What are Air Conditioner BTUs?

In order to fully understand what kind and what size of window or portable air conditioner that you need you first need to understand British Thermal Units, or BTUs. BTUs are the traditional measurement of heat. When looking at air conditioners BTUs are used to measure the cooling capacity of your window or portable air conditioners. The higher the BTU number the more powerful and the more cooling capacity your unit has.

Most people use a measurement of around thirty BTUs for each square foot of living space that you wish to cool in your home or office. If we use that same measurement we can do some math based on a seven-thousand BTU air conditioner. If we take that seven-thousand number and divide it by thirty we get an approximated square footage of two-hundred and thirty. So, in this case seven-thousand BTUs would have enough power to cool a larger bedroom or office.

Remember though folks that bigger isn’t always better. You want to ensure that you get the proper sized unit for the room that you are trying to cool. If you purchase something with too few BTUs then your unit is going to be working overtime trying to cool the room. If you purchase something that has too much BTUs then your unit is going to be costing you extra on your electric bills and you will also develop warm and cold spots throughout the room due to the larger sized unit.

Now that we know what BTUs are and how many BTUs you need per square foot the next step is to measure the square footage of your room. This is a relatively easy calculation that can be done with a tape measure and a little bit of time. All you need to do is measure the length of one wall and the width of the other wall. Once you have this measurement you multiply the numbers together and then you have square footage. One other thing to consider is does the room have a large closet or bathroom? If so, will the door be open or will it be closed throughout most of the day? Depending on your answer here you may need to go up in BTUs to accommodate the extra square footage.

The most commonly used BTU sized air conditioners are between five-thousand and eight-thousand BTUs. These are so common due to the fact that they are ideal for standard bedrooms, dorm rooms, or small offices. While there are other larger BTU sizes out there chances are you only need one of these size. Take a look below at our top recommended window units by BTU size. If you are looking to cool your bedroom during these hot summer months then I can assure you that these products will get the job done.

5,000 BTU

These units are rated to cool rooms at around one-hundred and fifty square feet. This could be a smaller bedroom. Our top picks are:

6,000 BTU

The 6,000 BTU units are meant to cool rooms at around two-hundred square feet. Again, this is the size of an average bedroom. Our top picks are:

8,000 BTU

The 8,000 BTU units are meant for a bit larger bedrooms and can cool up to two-hundred and fifty square feet. This could even be a smaller master bedroom. Our top picks are:


Regardless if you selected one of our picks above I hope that you have learned that BTUs can play a critical role when selecting an air conditioner. While we only selected models between five-thousand and eight-thousand the window and portable air conditioner market can go as high as twenty-four thousand BTUs. When it comes to the bigger sizes though you may want to consider purchasing a more traditional split air conditioning system.