What a "ton" of cooling means
In HVAC, a "ton" has nothing to do with weight - it is a measure of cooling power. One ton equals 12,000 BTU of heat removed per hour. Most homes need somewhere between 1.5 and 5 tons, and getting that number right is the biggest factor in whether your home stays comfortable and your bills stay reasonable.
Sizing by square footage
A quick estimate multiplies your conditioned square footage by the cooling each square foot needs, which rises with the climate. In a hot inland area like Sacramento that is around 25 BTU per square foot; milder areas need less. This tool does that math and rounds to the nearest half-ton, the way equipment is sold - a starting point before a full load calculation.
Right-sizing matters. An oversized AC short-cycles and leaves your home humid and uneven. We confirm tonnage with a Manual J load calc, free with every replacement estimate.
AC Tonnage Questions, Answered
How do you calculate AC tonnage?
AC tonnage is cooling capacity, where one ton equals 12,000 BTU per hour. To size it, estimate your home's cooling load, roughly 20 to 25 BTU per square foot in a hot inland climate like Sacramento, and divide by 12,000. An 1,800 sq ft home works out to about 3 to 3.5 tons. The calculator above does the math instantly, and a Manual J load calculation confirms it.
How many square feet will a 3-ton AC cool?
A 3-ton (36,000 BTU) air conditioner cools roughly 1,400 to 1,800 sq ft in a hot inland climate, and more in a mild or well-insulated home. Because insulation, windows, and sun exposure shift that range, treat it as a starting point and verify with a load calculation before buying.
How many tons of AC do I need for a 2,000 sq ft house?
A 2,000 sq ft home in the Sacramento area typically needs about 3.5 to 4 tons of cooling, depending on insulation, window count, and sun exposure. Tighter homes lean toward 3.5 tons; leaky or sun-heavy homes toward 4. Enter your exact square footage above for an estimate, then confirm with a Manual J.
How can I tell what tonnage my current AC is?
Check the metal data plate on the outdoor condenser and read the model number. Most brands encode capacity in it as a number divisible by 12 or 6, so 24 means 2 tons (24,000 BTU), 36 means 3 tons, and 48 means 4 tons. That nominal tonnage tells you what was installed, while a load calc tells you what the home actually needs.
How many tons is a 12,000 BTU AC unit?
12,000 BTU per hour equals exactly one ton of cooling, which is the definition of a ton. So 18,000 BTU is 1.5 tons, 24,000 is 2 tons, and 36,000 is 3 tons. Tonnage is simply BTU capacity expressed as a rounder number.
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