When summer is knocking on your door and you know unbearable heat waves are coming you should start to think about a purchase of an air conditioner. On the market, there are many efficient units such as window air conditioners, portable air conditioner or wall-in air units. You can also rely on the central AC machine if it’s possible to install it regarding the layout of your house and if it’s not too expensive for you. The perfect solution for your bank account and your requirements is to choose a window AC unit. But what is the right size window air conditioner?
The vast majority underestimate the first question and make a mistake in choosing the new machine. Don’t be like them and do your best to pick the best one. Then, you can be sure about preventing skyrocket energy bills for operating the device. And you won’t struggle with a unit that isn’t able to properly cool down your room.
Underestimating a problem of the right size window air conditioner can result in buying an incorrect unit. It means you can face two possible issues. The first one occurs when you buy a machine that is stronger than you need. Your energy bills will skyrocket. The cause is the big unit will consume lots of energy however it’s not required regarding the size of the room. The second issue usually happens if you buy a not so powerful unit to cool down your room. A required temperature can’t be reached with a weak machine and you never reach the optimal comfort.
To obtain the right size window air conditioner you need to find out some parameters that are crucial for your purchase. Let’s take a closer look at all of them together.
Measure the Room
The first parameter we need to focus on is the square footage (sq. ft.) of a room you desire to buy a window AC unit for. It’s very easy to measure your room and it doesn’t matter what shape it has.
Square Room
Measure the width of the room in feet. Multiply the numbers.
- Example: 30 feet x 30 feet = 900 sq. ft.
Rectangular Room
Measure the width and length of the room. Multiply these two numbers.
- Example: 30 feet x 20 feet = 600 sq. ft.
Triangular Room
Measure the width and length and multiply these two numbers. Then, divide them in half.
- Example: 30 feet x 10 feet = 300 sq. ft. , and 300 ÷ 2 = 150 sq. ft.
Unusual Shape of Room
Try to break your room into small triangles and rectangles. Find out the square footage of all pieces and get them together. The final number use as a parameter in square footage.
Once, we have our first important parameter of room measurement in square footage we can move on to the next part of a guide on how to find the right size window air conditioner. Or if you know that you have a large room you can check my detailed guide for how to choose the best window air conditioners for a large room.
Find out the Proper BTU
People usually don’t want to waste time and skip this parameter. But we have to point out how crucial it is. If you want to buy a very good unit focus on the BTU.
The BTU is the British Thermal Unit and represents how much energy you need to cool down the room. The best way how to find the BTU appropriate for your room is to compare the measurement of a room with an appropriate BTU in a table. The smaller room needs a smaller BTU ratio and a bigger room needs a higher BTU.
A simple table below gives a great overview of how to match your square footage with a proper BTU value. Once, you find the BTU ratio for your room you have another parameter you have been looking for.
| Area of Your Room (in Square Feet) | A Width Of Square Room (In Feet) | BTU Ratio |
| Less Than 150 sq. ft. | Less Than 12 feet | 5,000 BTU |
| 150 – 225 sq. ft. | 12 feet – 15 feet | 6,000 BTU |
| 225 – 300 sq. ft. | 15 feet – 17 feet | 7,000 BTU |
| 300 – 350 sq. ft. | 17 feet – 18 feet | 8,000 BTU |
| 350 – 500 sq. ft. | 18 feet – 22 feet | 10,000 BTU |
| 500 – 650 sq. ft. | 22 feet – 25 feet | 12,000 BTU |
| 650 – 875 sq. ft. | 25 feet – 29 feet | 14,000 BTU |
| 875 – 1,100 sq. ft. | 29 feet – 33 feet | 18,000 BTU |
| 1,100 – 1,300 sq. ft. | 33 feet – 36 feet | 21,000 BTU |
| 1,300 – 1,600 sq. ft. | 36 feet – 40 feet | 25,000 BTU |
| More Than 1,600 sq. ft. | More Than 40 feet | 29,000 BTU |
Window Measurement
Now, we have an area of your room and we also defined the BTU ratio. It was crucial to identify the right size window air conditioner. But it’s not all.
In the next step, we need to measure the window where you are planning to install the appliance. Not all units can fit in every window. The larger devices can’t be installed into a small window.
Keep in mind the AC unit doesn’t need to fill the entire width of the window. A package of the product usually contains side panels to cover the side gaps. Follow the specification of the window AC unit in order to find out how much the panels can stretch and if it’s possible to install it on your windowsill.
Don’t underestimate this step because you can make a mistake and buy an incorrect size of a new unit that won’t fit in your window.
The Right Size Window Air Conditioner for Every Room
To find the right size window air conditioner you have to define three parameters. The first parameter is an area of the room where you want to have the unit. The value is set in square feet. Once, you have the area measured you can find out the BTU ratio in our table. The BTU is related to the cooling capacity so be careful and do your job properly. After defining area and BTU, you should measure the width of your window to double-check if the unit will fit.
If you want to know more about the best window air conditioners in the honest review you can check my recommendations.
There are lots of brands and models offering the pleasure of cooling comfort. It’s not easy to orient on a market and choose the best option for you but if you keep in mind our tips you can’t make a mistake.