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Cooling · Room sizing

What size AC for a 1,200 sq ft room?

A 1,200 sq ft room with 8 ft ceilings needs about 135,921 BTU/h (11.3 tons) of cooling in a hot climate — buy a 60,000 BTU unit, or 60,000 BTU if the room gets direct sun.

By ceiling height

CeilingBTU/h (shaded)BTU/h (sunny)Tons
8 ft135,921163,10511.3
9 ft152,911183,49312.7
10 ft169,901203,88114.2

Hot-climate volumetric method (500–600 BTU/h per m³) — the same formula as our BTU calculator, where you can enter exact dimensions. In mild climates use the room-size chart's 20–25 BTU/sq ft column instead.

FAQ

How many BTU for 1,200 sq ft?
In a hot climate with 8 ft ceilings: about 135,921 BTU/h shaded, or 163,105 BTU/h with direct sun. In a mild climate the 20–25 BTU/sq ft rule gives 24,000–30,000 BTU/h — use that as the floor for insulated rooms.
How many tons is that?
135,921 BTU/h equals 11.3 tons of cooling (1 ton = 12,000 BTU/h) — about 39.9 kW.

Other sizes: 1,000 sq ft · 1,500 sq ft · any size