Which AC tonnage do you need for your room size in India?
People search this as “which ton AC for 150 sq ft room in India” · updated 2026-08
Short answer
As a rule of thumb in India, use roughly 0.06 ton per square foot: up to 120 sq ft needs 1 ton, 120-180 sq ft needs 1.5 ton, and 180-250 sq ft needs 2 ton. Add half a ton if the room is on the top floor, gets direct afternoon sun, has more than two people regularly, or opens into a kitchen.
- Undersized ACs run non-stop and cost more to run than a correctly sized one.
- Oversized ACs cool fast but cycle off before removing humidity, leaving the room clammy.
- Top-floor rooms in North Indian summers need roughly 0.5 ton more than the chart says.
- Ceiling height above 10 ft also pushes you one step up.
Room size to tonnage chart
| Room area | Standard room | Top floor / heavy sun |
|---|---|---|
| Up to 120 sq ft | 1 ton | 1.5 ton |
| 120-180 sq ft | 1.5 ton | 1.8-2 ton |
| 180-250 sq ft | 2 ton | 2.5 ton |
| 250+ sq ft | 2 ton + second unit | Consider two units or a cassette AC |
Adjustments that actually matter
- Top floor with no insulation: +0.5 ton.
- West or south-west facing window with afternoon sun: +0.5 ton.
- Room used by 4+ people (living room): +0.5 ton.
- Open kitchen or attached glass balcony: +0.5 ton.
- Ground floor, shaded, single occupant: you can stay at the base figure.
What to ask in the shop
- What is the ISEER rating of this exact model, not the series?
- Is the cooling capacity in watts printed on the energy label?
- Is the condenser copper, and what is the warranty on it?
Common follow-up questions
Is a bigger AC always better?
No. An oversized AC reaches the set temperature quickly and switches off before it can dehumidify, which leaves the room cold but sticky and wears the compressor with frequent cycling.
Does a 1.5 ton AC consume much more power than a 1 ton?
Roughly 30-40% more at full load, but a correctly sized 1.5 ton in a large room often uses less power overall than a 1 ton running continuously.
Go deeper with the full guide
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