Cooling · Room sizing
What size AC for a 250 sq ft room?
A 250 sq ft room with 8 ft ceilings needs about 28,317 BTU/h (2.4 tons) of cooling in a hot climate — buy a 30,000 BTU unit, or 36,000 BTU if the room gets direct sun.
By ceiling height
| Ceiling | BTU/h (shaded) | BTU/h (sunny) | Tons |
|---|---|---|---|
| 8 ft | 28,317 | 33,980 | 2.4 |
| 9 ft | 31,856 | 38,228 | 2.7 |
| 10 ft | 35,396 | 42,475 | 2.9 |
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 250 sq ft?
- In a hot climate with 8 ft ceilings: about 28,317 BTU/h shaded, or 33,980 BTU/h with direct sun. In a mild climate the 20–25 BTU/sq ft rule gives 5,000–6,250 BTU/h — use that as the floor for insulated rooms.
- How many tons is that?
- 28,317 BTU/h equals 2.4 tons of cooling (1 ton = 12,000 BTU/h) — about 8.3 kW.