How many BTU for 800 sq ft?

In a hot climate with 8 ft ceilings: about 90,614 BTU/h shaded, or 108,737 BTU/h with direct sun. In a mild climate the 20–25 BTU/sq ft rule gives 16,000–20,000 BTU/h — use that as the floor for insulated rooms.

How many tons is that?

90,614 BTU/h equals 7.6 tons of cooling (1 ton = 12,000 BTU/h) — about 26.6 kW.

Cooling · Room sizing

What size AC for a 800 sq ft room?

A 800 sq ft room with 8 ft ceilings needs about 90,614 BTU/h (7.6 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

Ceiling	BTU/h (shaded)	BTU/h (sunny)	Tons
8 ft	90,614	108,737	7.6
9 ft	101,941	122,329	8.5
10 ft	113,267	135,921	9.4

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 800 sq ft?: In a hot climate with 8 ft ceilings: about 90,614 BTU/h shaded, or 108,737 BTU/h with direct sun. In a mild climate the 20–25 BTU/sq ft rule gives 16,000–20,000 BTU/h — use that as the floor for insulated rooms.
How many tons is that?: 90,614 BTU/h equals 7.6 tons of cooling (1 ton = 12,000 BTU/h) — about 26.6 kW.

Other sizes: 700 sq ft · 1,000 sq ft · any size