AC TONNAGE
AC TONNAGE
tons = (ft² × 20 × adj) ÷ 12,000
ft²
ppl
RESULT
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FILL IN ABOVE
Rule of thumb. 1 ton = 12,000 BTU/hr. Add 600 BTU/person above 2. For tight specs use Manual J.
About this calculator
This AC tonnage calculator returns the cooling capacity needed for a room or whole house, expressed in tons (the unit HVAC contractors quote and that residential AC equipment is rated in). 1 ton = 12,000 BTU/hr of cooling. The math is the standard residential rule of thumb — 20 BTU per square foot of conditioned area, adjusted for sun exposure and occupant count, divided by 12,000 to convert to tons. For a tighter spec on equipment over 3 tons or houses with unusual envelope construction, an HVAC contractor should run a full Manual J load calculation.