How to Determine the Size of a Mini Split Air Conditioner

Calculate the square footage of the area you intend to cool with your mini-split air conditioning system. Floor area is calculated using the width of the rooms multiplied by the width of the rooms. Add the space together and determine approximately how many square feet will be serviced by the air conditioner. For example, if your mini-split is only being used to cool a one-room efficiency apartment that is 20 feet wide and 25 feet long, you will have approximately 500 square feet to cool with the air conditioner.

Determine all of the additional heat factors within your home to help get an idea of the size mini-split system you need. Although the square footage will get you started, you may need more or less cooling capacity based on other conditions. Be prepared to add more cooling capacity if your home is located in a hot climate. You should also add capacity if the home has a lot of windows that receive plenty of sunlight throughout the day. The opposite is true if many trees shade your home and windows. Poor insulation can also increase the need for capacity, as will frequent cooking in a kitchen and a large number of people living in the home.

Select 1-ton of air conditioning cooling capacity for every 500 square feet you want to cool. The size of air conditioners is listed in “tons” or “BTUs.” One ton is equal to 12,000 BTUs, or British Thermal Units. You can find the cooling capacity of an air conditioner right on the label of the product. Depending on what you learned about your home in step 2, you may want to purchase a system with additional or less capacity based on those results.