BTU Calculator
Calculate the BTU cooling or heating load for a room based on square footage, insulation, sun exposure, occupants, and climate zone.
Total floor area of the space being cooled or heated
Standard ceilings are 8 ft. Vaulted or commercial spaces are often 10-12 ft.
How well-insulated is the space? Older buildings with no wall insulation = poor.
How much direct sun hits the exterior walls and roof during peak hours?
Count all windows in the space. Each adds ~1,000 BTU of heat gain.
How many people typically occupy the space? Each person beyond 2 adds ~400 BTU.
Your region's general climate. Cold zones need more capacity for heating; hot zones for cooling.
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