How to Vent a Portable Air Conditioner Without a Window

If you want to vent a portable air conditioner without a window, you have options.

Here’s how to vent a portable air conditioner without a window:

A portable air conditioner without a window still has to send its hot exhaust outdoors. The options makers support are a sliding door kit or a vent through an exterior wall. Some makers also allow a drop ceiling kit or a dryer-style wall vent of the right size. Do not vent into a floor register, attic, crawlspace, chimney or another room.

This guide covers which methods makers support and which to avoid.

Every Portable Air Conditioner Needs a Path Outdoors

A portable air conditioner moves heat and moisture out of the room through its exhaust hose. GE Appliances says the appliance will not remove heat and humidity from the room without an exhaust vent, and that it must be vented outdoors, not into an attic or other indoor space. A unit sold as ventless is normally an evaporative cooler, which works differently: the US Department of Energy says those add humidity and only suit areas with low humidity.

Makers also limit how far the exhaust hose can run. Place the unit close to the outlet and keep the hose as short and straight as the manual allows. GE supplies a 5 foot hose and De’Longhi says its supplied hose is about 4 feet long.

Do Not Vent Into a Floor Register

A floor register is part of the heating and cooling ductwork of the home. It does not lead outdoors. Exhaust pushed into it stays inside the building, along with the moisture it carries, and can be carried to other rooms. De’Longhi warns that the hot air from the unit contains moisture that will produce mold if it is vented internally.

Sliding Door Kit

Another option is to use a sliding door kit.

• A sliding door kit is an effective solution for venting a portable air conditioner without a window.
• This kit allows you to create an opening in your sliding glass door, providing an outlet for the hot air expelled by the AC unit.

The process involves installing a panel into the track of your sliding door, which seals off the gap left when the door is opened.

The panel includes a hole that can be connected to the exhaust hose of your portable AC unit using the adapter supplied with the kit. By attaching the hose through this panel, you can easily vent out hot air from your room.

These kits are usually adjustable within a set height range and are often sold separately from the air conditioner, so measure the door opening before buying. They offer a convenient and temporary solution that doesn’t require any permanent modifications to your property. However, it’s important to make sure that you properly seal any gaps around the installed panel with weatherstripping or insulation to prevent drafts and maintain energy efficiency in your space.

Venting through a Wall

Venting your portable air conditioner through a wall is an effective solution for cooling a room without windows.

Here is what makers say about it:

1. Through an Exterior Wall:The hose must pass through a wall that faces outdoors, not a wall shared with another room, a garage or a hallway. This means cutting a hole and fitting a wall vent, which is a permanent change to the building. Whynter says wall installation is possible but requires some modification. Use the adapter and hole size given in the manual, and keep the hose within the length the maker allows.

Remember, before proceeding with any method, always check local building codes and regulations regarding ventilation installations.

Venting through a Drop Ceiling

A drop ceiling is an option that some makers accept and others advise against. Whynter lists drop ceiling panels as an alternative to a window. GE Appliances does not recommend venting upward through a ceiling and says the exhaust must go outdoors. The space above a drop ceiling is still inside the building, so the heat and moisture stay there unless that space is itself ventilated to the outdoors. Check the manual, and ask the building owner or manager before using this method in an office or rental.

Here’s how you can make it work:

1. Find the ideal location: Locate an area in the room where you want to position your portable air conditioner. Ensure that there is enough space for proper airflow and easy maintenance.
2. Prepare the venting materials: Use a drop ceiling kit made or approved by the maker of the air conditioner. Do not add extra ducting to reach the ceiling unless the manual allows it, because most makers advise against extending the hose.
3. Make necessary adjustments: Fit the ceiling panel from the kit in place of one tile, above the unit.
4. Connect and secure everything: Connect the hose to the ceiling panel adapter and to the unit as the kit instructions describe. Keep the hose as straight as possible. GE advises against bending it more than 45 degrees.
5. Test it out: Turn on your air conditioner and check that warm exhaust air is leaving through the hose with no obstructions or leaks, and that cool air is coming from the front of the unit.

Venting through a drop ceiling offers a discreet solution by hiding both the exhaust hose and installation hardware from plain sight, maintaining aesthetics within your living environment but it only works well when the space above the ceiling can release the heat and moisture outdoors.

Using a Dryer-Style Wall Vent

A dryer-style vent hood on an exterior wall can work as the outlet for a portable air conditioner, but only under the conditions the maker sets. GE Appliances accepts a dryer vent or similar outlet as long as the opening has a 5 inch diameter. Whynter lists dryer vent exhaust as an option only if compatible.

