How To Install a Window Air Conditioner

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A window air conditioner was made to be a plug and play appliance that will give you that cool feeling without having to drill holes in your wall. One of the features that make window air conditioners a popular choice is that most models fit in standard double-hung windows.

A window air conditioner is the ideal model type for apartments, condominium units, and rented housing where reconstruction of the home is not allowed. It is relatively easy to install a window air conditioner even without professional help, and you simply plug in the unit to start using it.

How to Install Window Air Conditioner: The Installation Process

Learn the step-by-step process of installing a window AC unit in our handy guide. However, if you are not confident with your shop skills, as installation will require some drilling, we suggest you hire a professional AC technician or contractor to install the unit for you.

Step 1: Size Your Window

First thing's first: measure the size of your window. Take a roll of measuring tape and take note of the inner area of your window for a precise fit of your new window air conditioner. It is important to measure the window opening excluding the frame for a guide on purchasing a suitably-sized window unit.

You should also take note of the size of your room in sqm. This will help you figure out which model has the best cooling capacity for the size of your room. Make sure to measure the area of any adjacent rooms as well if you plan to cool down more than one room at a time.

Step 2: Choose Your Unit

Next, choose your unit. There are plenty of modern models available that may range from being eco-friendly and eco-savers, to high-powered models for large rooms. Some units may also come with built-in air purifiers. Choose a window air conditioning unit depending on your preferred brand, model, and budget.

This is where your measurements come in handy. Talk to a trusted provider to find the right window air conditioner model for you based on the size of your window, and the area of your room. Make sure the model you purchase is sufficient enough for your room.

Step 3: Read the Manufacturer's Instructions

Before installing a window AC unit, be sure to read the manufacturer's instructions for notes, and familiarize yourself with the set of tools and materials you need. Check to see what kind of screws you should use, and for tips and tricks on mounting your specific air conditioner model. Check for the power voltage as well so you can make adjustments to the power outlet.

If you have sliding windows, keep the windows open all the way up as far as it can go. Have a helper or assistant with you as you mount the AC unit, as these tend to be too heavy for one person to carry and install at the same time. Most units come with an installation kit which includes the nails and screws needed to install a window air conditioner.

Step 4: Mount the Steel Support Bracket

Go outside and mount the steel support bracket just below the window frame. This will support your AC unit as the appliance tends to get heavy. If you live in an apartment or condominium unit, this will prevent any accidents with your unit. Drill the bracket into the outside of your window accordingly.

Pro tip: you would want to mount your air conditioner at a slight angle facing downward towards the outside of your window for the condensation to drop outside instead of inside your home. Measure out where you would want to place the brackets, and mark the drill areas with a washable marker.

Step 5: Center the Air Conditioner on the Windowsill

Most window-type air conditioners come with accordion style side panels that are adjustable to varying window sizes. Center your air conditioner until the panels evenly reach the window frame. Adjust the window sash as far as it can go, and keep the power cord out of the way as you do so.

Adjust the accordion side panels to tightly fit the unit into your window, and add foam insulation to keep the seal air tight around the panels and the lower window sash. Foam insulation will keep the cool air in, and the hot air out of your room.

Step 6: Set the Bracket, and Drill Pilot Holes

Find the middle drilling hole on the upper sash of the unit. This is where you will attach the window AC to the window itself. Align the drill hole to the middle of the window. There should be a small hole in your window frame as well to serve as a guide. Drill a screw in to keep the unit in place.

Find any other drill spots, and affix the unit onto the window. This is also the step where you can check the position of the steel brackets, and adjust accordingly to fit your unit. The brackets should act as a support system for the heavy machine.

Step 7: Secure the Window Air Conditioner Unit

Lastly, secure the unit to complete the installation. Use a power drill to securely tighten the screws onto the unit and the window frames. Make sure everything is secure before plugging in your device, and enjoy the cooling capacities of your newly-installed window air conditioner!


1. Can I install a window air conditioner without brackets?

The short answer is yes. You can install a window air conditioner without having to install steel brackets. However, these brackets are mainly there as a support system for the otherwise heavy appliance, and will greatly prevent damages in case the screws holding the unit in place are loose or not secured properly.

2. How can I install a window air conditioner without a window?

You will need to measure the exact size of your air conditioning unit, and cut out a section of your wall where you want to place the unit. This will require some construction know-how, and is not applicable for rented spaces where restrictions may apply.

3. What capacity room air conditioner should I get for the area of my room?

Refer to this chart for the recommended air conditioner capacity relative to your room size:

4. I don't have a power outlet near my window, can I still install a window air conditioner?

You can power your AC unit with an extension cord attached to a main power outlet. Make sure you do not overload the circuits by plugging in too many devices on one extension cord, and be sure the connection is stable by mounting the extension cord on the wall near your window.

DIY Video Tutorials

Try your hand at installing your new window AC. Here are some helpful videos on how to install a window-type air conditioner with step-by-step instructions so you can have a visual on the proper installation of your unit:

Keep Your Cool

Inexperienced homeowners may feel frustrated at installing any type of air conditioning system, which is why we at Luce Aircon offer our installation, maintenance, and aircon cleaning services at your convenience! Check out the rest of our aircon services today for more information.

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