HVAC Load Calculator
An easy-to-use HVAC tool for calculating necessary thermal output capacity (in BTUs)
This tool is based on the square foot method, with computations added for the most important values included, such as insulation, windows, and other contributing factors.
The system is pre-set to a 72-degree indoor temperature and a 95-degree outdoor temperature.
Select your region and input the height of the zone as well as the area (length times width). The tool has various factors pre-set with the most commonly used values but may be changed at will by clicking the “Additional Factors” button to expose these additional fields.
Since most air conditioning units are provided in increments of ½ a ton (6,000 BTU/hour) sizes, this system should be quite close to the actual units that will be used.
Note: This tool is provided strictly as a quick method of computing general size and value conditions. Square foot methods are considered rule of thumb for use in quick calculations. The exact thermal load can be determined by using a full heat load analysis.
Disclaimer: The recommended BTU loads were determined in good faith and are intended for general informative purposes only. We do not take responsibility for or guarantee any completeness, reliability, or accuracy of this information. There can be several other unique factors in certain applications that significantly affect and even falsify these values. You should always consult a licensed design engineer for the most accurate measurements and values, which can only be truly obtained after a thorough inspection of the job site is performed and all related factors are determined.