Room BTU Calculator
+600 BTU for each person beyond two
Kitchens need +4000 BTU
BTU Calculation Method
Base: the ENERGY STAR room air conditioner chart (for example 150–250 sq ft → 6,000 BTU, 350–400 sq ft → 9,000 BTU), roughly 20 BTU per square foot
Apply adjustments for climate, sun exposure, insulation, height, occupants, and kitchen
Multipliers: Sun (−10% shaded, +10% very sunny, as ENERGY STAR advises) × Height / 8 ft. Climate (0.9–1.15) and insulation (0.85–1.20) are rule-of-thumb adjustments, not part of the ENERGY STAR chart.
Additions: +600 BTU for each regular occupant beyond two, +4,000 BTU if the unit cools a kitchen
Important:Oversizing can cause short cycling and inefficiency. Undersizing won't cool effectively. Consult an HVAC professional for precise sizing.
Use this room btu calculator to compute energy & hvac results from your inputs.