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 0.75 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) | ~321 sq ft |
| Zone 2 — Warm (Deep South, TX) | ~360 sq ft |
| Zone 3 — Moderate (TN, NC, MO) | ~409 sq ft |
| Zone 4 — Mild (Mid-Atlantic, PNW) | ~450 sq ft |
| Zone 5 — Cool (Upper Midwest, NE) | ~500 sq ft |
| India climate (single room) | Coverage |
|---|---|
| Hot & Dry (Delhi, Jaipur, Nagpur) | ~97 sq ft |
| Hot & Humid (Mumbai, Chennai, Kolkata) | ~100 sq ft |
| Composite (Lucknow, Hyderabad) | ~108 sq ft |
| Temperate (Bengaluru, Pune) | ~134 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 33–46 m² in US whole-home conditions, or about 6–9 m² as a single-room split AC in hot Indian conditions.
In US conditions a 0.75 ton (9,000 BTU/hr) system cools roughly 360–500 sq ft depending on climate and insulation. As a single-room Indian split AC, the same 0.75 tons covers about 75–100 sq ft.
If your room's calculated load is well under 9,000 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.