Uses the same engine as the full calculator (occupants 2, one large window assumed).
| Cooling load | — |
Common 450 sq ft room dimensions: 18×25 ft, 15×30 ft. The load depends on area, not shape.
US (single room): at roughly 22 BTU per sq ft, 450 sq ft carries about 9,900 BTU/hr, which the DOE room air conditioner chart matches to a 10,000 BTU window unit or mini-split. The smallest residential central system is 18,000 BTU — installing one here would oversize the room by 1.8× and cause short-cycling.
| US climate zone | Cooling load | Room unit |
|---|---|---|
| Zone 1 — Hot (FL, S.TX, AZ desert) | 12,600 BTU/hr | 12,000 BTU |
| Zone 2 — Warm (Deep South, TX) | 11,300 BTU/hr | 12,000 BTU |
| Zone 3 — Moderate (TN, NC, MO) | 9,900 BTU/hr | 10,000 BTU |
| Zone 4 — Mild (Mid-Atlantic, PNW) | 9,000 BTU/hr | 9,000 BTU |
| Zone 5 — Cool (Upper Midwest, New England) | 8,100 BTU/hr | 8,000 BTU |
India (room by room): Indian homes are cooled one room at a time, so 450 sq ft is not one big unit — it is 3 splits — 1.5T + 1T + 1T, about 3.5 ton in total. A typical layout at this size breaks down as:
| Room | Approx. area | Split size |
|---|---|---|
| Hall / living | ~126 sq ft | 1.5 ton |
| Bedroom 1 | ~104 sq ft | 1 ton |
| Bedroom 2 | ~104 sq ft | 1 ton |
Only cool the rooms you use. Sizing every room at once is how Indian households end up with two unused units and a higher connected load than the sanctioned supply allows — check your meter's sanctioned load before adding the last unit.
Figures assume 8 ft ceilings (9.5 ft for India), average insulation and normal sun. Your real number can swing ±30% — run the full tonnage calculator with your actual room data.
0.75 ton 1 ton 1.5 ton 2 ton 2.5 ton 3 ton 3.5 ton 4 ton 5 ton
About 9,900 BTU/hr in a moderate US climate, which matches a 10,000 BTU window unit or mini-split.
No. The smallest residential central system is 18,000 BTU, which is 1.8× the load of a 450 sq ft room. It would short-cycle and leave the room cold and humid.
3 splits — 1.5T + 1T + 1T — about 3.5 ton in total, cooling room by room.
100 sq ft 120 sq ft 150 sq ft 180 sq ft 200 sq ft 250 sq ft 350 sq ft 400 sq ft 450 sq ft 500 sq ft 600 sq ft 700 sq ft 800 sq ft 900 sq ft 1,000 sq ft 1,100 sq ft 1,200 sq ft 1,300 sq ft 1,400 sq ft 1,500 sq ft 1,600 sq ft 1,800 sq ft 2,000 sq ft 2,200 sq ft 2,400 sq ft 2,500 sq ft 2,800 sq ft 3,000 sq ft 3,200 sq ft 3,500 sq ft 4,000 sq ft 4,500 sq ft 5,000 sq ft
How these figures are derived: BTU per square foot, honestly · refine for your exact room with the full tonnage calculator.