Is Your AC Unit Large Enough?

An air conditioner can be a blessing during hot summer days. It can help you to cool down the indoor environment for a comfortable day even when mercury rises outside. However, sometimes your AC might shock you with a huge energy bill or it might just fail to bring down the temperature of your room. It’s usually so because the air conditioning unit is not the right size.

Why Is It Important To Make The Right Choice?

If you end up buying an AC unit that’s too small for your house, it will have to work hard to bring down room temperatures. As a result, your energy bill will be huge. On the other hand, an AC unit that’s too big for your house will leave excess humidity and consume more energy due to its size. So making the right choice is extremely important. If the AC is the right size, you can expect to get cooling without having to worry too much about energy bills.

Find The Correct Size AC Unit

Finding the right air conditioning unit size isn’t rocket-science. You just need to run some basic calculations and you will know the size of the unit that’s perfect for you.

Measure The Area Of Your House

  • Measuring a square/rectangular room: You can use a tape measure to measure the area. You need to find width and length of the room and then multiply them. You can use the same formula for square and rectangle rooms.

  • Measuring area of a room which isn’t exactly square or rectangle: If your room isn’t exactly a square, you need to divide it into smaller squares. Calculate area for all those smaller squares and then add them up to find area of the room.

  • Measuring area of a triangular room: If there are any triangular regions in your room, find its area by simply treating it as a half-square or a half-rectangle.

  • Measuring area of your home: If you are planning to install central air conditioning, you have to measure area of your entire home. This could be a daunting task especially all the equipment you have is a measuring tape. Alternatively, you can simply check the property tax statement and find area of your home.

Find The Cooling Capacity Required For Your House or Room

Once you have measured area of the room/home, it’s time to find the cooling capacity required to effectively cool it. Whether using a central AC unit or an individual AC unit, you need to measure cooling capacity as BTUs (British Thermal Units).

United States Department of Energy recommends BTUs according to area of room. Below, these recommendations are put in a table so that you can easily compare them with the area of your room. Once you do that, it will be easy to know exactly what AC size you need for your room.


Area (square feet) AC BTUs (AC size)
100 – 299 5000 – 7000
300 – 549 8000 – 12000
550 – 999 14000 – 18000
1000 – 1199 21000 – 24000
1500 – 1999 30000
2000 – 2500 43000