How To Vent a Window Air Conditioner Without a Window to Stay Cool Year-Round

Josh Miller

Josh is a contributing writer to the site and former HVAC specialist.

Last Updated on January 21, 2022

All air conditioners need to vent so they can work. An air conditioner works by sucking warm air out of your room, cooling it, and then returning it to your room, but it also emits warm exhaust in the process. If there’s nowhere for that warm exhaust to go, it’s pumped right back into your room.

Many believe that you need a window to vent your window AC unit, but there are other ways to do it when a window isn’t an option. You can vent window air conditioners through a sliding French door, an interior or exterior wall, or a ceiling; there are a variety of choices.

How to Vent a Portable Air Conditioner Without a Window to Stay Cool Year-Round
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Table of Contents

Supplies You’ll Need to Make a Vent

The tools required for making a vent will vary depending on the method you choose. If you’re comfortable with power tools, creating a wall vent is a viable option for you. However, wall vents create a permanent hole in your wall unless you take advantage of an existing opening like an old dryer vent.

You will also need more specialized tools if you have to cut through brick or another material for the exterior walls. If you prefer to create a less-permanent interior vent or use a pet flap, you may accomplish your goal with just a piece of hose and a utility knife. With some duct tape, caulk, or another material for sealing the gaps around the vent, you can create a well-sealed basic vent in under an hour.

Vent the Air Conditioner Through a Door

When figuring out how to vent a window air conditioner without a window, it’s always easiest to utilize other existing openings. Sliding doors are the easiest options, as there are specific kits you can buy for window air conditioning units to fit it into a sliding door. These kits keep the door ajar but seal off the areas above and below the hose opening.

Every room has to have a doorway, even when it only has a limited number of windows. Even an interior doorway might be an option for venting if you extend the hose long enough to ensure the heat isn’t being vented directly outside the door.

You can secure the hose along the wall and door frame to reduce the risk of a trip hazard and either cut a small gap in the door itself or leave the door ajar during use. However, this method isn’t aesthetically pleasing, and modifying the door could get you in trouble if you’re leasing the property.

Vent it Through a Wall

Venting window air conditioning units through the wall can be easy if working through an interior wall, but it’s much more difficult if you have to go through an exterior wall. Although this also won’t be an option if you’re leasing the property, it’s an option for homeowners trying to make window AC work for them long-term.

To cut a vent through the interior walls of a home doesn’t take much effort. However, this simply dumps the warm exhaust in another room, which will make that room less comfortable for its occupants. If you are trying to cool a bedroom or another vital living space while the rest of the house is unoccupied, this can be a viable option.

Use a stud finder with the ability to check for electrical wires. You’ll want to avoid both wall studs and wires while cutting through the wall. Once you have a clear path, it’s easy to cut through both sides of the drywall with a round saw that fits on the end of a drill.

Exterior walls require specialized power tools that you might not have on hand. Low-density concrete is the easiest to cut through, but even this will require time and care. Like with interior walls, you’ll have to be careful not to damage any utility lines.

You will need to seal the gaps around the hose with caulk or another form of sealant for both interior and exterior walls. If you accidentally make the hole noticeably too large for the hose, try wrapping the hose with duct tape to help wedge it into the hole more securely.

Vent it Through an Existing Vent or Flap

A ready-made vent has already been professionally installed if you have an in-house washer and dryer. If you’re lucky enough to have a dryer vent nearby, you can vent your window air conditioner through that.

You can also vent an AC unit through a pet door built into an interior or exterior door. Like with other ventilation methods, you’ll need to seal up any remaining gaps, especially since pet doors aren’t meant for small, round hoses. It may help to create your own plastic flap with a large circular hole in it that you can snap into place while using the AC.

Vent it Through the Ceiling

It’s tough to decide how to vent a window air conditioner without a window if the door isn’t an option and you don’t want to cut a hole in a wall. Venting through the ceiling is a better option than it appears at first glance because heat rises.

This usually only works with drop ceilings since they have enough space for ventilation. It’s easiest to install in tiled ceilings, so this is an excellent choice for AC units in offices. You might also be able to use it in sunrooms or other add-ons to your home that have suitable ceiling space.

Remaining Flexible

If you’re relying on a window AC unit for cooling, chances are you’re in an older home, or you’re dealing with temporary heat. Keep in mind that you may want to avoid permanently altering walls or doors, especially if you plan on upgrading to central air or even a ductless mini split in the near future.

However, it’s well worth investing some time and money into venting if it improves your quality of life. When done right, venting your AC unit properly can make it more energy-efficient and keep you from wasting money. Use doors, walls, and vents in the room to your advantage to keep you and your family cool year-round. 

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