Two different calculations sit in this table, because a room and a house are not the same problem.
Below 900 sq ft you are cooling a room inside an already-conditioned building. Most of its walls are interior partitions carrying almost no load, so the DOE room air conditioner chart applies and the answer is a window unit or mini-split in BTU — not a central system.
At 900 sq ft and above you are cooling a standalone envelope. Load is driven by roof, exterior wall and window area, which grow with the perimeter rather than the floor area. Perimeter rises as the square root of area, so BTU per square foot falls as homes get larger — from about 21.4 at 900 sq ft to 17.0 at 5,000 sq ft. Flat "BTU per sq ft" rules of thumb ignore this and oversize large homes badly.
India reads differently again. Indian homes are cooled room by room with individual splits rather than one ducted system, so the India column is a unit list, not a single size. Past 2,500 sq ft that stops being practical and a ducted or VRF system takes over.
| Area | Design load | BTU/sq ft | US | India |
|---|---|---|---|---|
| 100 sq ft | 2,200 BTU/hr | 22 | 5,000 BTU window or portable unit | 1 ton split |
| 150 sq ft | 3,300 BTU/hr | 22 | 5,000 BTU window or portable unit | 1.5 ton split |
| 180 sq ft | 4,000 BTU/hr | 22 | 6,000 BTU window or portable unit | 1.5 ton split |
| 200 sq ft | 4,400 BTU/hr | 22 | 6,000 BTU window or portable unit | 2 ton split |
| 300 sq ft | 6,600 BTU/hr | 22 | 7,000 BTU window or portable unit | 2.5 ton split |
| 350 sq ft | 7,700 BTU/hr | 22 | 8,000 BTU window or portable unit | 2 splits — 1T + 1.5T |
| 400 sq ft | 8,800 BTU/hr | 22 | 9,000 BTU window unit or mini-split | 2 splits — 1T + 2T |
| 450 sq ft | 9,900 BTU/hr | 22 | 10,000 BTU window unit or mini-split | 3 splits — 1.5T + 1T + 1T |
| 500 sq ft | 11,000 BTU/hr | 22 | 12,000 BTU window unit or mini-split | 3 splits — 1.5T + 1T + 1T |
| 600 sq ft | 13,200 BTU/hr | 22 | 14,000 BTU window unit or mini-split | 3 splits — 1.5T + 1.5T + 1.5T |
| 800 sq ft | 17,600 BTU/hr | 22 | 18,000 BTU mini-split | 4 splits — 2T + 1.5T + 1.5T + 1.5T |
| 900 sq ft | 19,300 BTU/hr | 21.4 | 2 ton system | 4 splits — 2.5T + 1.5T + 1.5T + 1.5T |
| 1,000 sq ft | 21,000 BTU/hr | 21.0 | 2 ton system | 5 splits — 2.5T + 1T + 1T + 1T + 1T |
| 1,100 sq ft | 22,700 BTU/hr | 20.7 | 2 ton system | 5 splits — 2.5T + 1.5T + 1.5T + 1.5T + 1.5T |
| 1,200 sq ft | 24,400 BTU/hr | 20.4 | 2.5 ton system | 5 splits — 2.5T + 1.5T + 1.5T + 1.5T + 1.5T |
| 1,300 sq ft | 26,100 BTU/hr | 20.1 | 2.5 ton system | 6 splits — 2.5T + 1T + 1T + 1T + 1T + 1T |
| 1,400 sq ft | 27,800 BTU/hr | 19.9 | 2.5 ton system | 6 splits — 2.5T + 1.5T + 1.5T + 1.5T + 1.5T + 1.5T |
| 1,500 sq ft | 29,500 BTU/hr | 19.7 | 2.5 ton system | 6 splits — 2.5T + 1.5T + 1.5T + 1.5T + 1.5T + 1.5T |
| 1,600 sq ft | 31,200 BTU/hr | 19.5 | 3 ton system | 7 splits — 2.5T + 1.5T + 1.5T + 1.5T + 1.5T + 1.5T + 1.5T |
| 1,800 sq ft | 34,500 BTU/hr | 19.2 | 3 ton system | 7 splits — 2.5T + 1.5T + 1.5T + 1.5T + 1.5T + 1.5T + 1.5T |
| 2,000 sq ft | 37,800 BTU/hr | 18.9 | 3.5 ton system | 8 splits — 2.5T + 1.5T + 1.5T + 1.5T + 1.5T + 1.5T + 1.5T + 1.5T |
| 2,200 sq ft | 41,000 BTU/hr | 18.6 | 3.5 ton system | ducted or VRF, ~10.0 ton design load |
| 2,400 sq ft | 44,200 BTU/hr | 18.4 | 4 ton system | ducted or VRF, ~10.0 ton design load |
| 2,500 sq ft | 45,800 BTU/hr | 18.3 | 4 ton system | ducted or VRF, ~11.0 ton design load |
| 2,800 sq ft | 50,600 BTU/hr | 18.1 | 5 ton system | ducted or VRF, ~12.0 ton design load |
| 3,000 sq ft | 53,800 BTU/hr | 17.9 | 5 ton system | ducted or VRF, ~13.5 ton design load |
| 3,200 sq ft | 57,000 BTU/hr | 17.8 | 5 ton system | ducted or VRF, ~13.5 ton design load |
| 3,500 sq ft | 61,700 BTU/hr | 17.6 | 2 × 3 ton systems | ducted or VRF, ~14.5 ton design load |
| 4,000 sq ft | 69,500 BTU/hr | 17.4 | 2 × 3 ton systems | ducted or VRF, ~16.5 ton design load |
| 4,500 sq ft | 77,300 BTU/hr | 17.2 | 2 × 3.5 ton systems | ducted or VRF, ~18.5 ton design load |
| 5,000 sq ft | 85,000 BTU/hr | 17.0 | 2 × 4 ton systems | ducted or VRF, ~20.5 ton design load |
Every row links to a full page with climate-zone adjustments, room dimensions and the electrical requirements for that capacity.
These are estimates at 8 ft ceilings (9.5 ft for India), average insulation and normal sun exposure. A top-floor flat under an RCC roof, a west-facing glass wall, a kitchen, or a room holding eight people will all push the real number up — by 30% or more in combination. Run the full tonnage calculator with your actual room data, and for a US install have a contractor run a proper Manual J before buying.
In a moderate US climate a 1 ton system covers roughly 550-600 sq ft of whole-home area. In hot Indian conditions the same ton covers about 120 sq ft of a single room, because room loads run near 100 BTU per sq ft.
No, fewer. Cooling load follows the building envelope, and envelope area grows more slowly than floor area. The rate falls from about 21.4 BTU per sq ft at 900 sq ft to 17.0 at 5,000 sq ft.
Residential split systems stop at 5 tons (60,000 BTU). Homes with a larger load use two or more systems, usually one per floor or wing.