When you’re shopping for a portable air conditioner, the first question you should ask yourself is: What BTU air conditioner do I need?
BTU – short for British Thermal Unit – is a measurement of how much cooling power an air conditioner has. The higher the BTUs, the more cold air the unit can pump out. If you’ve ever used a small portable air conditioner in a large room, then you already know that having too-small an air conditioner for your space means it’s never going to get properly cool.
But here’s a secret: when it comes to air conditioning, bigger isn’t always better.
That’s right – while you might think that a big AC would just cool your room faster, an oversized air conditioner is actually less effective. When it’s too large for the room it’s being used in, the air conditioner cycles on and off frequently and cannot efficiently remove the humidity from the air. This leaves the air in the room feeling damp and clammy…not the dry, cool feeling we appreciate from a properly-sized air conditioner.
So before you buy a portable air conditioner, make sure you measure the square footage of the room you’re going to use it in. Then, refer to the chart below so you’ll know how to calculate air conditioner size to achieve comfortable cooling.
How to Calculate Size of Air Conditioner
|Area To Be Cooled (square feet)||Capacity Needed (BTUs per hour)|
|100 up to 150||5,000|
|150 up to 250||6,000|
|250 up to 300||7,000|
|300 up to 350||8,000|
|350 up to 400||9,000|
|400 up to 450||10,000|
|450 up to 550||12,000|
|550 up to 700||14,000|
|700 up to 1,000||18,000|
|1,000 up to 1,200||21,000|
|1,200 up to 1,400||23,000|
|1,400 up to 1,500||24,000|
|1,500 up to 2,000||30,000|
|2,000 up to 2,500||34,000|
Be sure to make adjustments if any of the following conditions apply:
- For a heavily shaded room, reduce the BTU by 10%
- For a sunny room, increase the needed BTU by 10%
- Add 600 BTUs for each person over two who will be using the room
- For kitchens, add 4,000 BTUs