When it’s hot outside, a window air conditioner installation is worth the effort to help you keep your cool. Window air conditioners are an effective solution for keeping rooms cool without the expense of investing in a central air system.
Installing air conditioner window units is quick and easy. You can install a window air conditioner without enlisting professional help. While you can keep them in place year-round, you can also put them in place when the weather gets warm in the summer, and remove them when the air temperatures drop in the fall.
The following tips will make the process of installing a window air conditioner a breeze.
Choose the Right AC Unit
DIY window AC installation starts with finding a unit that matches the needs of the space. In order to evaluate the available energy output, find the BTU rating on the appliance.
BTU stands for British Thermal Units and acts as a measure of the air conditioner’s cooling capability. BTUs range from around 5,000 to 12,000. The lower the number, the smaller the space it will effectively cool.
Most window AC units will have the BTUs listed visibly on the box or website. Most also include an estimated square footage the air conditioner can be expected to cool.
To determine the space of your room, measure the length of one wall and multiply that length by the measurement you get for the width of the room. So a 10-foot by 12-foot room is 120 square feet. Similarly, a 20-foot by 17-foot living room will equal 340 square feet.
Ceiling height can make a difference in your square footage measurement. A basic eight-foot ceiling should be fine, but if you have taller ceilings, expect your AC requirements to be higher.
Similarly, if your room is open to other rooms, has a loft above it, or features large windows throughout, these factors will affect the efficiency of your unit. With this in mind, the basic square footage is just one factor in your calculation.
However, starting there, multiply the number you come up with times 25 to obtain the number of BTUs you’ll require. That 340-sq-ft room x 25 will require around 8,500 BTUs for efficient cooling.
Although BTUs may be the single most important factor in your decision, you’ll also want to consider which features are important to you. For example, if energy efficiency is a priority, look for the Energy Star rating. Units with a rating above nine will help you save on your utility costs.
Many of these units have added features like digital controls, sleep settings, and variable speeds that also help in conserving energy, plus offer convenience.
These conditioners may cost a little more, but they will be worth the expense over time.
Finally, consider whether you can even legally or contractually install window AC. If you rent, for example, your lease agreement may forbid installing air conditioner units in window openings of any kind.
In a basement or other area with small windows, an AC unit may block egress. Don’t let your cooling comfort cause a fire safety hazard by restricting your escape route.
Safety Note—Before beginning any type of window AC installation, make sure the power cord for the unit can reach a nearby outlet.
How to Install a Window AC Unit in a Double-hung Window
Before you begin the process of installing your window air conditioner, have a friend around to help you with the task.
These units can be cumbersome to handle and you will want an extra set of hands to prevent any chance of your new appliance falling and becoming damaged.
If your windows are double-hung, installing the unit will be quite easy.
You may need to organize the window extensions for the appliance if your model does not already have them installed. Other units have special window attachment supports. If your model has these brackets, position them before installing your unit.
Be sure to read the instructions provided by the manufacturer of your window air conditioner before you begin any work.
To start, lift the lower window pane. Position the unit onto the windowsill. Then slide the extension parts to block the extra window space.
Use the instructions to determine how to position the unit in the window. Most air conditioners sit somewhat to the outside so any condensation can drain away. However, there are some units that are designed to sit level in the window.
Attach the window air conditioner to the supports and lower the upper pane onto the appliance to secure it into position. Most units require you to ensure the upper pane is also secured so the air conditioner cannot move.
Lock the extensions into place.
An air conditioner will more effectively cool the space if you fill any gaps where warm air can enter or cool air can escape.
Use weather stripping to seal the unit into the inside of the window and fill any gaps between the unit and the window frame. Apply caulking to seal the outside of the window, if desired.
If your window has an odd shape, you may need to use a board to seal off any extra space that the extensions do not fill.
How to Install a Window Air Conditioner in a Sliding Window
Again, start by recruiting a friend to help. Open the window and lift the unit into place. Window air conditioning units are really meant for double-hung windows. You can skirt this possible obstacle by cutting a board to fill the space above the air conditioning unit.
Never install a window air conditioner vertically, thinking it will make better use of space. You can damage the unit by doing this.
Carefully measure the opening. Then use those measurements to precisely cut a piece of plywood to size. Fit it into place with the unit below it.
