Before buying an air conditioner, you have to make the AC tonnage calculation. Not sizing an AC unit properly can cause $100s in wasted unit costs or future electricity costs.

You are watching: How many square feet in a ton

According to the DOE,

“…an air conditioner generally needs 20 BTU for each square foot of living space.”

We need to convert BTU to tonnage. 1 ton equals 12,000 BTU. That means that, on average, we will need 0.0016 tons per square foot.

To properly get the tonnage of the AC you need, you can use the AC tonnage calculator here:


For example, a standard 1,500 sq ft house would need a 2.5-ton air conditioner. To help us out, here is a quick table showing how many tons (and BTU) air conditioners we need for certain square footage:

Tonnage Table

Area (Square Feet):BTUTonnage
600 sq ft12,000 BTU1 Ton
900 sq ft18,000 BTU1.5 Tons
1,200 sq ft24,000 BTU2 Tons
1,500 sq ft30,000 BTU2.5 Tons
1,800 sq ft36,000 BTU3 Tons
2,100 sq ft42,000 BTU3.5 Tons
2,400 sq ft48,000 BTU4 Tons
2,700 sq ft54,000 BTU4.5 Tons
3,000 sq ft60,000 BTU5 Tons
3,300 sq ft66,000 BTU5.5 Tons
3,600 sq ft72,000 BTU6 Tons

Here is the most frequently asked question about tonnage, BTU, and area (square footage):

How Many Tons Of AC Per Square Foot? (Tonnage Per Square Foot)

Simple answer: You need 0.0016 tons of AC per square foot.

In short, if you’re looking to cool down a 600 sq ft area, you would need:

AC Capacity = 600 sq ft * 0.0016 tons/sq ft = 1 Ton

In general, for every 600 sq ft, you need 1 ton of AC. This is a general estimate.

You can use the ‘tonnage per square foot’ formula to calculate how many tons of AC you need. Here is the formula:

AC Capacity (Tonnage) = (INSERT AREA IN SQ FT) * 0.0016 tons/sq ft

You can insert the area and calculate how many tons of AC you need per certain square footage.

When you calculate the tonnage, you can check out several 1-4 ton mini-split air conditioners here:

Hope this helps. If you have any questions, you can pose them in the comments below.


Related posts:
Categories AC Calculators And Converters Post navigation
Power Consumption Calculator: How Much Electricity You Spend?
AFUE Rating For Furnaces: How To Calculate AFUE Savings? (80 vs 94 AFUE Example)

44 thoughts on “AC Tonnage Calculator: Insert Tons, Get Square Footage”

*

Based on the tables & calculations I can find online, my unit should be somewhere between 4.5 tons and almost 6 tons.

I would expect an under-spec’d system to run all the time just trying to keep up. But ours does not. We had an A/C service come out recently and he suggested that we add more return ducts.

See more: A Recipe Calls For 28 Oz Equals How Many Cups Conversion, 28 Ounces To Cups

I am trying to grasp what the symptoms are when the unit is under-sized. I would have expected the unit to burn out long before now if it was working to too hard.

What am I missing?

Reply
*

I bought a 15 year old two story home in Houston. My appraisal shows the house is 4300 sqft (2400 on first floor and 1900 on second floor). There’s high open ceiling from entrance all the way through the living room. Property faces west, so it gets a lot of evening sun in the front. The house has tall high ceiling glass windows in the back, but the morning sun in the back is partly shaded by high a ceiling patio. The house seems to have good insulation (but it is 15 years old). The house has the original system installed by the builder with two 3 ton units (Evaporator coils were changed in 2013). I am about to replace this system. Is this tonnage adequate for this house? Should I go to a 4 ton/3.5 ton combo or perhaps a 5 ton/4 ton combo? At what point do we run into the problems of an oversized AC?