A US central system serves a whole insulated envelope at ~18–25 BTU per sq ft. A single Indian room fights direct solar gain, hotter ambient air and taller ceilings, pushing the per-room load to ~90–120 BTU per sq ft. The same 1 tons therefore covers far less area per room in India.
Push toward the lower end of the range when the space is sunny, poorly insulated, top-floor, or holds more people; the higher end applies to shaded, well-insulated spaces. For a number specific to your room, use the tonnage calculator.
| US climate zone (whole home) | Coverage |
|---|---|
| Zone 1 — Hot (FL, S.TX, AZ desert) | ~428 sq ft |
| Zone 2 — Warm (Deep South, TX) | ~480 sq ft |
| Zone 3 — Moderate (TN, NC, MO) | ~545 sq ft |
| Zone 4 — Mild (Mid-Atlantic, PNW) | ~600 sq ft |
| Zone 5 — Cool (Upper Midwest, NE) | ~666 sq ft |
| India climate (single room) | Coverage |
|---|---|
| Hot & Dry (Delhi, Jaipur, Nagpur) | ~130 sq ft |
| Hot & Humid (Mumbai, Chennai, Kolkata) | ~133 sq ft |
| Composite (Lucknow, Hyderabad) | ~144 sq ft |
| Temperate (Bengaluru, Pune) | ~179 sq ft |
India figures are per room at typical 9.5 ft ceilings; subtract ~10% for top-floor rooms under an RCC roof, since the roof factor consumes part of the capacity.
| AC size | BTU/hr | US coverage | India (per room) |
|---|---|---|---|
| 0.75 ton | 9,000 | 360–500 sq ft | 75–100 sq ft |
| 1 ton | 12,000 | 480–666 sq ft | 100–133 sq ft |
| 1.5 ton | 18,000 | 720–1,000 sq ft | 150–200 sq ft |
| 2 ton | 24,000 | 960–1,333 sq ft | 200–266 sq ft |
| 2.5 ton | 30,000 | 1,200–1,666 sq ft | 250–333 sq ft |
| 3 ton | 36,000 | 1,440–2,000 sq ft | 300–400 sq ft |
| 3.5 ton | 42,000 | 1,680–2,333 sq ft | 350–466 sq ft |
| 4 ton | 48,000 | 1,920–2,666 sq ft | 400–533 sq ft |
| 5 ton | 60,000 | 2,400–3,333 sq ft | 500–666 sq ft |
Roughly 44–61 m² in US whole-home conditions, or about 9–12 m² as a single-room split AC in hot Indian conditions.
In US conditions a 1 ton (12,000 BTU/hr) system cools roughly 480–666 sq ft depending on climate and insulation. As a single-room Indian split AC, the same 1 tons covers about 100–133 sq ft.
If your room's calculated load is well under 12,000 BTU/hr, yes — an oversized unit short-cycles, leaves humidity behind and wears the compressor. Run your exact room through the tonnage calculator before deciding.