BTU Calculator
Calculate BTU for heating or cooling a room — factors in ceiling, sun exposure, and climate.
Room
BTU
Rule of thumb
Cooling (AC)
~20 BTU/ft² baseline
Heating
25–45 BTU/ft² depending on climate
Ceiling
Scale by ceiling/8 ft
Extra
+600 per additional person, +4 000 for kitchen
BTU → tons
÷ 12 000 (HVAC tons)
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