Free to use Central Air Conditioning heat load calculator.

Calculator is based on the square foot method, with computations added for the most important values  included. Such as insulation, windows and other factors. The system is pre-set to a 72 degree indoor temp and 95 outdoor temp.
This calculator is provided for use as a super quick method of computing basic size and value conditions.
Most commonly used values are preset, you may change them at will, and keep testing your total with different combinations of values, in  as simply as 2 clicks. Since central air conditioning units are provided in increments of 1/2 ton sizes, this system should be very close to the actual units you will use. Extreme circumstances such as, shade, non vented attics, heavy air infiltration, combinations of insulation are not provided for. Homes with such conditions can only be calculated with proper heat load calculations.
Square foot methods are considered rule of thumb for quick calculations. Exact heat loads can be determined with a full heat load analysis.

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Air Conditioning Calculator


Enter the Dimensions of your home below
Enter The length in feet

Enter The width in feet

Please choose a situation that best describes the home type. (Note some home designs are set for multi floor)

Insulation Values

Click for estimate of how many windows are in the spaces to be cooled

Enter Number Of Skylights


Number of Btu's needed.

Nominal Tons

CFM's of air needed

Recommended number of 6" take off ducts




A few extra Factors

A kitchen stove can create  more than 17,000 btu's while cooking in bake mode with 1 burner running, that's almost 1.5 tons
If your system is to be installed in a home where heavy cooking will take place, be sure to upsize your system accordingly.
People can generate from 200 to 300 btu's.

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