How to Choose the Right Size Air Conditioner for Your Room

Choosing the right size air conditioner for your room is essential, and this guide will help you make an informed decision. An 18,000 BTU air conditioner is an energy star dehumidifier i.e. a powerful unit that can cool down large spaces with ease. But it's important to understand how much space you need to cool before making a purchase, so let's dive in.

Understanding BTUs and Square Feet

The first step in choosing the right AC unit is understanding British Thermal Units (BTUs). This measurement indicates how much heat an air conditioner can remove from a room per hour. The higher the BTU rating, the more powerful the unit is. As such, an 18,000 BTU air conditioner can move 18,000 units of heat per hour.

The next factor to consider is square footage. You'll need to measure your room and figure out how many square feet it contains. For example, if your room measures 15’ by 20’, then it has 300 square feet of space that need to be cooled off.

Choosing an Air Conditioner

Now that you know both your desired BTUs and square footage, you can start shopping for a suitable AC unit. Generally speaking, you’ll want 10-12 BTUs per square foot of space in order to cool off a room effectively—but this number may change depending on factors like insulation levels or sun exposure. In our example above with 300 sq ft of space, an 18K btu air conditioner should be perfect!

For more accurate calculations, use this handy online calculator which will take into account all these variables for you!


Deciding on an air conditioner size involves figuring out what kind of power you need based on British Thermal Units (BTUs) and then calculating the square footage of your room or area needing cooling off. An 18000 btu air conditioner room size is great for larger rooms but make sure to use a calculator tool to get more accurate measurements! With this guide and some simple math equations or help from a calculator tool, finding the perfect air conditioners 18000 btu or a portable air conditioner 18000 btu size for your home should be easy!