AC Size Calculator

How It Works

Air conditioners are sized in tons, where one ton equals 12,000 BTU per hour of cooling capacity. The term comes from the amount of energy needed to melt one ton of ice in 24 hours. Most homes need between 1.5 and 5 tons. An oversized AC will cool the air quickly but shut off before removing enough humidity, leaving you with a cold, clammy house. An undersized unit will run constantly and never reach your thermostat setting. The sweet spot is a unit that runs for 15 to 20 minutes per cycle on the hottest days. Always have a professional perform a Manual J load calculation for a final sizing decision.