AC size guide
15x18 Room AC Size
Most 15x18 ft (270 sq ft) rooms need a 3 ton AC. A shaded room can use 2.5 ton. Pick 2 x 2 ton if the room faces west or is on the top floor.
Size for your type of room
| Room type | Cooling load | AC size |
|---|---|---|
| Shaded room, lower or middle floor | 33,004 BTU/h | 2.5 ton |
| Normal sun, middle floor | 36,244 BTU/h | 3 ton |
| West-facing or top floor | 43,210 BTU/h | 2 x 2 ton |
Monthly bill for a 3 ton AC
At 8 hours a day and ₹6 per unit (Gujarat higher slab). Change the numbers in the calculator below.
| AC type | Units per hour | Per month |
|---|---|---|
| 5-star inverter | 2.10 | ₹3,024 |
| 3-star inverter | 2.55 | ₹3,672 |
| 3-star non-inverter | 3.00 | ₹4,320 |
Check your exact room
The calculator is filled with this room size. Add ceiling height, sun, floor and people for your exact answer.
Pick a typical room, or enter your own below
Live estimate
270 sq ft · approx 2.5 Ton
Calculate for cost & models
Fine-tune: sunlight, floor, ceiling height, occupancy▾
What changes the size
- Afternoon sun on a west wall can add 10 to 15%.
- A top floor under a concrete roof adds about 10%.
- Each extra person adds about 600 BTU/h.
- A ceiling above 10 ft adds about 10% per foot.
- A kitchen or many electronics add 1,000 to 3,400 BTU/h.
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Common questions
›How many ton AC for a 15x18 room?
Most 15x18 ft (270 sq ft) rooms need a 3 ton AC. A shaded room can use 2.5 ton. Pick 2 x 2 ton if the room faces west or is on the top floor.
›What is the monthly bill for a 3 ton AC in this room?
About ₹3,024 a month for a 5-star inverter AC, at 8 hours a day and ₹6 per unit.
›15 by 18 room me kitne ton ka AC lagega?
Normal dhoop aur beech ki manzil par 3 ton ka AC. Chhaon wale room me 2.5 ton kaafi hai. Top floor ya west-facing room me 2 x 2 ton lein.
›Is a bigger AC better?
No. An oversized AC switches on and off often, removes less humidity and wastes power. Buy the right size.