How to Determine What Size Air Conditioner You Need How to Determine What Size Air Conditioner You Need

What You'll Need
Tape measure
BTU chart

Choosing the right air conditioner unit is actually more complicated than you might imagine. There are many different air conditioners available, all with different sizes and ratings.

Air conditioners, like other heating appliances, are measured in BTUs. You need to take the time to accurately calculate the number of BTUs you really need. Choosing a unit which is too small will put too much strain on the air conditioner. Choosing a unit which is too powerful will waste more electricity than required. It's not actually the physical size of an air conditioner that's important, because many smaller units are just as powerful as larger ones. Here's how to determine what size of air conditioner you need.

Step 1 - Measuring the Room

The air conditioner that you choose to install will depend on the size of your room and your home size. It's important to spend time measuring the room to ensure that the air conditioner you choose will be powerful enough, but not overpowering. The bigger the room, the more powerful air conditioner you'll need. Use your measuring tape to work out the size of the room in feet.

An air conditioner which is too powerful will have to switch on and off more often to keep your room at the right temperature, which will end up wasting energy and money.

Step 2 - Calculating Square Footage

Calculate the square footage of your room. Multiply the length of the room in feet by the width. Use your calculator if needed. Here you just want an approximate answer, but if your room is a different shape other than a rectangle or square, you will have to think back to geometry class.

Step 3 - Calculating BTUs

Now that you know the square footage of your room, you need to work out how many BTUs you need to heat and cool it efficiently. An area of 300 square feet can normally use an air conditioner with 7,000 BTUs quite happily. This means that if your room is 600 square feet in size, you will need to choose an air conditioner with at least 14,000 BTUs.

For a more accurate answer, look on a BTU chart to find the number needed per square foot. You will be able to find these charts on the Internet, or in brochures to choose air conditioners.

Step 4 - Location

Although this calculation will give you a rough idea about the size of air conditioner you need to use, it's by no means an exact science. You will need to first consider your location, the heat in your region and how powerful an air conditioner you will need. If you live in a hotter area of the world, consider increasing the BTUs by 10 to 20% to account for the temperature difference.

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