Reference chart
BTU Chart by Room Size
Cooling capacity for room sizes from 100 to 1,500 sq ft, at 8 ft ceilings: 20–25 BTU/sq ft in mild climates, or the hot-climate volumetric figure used by our BTU calculator.
| Sq ft | m² | Mild climate (BTU/h) | Hot climate (BTU/h) | Tons (hot) |
|---|---|---|---|---|
| 100 | 9 | 2,000–2,500 | 11,334 | 0.9 |
| 150 | 14 | 3,000–3,750 | 17,001 | 1.4 |
| 200 | 19 | 4,000–5,000 | 22,668 | 1.9 |
| 250 | 23 | 5,000–6,250 | 28,335 | 2.4 |
| 300 | 28 | 6,000–7,500 | 34,003 | 2.8 |
| 350 | 33 | 7,000–8,750 | 39,670 | 3.3 |
| 400 | 37 | 8,000–10,000 | 45,337 | 3.8 |
| 450 | 42 | 9,000–11,250 | 51,004 | 4.3 |
| 500 | 46 | 10,000–12,500 | 56,671 | 4.7 |
| 600 | 56 | 12,000–15,000 | 68,005 | 5.7 |
| 700 | 65 | 14,000–17,500 | 79,339 | 6.6 |
| 800 | 74 | 16,000–20,000 | 90,673 | 7.6 |
| 1,000 | 93 | 20,000–25,000 | 113,342 | 9.4 |
| 1,200 | 111 | 24,000–30,000 | 136,010 | 11.3 |
| 1,500 | 139 | 30,000–37,500 | 170,013 | 14.2 |
Sun-exposed rooms: add 20% to the hot-climate column. For an exact number with your ceiling height and sun exposure, use the BTU calculator or convert results with BTU to tons.
FAQ
- How many BTU per square foot?
- In mild climates plan 20–25 BTU per square foot with 8-foot ceilings. In hot climates, volumetric sizing works out to roughly 110 BTU per square foot — the difference is design temperature, solar gain, and construction, which is why this chart shows both columns.
- Which column should I use?
- Use the mild column for temperate climates with insulated construction, and the hot column for tropical or desert climates, sun-exposed rooms, or light construction. If you're between the two, calculate your exact room instead of reading the chart.
- Does ceiling height change these numbers?
- Yes — the chart assumes 8 ft (2.44 m) ceilings. Add proportionally for higher ceilings: a 10 ft ceiling adds 25% to the load. The calculator works from volume, so it handles this automatically.