The Most Important Factors in Choosing the Right Size Air Conditioner for Your Home

February 5, 2024
Air Conditioner installation in Cave Creek, AZ

For air conditioners, size usually indicates cooling power, measured in BTUs or tonnage, instead of physical size. When air conditioning units are too small, they run constantly and can’t effectively cool rooms. If the unit is too big, it will use more energy than necessary, wear out more quickly, and fail to remove enough humidity. Several factors go into determining the best size air conditioner for your home.

Calculate Your Square Footage

The square footage of a room or home is the most important information to determine the proper air conditioner size. The general rule of thumb is to multiply your square footage by 25 to calculate how many BTUs you’ll need. For instance, if you have an area of 1,000 square feet, a unit with 25,000 BTUs would be necessary.

Window air conditioners are measured with BTUs while central air systems are measured by tonnage. To calculate the tonnage you’ll need for a central air conditioning unit, calculate the BTUs and then divide the result by 12,000. Round up or down to the nearest half.


Rooms that get a lot of sunlight require more BTUs. The heat from the sunlight makes it more difficult to cool the entire room. In addition, large windows reduce energy efficiency and require more power to cool effectively. Increase the BTUs by 10% in these rooms.

Rooms That Generate Heat

Kitchens and laundry rooms are notoriously difficult to cool since ovens, stoves, and dryers increase the heat and humidity. A BTU increase of 4,000 is usually sufficient for these rooms.

If you’re interested in installing an air conditioning unit of any size in your home, you can rely on our experienced technicians at Vent Masters to provide you with the best service. In addition to air conditioner installation, repair, and maintenance, we also provide installation and repair work on heaters, air ducts, air filtration systems, and more. To learn more about any of the services we provide to the areas in and around Carefree, Arizona, contact us at Vent Masters today.

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