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Window AC- Have you installed it Right?

A Complete Guide on How to Install a Window AC Unit in Your Room



With summers around the corner, you must surely be looking for ways to beat the scorching heat.

If you are looking for a classic, affordable option to cool down your room, then a window air conditioner is an excellent choice. It is a reliable option that can cool a room of various sizes. Newer models make less noise and are more energy-efficient than those built a decade ago. You can also easily install a window AC without calling a professional, and this guide answers all your questions on how to install a window AC unit.


Quick Summary: This article will discuss all that you need to know when installing a window AC unit:

  • Things to consider before going for window AC installation

  • How to prepare for the window air conditioner installation?

  • How to install a window AC unit?

  • Dos and don’ts of installing a window air conditioner

  • How to make your window AC unit smart?

Things to Consider Before Installing a Window AC Unit


For finding the right window air conditioner, there are many factors to consider, such as the size of your room, the type of window you have, its orientation, energy efficiency rating of the AC, and how much insulation the unit will require.


1. Size of Your Room

Finding the perfect AC Size is important as a large unit will struggle to remove moisture from your room, while a small unit won’t cool properly on hot summer days.

To find the perfect size of window AC for your room, you first have to consider the cooling

capacity, which is measured in British Thermal Units (BTUs). Window air conditioners mostly come in 5,000 to 25,000 BTUs. You require 20 BTUs for every square footage of the area.

The first step is to measure your room’s size. Find out the width and length of your room, and then use this formula:

Length x Width = Area

To measure the area of a rectangular room, L-shaped room, or T-shaped room, you will first have to measure the shortest length and width of the room. Multiply them to get to the main area. Then calculate the area of the individual spaces in your room by measuring their length and width and multiplying them. Add all the areas to get the total area of your room.


2. Determine the Type of Your Window

Understanding the type of window you have is essential as window air conditioners are not designed to fit every window type.

If you have a sliding window or a casement that opens outwards, you can’t install a window air conditioner. A double-hung window in which there is an upper pane and lower pane that slides up and down is the most suitable for window air conditioners.


3. Energy Efficiency Rating of Your Window AC

For choosing the appropriate unit for your room, focusing on the right Energy Efficiency Rating is important. A higher EER number is always better. In the case of window air conditioners, the EER rating ranges from 8 to 12. A rating of 10 or higher is considered ideal for energy conservation.


4. Window Orientation

If you are installing a window AC unit in the south or west-facing window, then it would get direct sunlight for the most part of the day. A window AC, in that case, will not be able to handle the extra heat. Moreover, the intense direct light can decrease the efficiency of the unit by 10%

Consider installing your window AC in an east or north-facing window where it won’t get harsh sunlight.


5. Amount of Insulation

Insulation is essential to trap your cooled or heated air in your room and for protection against strong winds and rain when installing a window AC. If there are gaps around your window unit, air will escape, and outdoor air will enter the room, causing your AC to work harder and energy efficiency to decrease.


The amount of insulation required depends on the number of gaps. These can be identified by holding a candle and moving it around the AC; if the flame flickers, there is a gap. Insulation is also required in the spaces between the glass panes.


Your window AC may come with insulating foam; if not, you can easily get flexible foam for insulation.


Preparing For Your Window Air Conditioner Installation

Follow the guidelines below to prepare your window for a seamless installation process:


1. Clean & Inspect Your Window

Thoroughly inspect the window and make sure that it is in good condition. Check for rot or any other damages around the window frame. Your priority should be focusing on the necessary repairs. You would not want to find a problem after installing the unit.

It is also a good idea to properly clean the window as you won’t be cleaning it until after the end of the season.


2. Remove Obstructions Around the Window

If you have decorative items or plants on your window sill, it’s time to remove them. You will want to clear the area as much as you can so there are no obstructions when installing a window AC unit. If you have installed a storm window frame, it’s also time to remove it as it can interfere with the overhanging part of the unit.


3. Check the Load on the Circuit

Check the load on the circuit you want to use for your window AC unit. If the other devices are also plugged in the same circuit, there are chances of tripped breakers or a blown fuse, even with a simple appliance such as a hairdryer. A separate circuit that will solely power your window AC should be added.


How to Install a Window AC Unit?

After ensuring that you have checked all the points mentioned above, it’s time to install your window air conditioner!


Firstly, take your air conditioner out of the box, of course, and gather all the equipment that you may need, such as a screwdriver, screws, brackets, measuring tape, and scissors. Next, very important, call your assistant! You’ll need an extra pair of hands for the process. Also, don’t forget to read the user manual. You will want to make sure that you do everything according to your window AC installation guide.


Step 1: Mark the Center on the Window

Pull the bottom sash of your window as far as it can go. Next, measure the dimensions of the window and mark the center. Marking the center will ensure that the side panels evenly reach both sides of your window. Else the installed unit will appear uneven and unsymmetrical.


