Central air conditioners range in size from 600 square feet to over 3,300 square feet. The square footage is determined by its tonnage as well as the geographic location in which it will be used and the total square footage of the home where it is to be installed.
A 1 1/2-ton air conditioner in the southern United States is 600 to 900 square feet. That same air conditioner in the northern part of the United States is 700 to 1,100 square feet. Air conditioning units increase in size by half-ton capacities. In general, the steadier the climate, the smaller the air conditioner needed. The square footage range for each half-ton varies about 300 square feet, so a 2-ton air conditioner in the southern United States is 901 to 1,200 square feet.
A 1-ton air conditioner distributes air at a rate of approximately 400 cubic feet per minute. It is recommended that each square foot of a home receives 1 cubic foot of air per minute. So a home with 1,000 square feet in the southern half of the United States would need a 2-ton air conditioner. Equally, experts caution against purchasing central air conditioning units that are too large for the home because they will not be able to humidify the home properly.