6XC

AC BTU Calculator

What size air conditioner do you need? BTU estimate from room size, sun exposure, occupants and kitchen use.

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Sizing an Air Conditioner

The base rule is about 20 BTU per square foot (≈ 600 BTU/m²) of floor area, then adjust: +10% for a sunny room, −10% for a shaded one, +600 BTU per person beyond two, and +4,000 BTU for kitchens. An undersized unit runs nonstop; an oversized one short-cycles and dehumidifies poorly — closest match wins.

Frequently Asked Questions

How many BTU for a 20 m² bedroom?

Roughly 20 × 600 = 12,000 BTU (a "1-ton" unit) — the most common size for standard bedrooms. Shaded north-facing rooms can drop to 9,000.

Is more BTU always better?

No. Oversized units cool the air before removing humidity, leaving the room cold but clammy, and cycle on/off inefficiently.

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