A huge piece of plywood is an eyesore and blocks your view out the window. If this is a problem for you, you can build a basic frame for a piece of plexiglass. Once in place, the unit will allow light to filter through while still filling the gap.
With your AC window unit and plywood in place, close the sliding window as far as you can. Then wedge the window into place with a block of wood in the runner to keep it from opening.
Window AC Installation for a Casement Window
Each type of window installation is slightly different, but they all begin with asking for help. This is a job best performed by two people, especially with larger window AC units.
When shopping for your AC unit, ensure it will fit in the opening for your casement window (also known as a crank window).
You’ll need to remove the inside and outside windows in order to allow space for your window AC installation.
Like other types of installation, a casement window air conditioner installation requires you to lift the AC unit into place.
The groove on the bottom of the unit matches the groove in the window. This is the first layer of support to keep the unit from falling out of the window.
Ensure your unit is sitting at the proper slope to allow condensation to run out the back. This slope will be outlined in the directions for your unit, but often matches the slope of the window sill on the outside of the window.
Since casement windows aren’t the standard type for DIY window AC installation, you may want to modify the accordion pieces that come with most units. Replace them with a strip of wood instead.
Cut the wood to size, depending on the width of your opening on either side of the unit. It may need to be thin, like one inch, or wider, like six inches. Either way, mount the piece to the sides of the AC unit where there are already screw holes for the accordion.
This wood will sit inside the window frame to further restrict the AC unit from tilting out the window.
If you don’t have a natural ledge on the inside of the frame, mount a board to the inside of the window frame with screws.
The board attached to your AC unit will then lean against the board mounted into the frame. Just make sure these boards have the same backward-tilting angle as the drainage requirements for the unit.
At this point, you can install a top board or plexiglass to fill the space of the missing window.
With any of these window AC installations, you can also rely on brackets to support the unit. These brackets are mounted to the outside of the house, directly below the air conditioning unit. Most units have screw holes for this purpose and many include the brackets in the installation kit.
Power Your AC Unit
With the installation complete, plug your unit in and ensure everything works properly.
Window air conditioners can consume a great deal of energy, so be sure to connect them to a circuit that will have enough power.
If the circuit you are using is also providing power to other appliances that need high levels of energy, you could have a problem, such as a circuit breaker that continuously flips when the unit kicks on or after it runs for a while.
If you need an extension cord to reach an outlet, use the shortest cord possible.
Maintain Your AC Unit
Regardless of the type of AC unit you decide on, there will be some maintenance to perform. Smaller AC units last an average of 10 years, with proper care, so it’s worth making sure they are well maintained.
If your unit seems to be struggling for any reason, start by ensuring the angle for the condensation release is correct. Water collecting in the bottom of the unit will cause poor performance and inefficiencies.
Most AC units have filters that need to be cleaned or replaced regularly. Some units have more than one. Know how to access and care for the filters. It’s the fundamental component of good AC care.
Check out this information for a more comprehensive look at How to Service and Maintain Your Air Conditioner.
Removing Your Air Conditioner
If your unit is properly sealed into the window, you should be able to leave it installed all year. If you do leave it in place, check out How to Protect a Window-Mounted Air Conditioner.
However, if you live in a climate with a short hot-weather season, there’s no need to block your views and the natural air flow with a unit you won’t be using for months on end.
If you would like access to your window space later in the year, you can easily remove your window air conditioner and store it away.
Just like during installation, you will likely need a helping hand for this job. However, it’s not a difficult task. Simply perform the installation procedure in reverse.
Remove any extensions, plywood, plexiglass, or other reinforcements and gap fillers. Open the window, if there is one. Unplug the air conditioner.
If you plan to bring the window air conditioner through the inside of the window, be sure to tilt it backward first in order to drain any water that may be inside. Otherwise, you’ll have a mess to deal with.
Then detach the unit from the window groove and remove it from the window space. Be careful to keep all of the hardware contained.
Label boards, so you remember which window they fit into when it’s time to put the window AC back in place next season.
Store the unit in a dry and protected space to reduce any chances of damage from moisture or debris.
Choosing, buying, installing, maintaining, and removing a window air conditioner isn’t a difficult task, and is one with a very cool reward.
If you’re considering another kind of air conditioning system, check out The Four Types of Air Conditioners. Also, if it’s a problem for you, you might want to investigate How to Remove Bad Odors From an Air Conditioner.