Call us for a free quote 1300 13 40 41

How to install a window air conditioner?

Window air conditioning units are a simple, easy-to-install solution for keeping a room cool.  It is the simplest of the many direct expansion (DX) systems available.

By installing a window air conditioner you can save a lot of money.  If you’re only looking to cool a couple of rooms, something like a central air conditioning system may not be a suitable use of money and resources.

The best thing is that your window air conditioner unit should only take a matter of hours to install.  Also, when the summer heat is over, units may be easily removed for storage.

Similarly, when you move to a new house, you may be able to pack up and take the unit with you.  This is a great option in a rental property or for commercial tenants.

In the following article, we will present you with a guide for the correct installation of a window type air conditioner as well as outline their benefits.

What are the benefits of a window air conditioner?

Window air conditioners are still one of the most popular types of air conditioners out there.

For many people, these devices have become the only cooling system in their home or office.  But, what are window air conditioner benefits?


The smallest box unit models are the cheapest ones, while air conditioners with large cooling capacities can obviously cost a little more.  It depends on your needs but they can still be some of the cheapest air conditioner units on the market.

If you live in a rented home and you do not own the place, and the owner will not install any air conditioning for you, one solution is to install a room air conditioner (RAC).  This is logical as your investment is limited and it may not worth installing a more expensive air conditioning system.


Many units these days have variable digital controls instead of simple high and low settings.  Therefore it’s important for you to know how to choose an energy-efficient air conditioner.

Units with energy-saving switches provide further assistance in reducing utility costs.  Also, compared to whole-house ducted aircon, room air conditioners are very cost effective if you are only looking to cool one or two rooms.

Easy to buy

Window and room air conditioners are easy to find instore if you are planning to buy one.  Also, you can find them in online stores.  Buying them is as easy as a trip to the store or a few clicks online.

Easy installation

Unlike other cooling systems, such as central or large DX air conditioning systems, installation of window air conditioners is fairly straightforward.  Most people can do it without any prior experience or knowledge.  You don’t need a fully qualified air conditioning installer for this one!

Cleaning window air conditioner

How to install a window air conditioner?

Measure the room

Window air conditioning units come in various sizes and cooling capacities, so it is important to choose one that best suits the given room.  Firstly, check the measurement of the room.   This information will allow you to work out the area the unit will have to heat or cool.

If the room is unusually hot or cold, you can adjust the capacity (kW) of the unit accordingly.  Other factors that affect the performance of the window air conditioner are the number of people in the room and the size of the door/s to other rooms.  These are just some of the things to consider before buying a unit.

Once all factors have been considered, you can then work out what size air conditioner you need.  You can then move towards the fun part; buying a window air conditioning unit.

Choose a window

After choosing the room and AC size, you have to identify the window in your room where you want to install the window air conditioning unit.  Then measure the width of the window and the width of the air conditioner to ensure the unit will fit.  It’s wise to know the space available before buying the box unit!

If the window is too large, don’t worry too much because many window AC units come with an accordion-shaped panel to fill in the gap.  But if the window is too narrow, you will have to buy a smaller window unit or consider a through-the-wall install.

Keep in mind that window air conditioners come in two versions: one for double-sash windows and another for casement windows.  Some units are not interchangeable and you will have to make sure you have purchased the correct version for the type of window in which you want to install your air conditioner.

Check your window

Most units are designed to fit various types of windows. When choosing a window to place the air conditioner, keep safety in mind.

If you notice that your window frame is unstable, it is recommended to fix this problem first. Once everything is in order, you can proceed to place the window air conditioner.

Place the window unit

Once you have the window air conditioner ready, it’s time to install it.  Carefully remove all parts from the box and assemble the unit as directed in the instructions.

Most window air conditioners require you add additional components, such as flanges and accordion-style panels.  If your package comes with screws, use your screwdriver and insert them where needed.  If not, you will need to purchase them separately before starting the installation process.

Insert the air conditioner in the window

For this step, may need a friend or family member to help you because window air conditioners are heavy.  Open the window where you are going to install the unit.  If your air conditioner came with waterproof tape, run it along the windowsill.

Although these strips are optional, they help protect your unit from any damage that may occur during installation and removal.  They also prevent cold air from escaping.

With the help of your friend, lift and place the air conditioner on the bottom of the window frame.  While your helper holds the unit in position, proceed to the next step.

Adjust the window

Carefully adjust the window frame until it rests behind the top flange of the air conditioner. At the same time, make sure that the bottom flange fits well with the windowsill.

Install the angle brackets

Your unit should come with two angle brackets. These brackets are essential as they lock your window frames preventing the unit from falling.  To install the brackets, place one on each side of the top of the window frame that supports the air conditioner.

One of the angle brackets will usually fit into the inside slot of the window, while the other will rest on top of the window frame.  Put these brackets in place, using your screwdriver and the included or purchased screws.

If the wood is too hard, you may need to use a drill to create a starting hole and tighten the screws.

Old Window Air Conditioner

Seal the window gap

The last step in the window air conditioner installation process is to create a seal that blocks the gap between the upper and lower frames.

You can do this with an insulating foam strip.  Your window air conditioner kit should include one.  However, if it doesn’t, you will need to buy an insulating strip.

Push the strip where the bottom window frame meets the top one.  If the strip is too long, use a utility knife to cut it to the correct length.  Once the foam strip is snug, you are done installing your window air conditioner.

Now all you have to do is plug it in, turn it on, and enjoy.

If you have any questions, don’t hesitate to contact us!