Step 2: Install the Weather Strip

If your AC manufacturer has provided a weatherstrip, install it to block incoming air that may protect your window from possible damage when you’re installing or removing the window AC unit.


Step 3: Attach the Side Panel to the Window Air Conditioner

Slide the side panels onto your air conditioner and fasten them using the provided screws. Ensure that you have tightened the screws and there are not any gaps to prevent warm air and pollutants from entering your home.


Step 4: Place Your AC in the Window

With the assistance of your helper, pick up your unit and insert it safely in the window. After that, close the window, making sure that the bottom window sash perfectly sits on the AC.


Step 5: Secure the Sash & Install L-Brackets

To prevent the window sash from being lifted accidentally, you need to secure it. Insert two screws through the upper AC case into the window sash. To prevent the wood from splitting up, drill pilot holes for screws going into your window frames.

Next, install L-brackets outdoors to hold the air conditioner in place. Use screws to attach the L-bracket to the upper window sash. This prevents the lower sash from accidentally opening.


Note: You cannot use L-brackets with all types of windows. If your window is a vinyl window, you can use wood strips to place between the sash and the top of the window frame.


Step 6: Fasten the Side Panels

In this step, you need to extend the side panels you initially installed with the air conditioner to the window sash track. After that, secure them in place with screws.


Step 7: Fill In the Gaps

Almost there! Use foam insulation to fill the gaps between the upper window sash and the lower window sash. If your AC comes with a foam strip, cut it and use it to fill the space; otherwise, you can buy it separately.


Dos & Don’ts of Window Air Conditioner Installation

When wondering how to install a window AC unit, you must also wonder if all the steps are necessary. In addition to the step-by-step guide, there are some tips and must-dos that you should follow when installing a window AC unit to get the job done quickly and securely.


Do Attach Panels and Rails for Support

To properly adjust your window unit in its place and prevent its fallout, use screws to attach the top and bottom mounting rails. After that, attach the side panels by sliding them along the grooves on either side of the unit. Make sure that panels fill in the gaps between the window unit and the sides of the window frame.


Do Install L-Brackets

A window air conditioner can be installed without additional support, but it would require additional support if it’s a large unit (more than 100 pounds). For support, you would need L brackets. They come in pairs and are L-shaped to hold the system securely in its place. These support brackets transfer some of the weight of the AC off the window sill. The L brackets also prevent the window from opening and causing the unit to fall, and minimize damage to the window. The latest versions in the market don’t even require any drilling.


Do Install Foam Seals

The gap between the two panes of the window needs to be filled to prevent drafts. If you don’t fill the gap, your unit will have to work harder to control the temperature and will fail to prevent moisture and dust accumulation in your room. You should fill it with a foam seal that usually comes with the window unit.


Do Take In Account the Tilt

Window air conditioners need a tilt so that the moisture accumulates in the drain pan rather than falling down inside your room. The tilt should be just half an inch but read the installation guide for the exact number. Some newer models don’t require the tilt as the drip pan is already installed at a slight angle.


Do Provide Sufficient Area for Airflow

Make sure that there are no shrubs, furniture, or walls obstructing the AC within 20 inches. If your window AC is suffocated, it won’t work effectively.


Don’t Try to Install On Your Own

A window unit is between 50-100 pounds, and installing it on your own can put your safety at risk. Even if you can carry it, securing it in its place with screws can be a challenge. So, it would best to install it with a helper.


Don’t Leave the Side Panels Unsecured

The side panels need to be firmly secured, so there is no issue with the air conditioner falling out of the window. You can do that by using the screws that come with your air conditioner package and drilling them in the side panels.


Don’t Forget to Check the Measurements

Your AC needs to fit your window properly and for that, taking measurements is essential. Measure the height and width of the window. Before going for AC shopping, measure the square footage of your room and then buy the system accordingly. The AC’s packaging specifies the maximum square footage it can cool/heat, so check it out.


Don’t Use an Extension Cord With Your Window AC

When installing a window AC, make sure there is an electrical outlet nearby. Do not use extension cords as there is a risk of fire, and it could also void your AC warranty.


Make Your Window AC Smart

After you are done with your window air conditioner installation, you will be looking for ways to maintain a perfect room temperature. Achieving the ideal settings manually can get quite difficult. That is why you need to make your window AC smart.

You can go for a smart AC controller that works with ductless mini-split, window, or portable AC. A smart controller can learn your desired temperature and humidity settings, set weekly schedules, keep you aware of your usage patterns, and be controlled from anywhere in the world using your phone.

In addition to automatically changing the settings according to your preferences, smart AC controllers can also help in reducing your energy usage and save up to 25% on your electricity bills!

Now that you know all about how to install a window AC unit, gather all your tools and start working. You will be enjoying a cool room in no time!


Be ready to enjoy your summer. To know more on HVAC, Visit: www.sbgblv.com



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