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Does a Window Air Conditioner Have to Be in a Window?


With the scorching summer heat fast approaching, many of us turn to window air conditioners to keep ourselves and our houses cool and comfortable. As the name suggests, these AC units are designed to be installed in a window, but what if you own a small space and a windowless room, or you want to explore alternative options?

Here, we will explore whether you set up a window air conditioner without using a window and if there are other viable methods.

What is a Window Air Conditioner?

Window ACs have been a popular cooling solution for decades due to their cost-effectiveness and ease of placement in the house. They are designed to fit into standard-sized windows, with most units coming with remote control for ease of use, multiple fan modes for different temperature controls, and adjustable side panels to accommodate various window widths. 

When installed correctly, these units draw in heat from the room, cool it down, and then expel the heat and humidity outside. 

The advantage of the window aircon is that it allows for consistent heat exchange with the outside environment. Moreover, it doesn’t take up any floor area, making it ideal for smaller rooms or apartments.

Why Do Window Air Conditioners Need a Window?

The traditional placement of a window aircon on a window offers several compelling advantages, making it a popular and practical choice for many households:

Exhausting Hot Air

The primary function of a window aircon is to draw heat from the room and refreshen it. As the cooling process occurs, the AC generates warm air and humidity, which must be expelled outside for fast cooling. A window provides a convenient and reliable escape route for the air heat, ensuring it is released outdoors, away from the cooled area.

Ventilation and Airflow

Proper ventilation is essential for any air conditioning system’s effective operation. When a window AC is installed in a window, it creates a direct path for fresh outdoor air to enter the room. 

This continuous fresh air flow helps maintain the unit’s cooling efficiency, prevents the room from constant heat transfer, and ensures a steady oxygen supply for occupants. 

Moreover, an adequately ventilated room can stop the air conditioner from reusing its expelled air. Recycling exhaust air can result in a decline in cooling effectiveness and a decrease in indoor air quality.

Energy Efficiency

A window aircon operates more efficiently by venting warm air outside through a window. If the hot air remains trapped inside the room, the aircon would have to work harder to refresh the area, leading to increased energy consumption and reduced cooling efficiency. 

Proper ventilation through the window enables the aircon to chill the room more effectively with less energy, helping to save on electricity costs.

Condensation Drainage

As a window aircon chills the air, it also removes moisture from the indoor environment, resulting in condensation. The moisture must be drained properly to prevent water damage and avoid creating a humid environment conducive to mold growth. 

Many window aircon units have built-in mechanisms to channel the condensed water outside through the same window, ensuring working drainage. Wrong fixtures of window aircon without a window may cause your aircon damage.

Space Utilization

Installing a window aircon in a window offers a space-saving solution, particularly in smaller places or apartments with limited floor area. By utilizing the vertical area provided by the window frame, the window aircon does not occupy any valuable floor area, leaving the room uncluttered and allowing for a more flexible furniture arrangement.

Ease of Installment and Maintainance

Window units are designed with user convenience in mind. They are relatively easy to install. This user-friendly installing process allows for a hassle-free setup, and the ability to remove the aircon during colder months simplifies maintenance and storage.

While a window aircon is primarily designed to use a window, there are methods of putting up this type of AC. However, it’s important to consider that these alternatives may affect efficiency, ventilation, and overall performance. Hence, a proper installment method and adherence to manufacturer guidelines are essential to ensure optimal cooling and safe operation.

Does a Window AC Unit Have To Be Mounted to a Window?

Does a Window Air Conditioner Have to Be in a Window?

No, a window aircon does not necessarily have to be mounted to a window. A window AC can still operate and function normally even without a window. While the name suggests that it should be installed in a window, alternative methods exist for setting up a window aircon unit.

Convert Into a Portable Air Conditioner

Portable ACs are freestanding units designed to cool a room without a window mounting. Compared to window ACs, portable units can freely move around and have a unique ventilation method. 

Although inefficient, one of the best solutions to use a window air conditioner without a window is to utilize a window kit and modify your aircon into a portable unit. Portable ACs have an exhaust hose that must be vented outside through a partially open window, a specially designed vent hose kit, or a vent through the wall. 

To use a window air conditioner without a window, create a suitable inbuilt vent using your flexible duct and duct tape. Then, you must find a suitable passage of heat and water; you can use a window or a door to direct the heat outside your house. 

Afterward, you must secure your flexible duct with duct tape to regulate the temperature inside the room. Ensure that your vents properly drain outdoors to not flood your place. 

Several points stand out when considering the advantages of converting a window unit into a portable air conditioner. Firstly, its flexibility in placement and the ability to move quickly between different rooms make it a convenient cooling option. Moreover, its suitability for renters is noteworthy, as it doesn’t necessitate any permanent fixtures or alterations. Additionally, it can provide cooling without requiring modifications to windows is a notable benefit.

