditioner, it will keep running hard but won’t cool the room as much. It will be blowing cold air, but at the same time, it will be dumping all the heat it’s getting out of the air back into the room, heating it.

The room will eventually be warmer than it would have been if you simply turned the unit off, as it will also be generating additional heat as it runs.

Can You Vent a Portable Air conditioner Through a Screen?

Window screens let air through. They won’t affect your portable air conditioner venting in any way. As such, you don’t have to extend the vent beyond the screen. Just install the window mounting kit, and you are good to go.

How Long Can the Exhaust Hose Be on a Portable Air Conditioner?

Your exhaust hose length varies depending on the model of the AC unit you are dealing with. Most dimensions range between four and seven feet.

This is more than enough to get to the window or wall for mainstream venting. If you need more length to get to the ceiling or an appropriate venting space, go for units with a longer exhaust hose.

Check this too: How to Clean a Window Air Conditioner

If your current unit doesn’t have a long enough vent, refrain from extending it. Manufacturers accommodate for the length when designing equipment efficiency. Some will even void the warranty if you cut and open the vent.

Short Exhaust Vent Workaround

If you must extent your exhaust vent, you can use a workaround by venting into an actively ventilated opening.

Here is my take on this

  • Install the exhaust vent so that it opens into an adjacent room with access to the outside
  • Install a fan to the adjoining room to improve airflow and get rid of the heat faster
  • If you don’t have an adjacent room, you can build a two sq. ft box to vent into, then install a fan and ductwork to pull the hot out of the box using ductwork and an exhaust fan to the outside
  • Don’t make the box sealed as this could pass suction pressure through the portable air conditioner’s exhaust vent into the unit, ruining it

Leave some ventilation slats so that the AC unit ‘feels’ like it’s venting into an open space. The additional exhaust fan will pull any extra air in through the ventilation slots in the box and won’t try to suck air through the AC exhaust vent

Bottom Line

Venting your portable air conditioner should be easy as long as you know what it is all about. A creative mind will have no problem passing all that hot air to the outside of the house.