BTU Calculator

For cooling, plan 20-30 BTU per square foot depending on climate, insulation, and room usage. Hot climates like Arizona or Florida need closer to 30 BTU/sf, while well-insulated spaces in mild climates may only need 20 BTU/sf. Our calculator adjusts for your specific conditions including ceiling height, sun exposure, and occupancy.

Start by multiplying your square footage by 20-30 BTU for cooling. Then add 400 BTU per occupant for body heat, adjust for ceiling height (add 10% per extra foot above 8ft), and factor in sun exposure and insulation quality. Our calculator handles all these adjustments automatically based on your inputs.

A 1,000 square foot space typically needs 20,000-30,000 BTU for cooling, which is approximately 1.5-2.5 tons. The exact size depends on ceiling height, climate zone, insulation quality, window area, and typical occupancy. Use our calculator above for a precise estimate based on your specific conditions.

Divide BTU by 12,000 to get tons. For example, 24,000 BTU = 2 tons, and 36,000 BTU = 3 tons. HVAC systems are often sized in tons, where 1 ton equals 12,000 BTU/hr of cooling capacity. Our calculator shows both BTU and tonnage for easy equipment selection.

Heating BTU requirements are typically lower than cooling in mild climates but higher in cold climates. Cooling must overcome solar heat gain, internal loads from people and equipment, plus outside temperature. Heating primarily compensates for temperature differential through the building envelope and infiltration. Our calculator provides separate heating and cooling estimates for proper equipment sizing.