A standard clothes dryer duct is about 4 inches in diameter, which is smaller than the 5.9 inch hose GE supplies with its units. Forcing the exhaust through a narrower duct restricts airflow.

Do not share a duct with a clothes dryer. Dryer ducts collect lint, which is flammable, and a dryer needs its own clear exhaust path.

Check the air conditioner manual before using any outlet other than the supplied window kit, and ask the maker if the manual does not cover it.

Why a Chimney Is Not a Safe Vent Path

None of the maker instructions checked for this article lists a chimney as a vent path. A flue that serves a fireplace, wood stove, furnace or water heater has to stay clear. The EPA warns that blocked chimneys or flues release harmful combustion gases and even fatal concentrations of carbon monoxide. Do not fit an exhaust hose into any flue that serves a fuel-burning appliance.

Homes with any fuel-burning appliance should have working carbon monoxide alarms. The CPSC says to install them on every level of the home and outside sleeping areas.

Do Not Vent Into an Attic or Crawlspace

Venting a portable air conditioner into an attic or crawlspace is not a supported method. GE Appliances states that the unit must be vented outdoors and not into an attic or other indoor space. The exhaust carries heat and moisture, which can build up in an enclosed space and encourage mold.

The only acceptable route through an attic or crawlspace is one where the exhaust continues to an outlet on the outside of the building. That usually exceeds the hose length makers allow, so it is a job for a licensed HVAC contractor and not a hose extension.

Venting a Portable AC Unit in Non-Traditional Settings

If you don’t have access to a window, there are still several options available for venting your portable AC unit.

Here are some alternative solutions:

1. Vent through a sliding glass door: Some portable air conditioners come with an adjustable kit that allows you to install the exhaust hose through a sliding glass door. This provides a secure and efficient way to vent the hot air outside without damaging the door or compromising security.
2. Vent through a drop ceiling: If you have a drop ceiling in your space, you can use it as an alternative venting option. Some makers offer a drop ceiling kit for this. Others advise against venting upward through a ceiling, so check the manual first.

Remember that proper ventilation is crucial for maintaining optimal performance and efficiency of your portable air conditioner.

Make sure to follow manufacturer guidelines and consult professionals if needed when exploring non-traditional ways of venting.

Here is a video about how to vent a portable air conditioner without a window:

Tips and Tricks for Efficiently Venting a Portable AC Unit

1. Use a sliding glass door: If you do not have access to a window, utilizing a sliding glass door can provide an effective venting solution. Simply install an adjustable panel kit specifically designed for this purpose, ensuring proper insulation between the door and the panel to prevent hot air infiltration.
2. Keep to the supplied hose:Makers advise against replacing or lengthening the exhaust hose. GE does not recommend extending it past 5 feet, and De’Longhi says lengthening it can damage the product. If the supplied hose cannot reach an outdoor outlet, move the unit or choose a different cooling option.
3. Optimize placement of the unit: Position your portable AC unit as close as possible to an exterior wall or doorway for efficient venting. This minimizes the length of ductwork required and reduces energy loss during air transfer.
4. Consider adding additional insulation: To further improve efficiency, apply weatherstripping or insulating foam around any gaps where warm air could leak back into your space after being expelled by the portable AC unit.
5. Regular maintenance is key: Be sure to clean and replace filters regularly as clogged filters hinder airflow and reduce cooling performance. Additionally, inspect all connections and seals periodically to minimize any leakage that may impede efficient venting.
6. Limit bends in the hose: GE Appliances advises against bending the hose more than 45 degrees. Whynter says not to exceed 9 feet in total hose length and to avoid sharp bends or vertical lifts.

By following these tips and tricks, a portable AC unit can be vented outdoors even without a standard window.

Final Thoughts: How to Vent a Portable Air Conditioner Without a Window

There is much more to portable air conditioners than venting them.

Browse the related guides on portable air conditioners and other cooling gadgets below.

Read This Next

• A Guide to Portable Evaporative Coolers
• Are Hessaire Portable Evaporative Coolers Good?
• Does Portable Evaporative Cooling Work?
• Tips to Make a Portable Air Conditioner Colder

Sources

GE Appliances (exhaust vent hose)
GE Appliances (extending exhaust hoses)
Whynter (FAQs)
De’Longhi (venting a portable air conditioner)
De’Longhi (extending the hose)
EPA (sources of combustion products)
CPSC (carbon monoxide questions and answers)
US Department of Energy (evaporative coolers)

Reviewed October 2026. We changed the ventless kit, floor vent, chimney and attic sections into warnings, removed the PVC pipe and plumbing drain methods, which makers do not support, and corrected the drop ceiling, dryer vent and hose length advice using GE, Whynter and De’Longhi guidance and EPA and CPSC safety information.