However, there are also some drawbacks associated with portable AC units. While they offer versatility, they are less efficient than window units. This discrepancy in efficiency is often due to the air leakage around the vent of a portable AC. Furthermore, an exhaust hose can raise aesthetic concerns, affecting the room’s overall appearance. Mitigating this issue might involve storing the hose and addressing the need for a nearby window or a designated vent hole.


A through-the-wall placement provides a more permanent and secure setup to use a window air conditioning system. Compared to a window AC, a through-the-wall placement is mounted on a hole in the wall. This placement is the best solution for using an air conditioner without a window. 

To achieve this, you create a hole in an exterior wall of your other room or any place in the house that is appropriately sized to accommodate the aircon. Then you must cut a hole for the ventilation tube through the wall of the other room or near the door. 

The window AC is inserted into the hole, and its mounting sleeve helps secure it. The ventilation tube can be placed in the hole near the door or window. This method is favored by those needing more suitable windows for traditional installations or who desire a more seamless, built-in look. 

This approach’s advantages include providing a durable and lasting cooling solution and the freedom to select the most suitable spot. Moreover, it avoids any hindrance to windows or interference with the entry of natural light.

However, there are some downsides to consider. The installation process demands greater involvement and specialized knowledge, and it might necessitate the assistance of professionals. This could lead to added costs for tasks such as creating the opening and fortifying the wall.

Mini-Split Air Conditioners

A mini-split aircon consists of two main components: an indoor aircon and an outdoor compressor connected by a small conduit. Compared to a window aircon, a split AC has an indoor aircon that can be mounted on a wall or ceiling.

This type of setup provides zoned cooling for specific areas of your house or other room places that do not require a window for fixtures. One of the ways to use a window aircon without a window is by converting your aircon into a mini-split aircon. 

Converting a portable AC into a mini-split AC presents several advantages. Zoned cooling becomes possible, enabling individualized comfort across various rooms. The stylish design of the indoor unit seamlessly integrates with interior aesthetics, and its independence from windows provides versatile possibilities.

However, there are also some drawbacks to consider. Professional assistance is essential due to the complexity of connecting refrigerant lines. As a result, initial setup expenses might be higher than choices. 

While these alternative methods offer flexibility, it’s important to note that window AC units are specifically designed for window installations. As such, an alternative setup’s ventilation and efficiency may have limitations or considerations. 

If you choose to put up a window aircon without a window, it’s essential to ensure proper airflow and follow manufacturer guidelines for safe and organized operation.

Can You Use a Window Air Conditioner Inside?

Yes, you can use a window unit aircon inside, but there are some important considerations to keep in mind.

Proper Ventilation

A window aircon uses the exhaust system to expel heat and humidity outside the door. When using a window unit as an indoor AC, you must ensure that the hot air is vented outside the door to maintain consistent cooling and prevent overheating of the unit. 

You can achieve this by providing a proper exhaust setup, such as using a window venting kit or attaching a hose to direct the hot air outside.

Ventilation Kit or Hose

Many window AC models come with a ventilation kit that allows you to vent the hot air through one room or another, a nearby window, or a specially designed opening. If your window AC does not include a venting kit, you may need to purchase one separately or create a custom solution using a flexible hose or duct.


A window aircon produces condensation as it cools the air. Ensuring an AC is properly drained is essential to prevent water damage or mold growth inside your living area. Some window AC units have a built-in drainage mechanism that directs moisture outside through the same venting kit used for hot air expulsion.

Noise and Vibration

Window AC units can generate noise and vibration during operation. Consider the noise levels and vibrations, especially if you plan to use the aircon in a bedroom or other quiet areas.

Window Sealing

Since window AC units are designed for window installations, you may need to ensure proper sealing around the aircon to prevent drafts and maintain cooling efficiency.

Safety Note: Always follow the manufacturer’s guidelines and instructions when using a window aircon. Be cautious not to block any air vents or the exhaust system to avoid overheating or causing damage to the unit. Consider seeking professional assistance if you need help with how to install an aircon or have any safety concerns.

While using a window aircon indoors is possible, it’s worth considering other types of air conditioners, such as portable or split-system units, which are specifically designed for indoor use and may offer more convenient options and additional features.

Final Thoughts

While a window aircon is traditionally designed for window installation, there are viable alternatives for cooling your living area. Through-the-wall installations, floor-standing ACs, and mini-split air conditioners can provide solutions for areas without suitable windows or those seeking more permanent and flexible setups.

However, it’s essential to consider factors like efficiency, airflow, and safety before choosing to DIY a window aircon setup.

JP Reyes

JP has been in the aircon industry for almost as long as he has been alive. As a child JP would help his tatay fix aircon units at their junk shop in Cavite. After graduating UP in the early 2000's, JP then started his own Aircon servicing business and within 5 years had 10 shops in 8 different cities. Fast forward to today and JP brings all his experience and expertise online to give readers trustworthy advice and reviews about Air-conditioning buying, servicing, cleaning and repair in the Philippines.

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