Percentage Calculator
Percentage calculations are everywhere in daily life — from sales discounts and tip amounts to interest rates and tes…
BTU / Air Conditioner Size Calculator
Size your air conditioner correctly for maximum comfort and efficiency. An AC that's too small will struggle on hot days; one that's too large wastes energy and short-cycles, never properly dehumidifying.
Our calculator uses the standard 25 BTU/sq ft baseline, then adjusts for ceiling height (taller ceilings mean more air to cool), number of people (each person adds heat), and sun exposure. Always round up to the nearest standard size — 12,000 BTU = 1 ton — and when in doubt between two sizes, go bigger.
Formula
BTU = Area × 25 + Height_adj + People_adj + Sunlight_adj
FAQ
How many BTUs per square foot?
A typical home needs about 25-30 BTU per square foot. Sunny rooms or upper floors may need 35-40 BTU/sq ft, while well-shaded areas may only need 20-25.
Why does proper sizing matter?
Oversized units cool too quickly and cycle on/off, wasting energy and reducing humidity control. Undersized units run constantly and never cool adequately. Both shorten compressor life.
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