❄️ Cooling
BTU to Tons Converter (Air Conditioning)
Enter BTU per hour and press Convert to get tons of cooling. 12,000 BTU/h is 1 ton, so a 24,000 BTU unit is 2 tons.
About the BTU to Tons Converter (Air Conditioning)
Air-conditioner capacity is quoted in tons in the US and India, in BTU/h on specification sheets and in kW in Europe. One ton of refrigeration is 12,000 BTU/h, which is 3.517 kW — the amount of heat needed to melt a ton of ice in 24 hours, which is where the name comes from.
Sizing is not just floor area: ceiling height, insulation, glazing and climate all matter. A rough starting point is 20 BTU per square foot for a normally insulated room, so a 150 sq ft bedroom needs about 3,000 BTU — far less than the 1 ton unit usually sold for it.
How the calculation works
- 1 ton of refrigeration = 12,000 BTU/h
- 1 ton = 3.517 kW · 1 kW = 3,412 BTU/h
- Tons = BTU/h ÷ 12,000
Reference values
| BTU/h | Tons | kW |
|---|---|---|
| 9,000 BTU/h | 0.75 ton | 2.64 kW |
| 12,000 BTU/h | 1 ton | 3.52 kW |
| 18,000 BTU/h | 1.5 tons | 5.28 kW |
| 24,000 BTU/h | 2 tons | 7.03 kW |
| 36,000 BTU/h | 3 tons | 10.55 kW |
| 60,000 BTU/h | 5 tons | 17.58 kW |
Worked examples
- A 1.5 ton split unit is 18,000 BTU/h, about 5.28 kW of cooling.
- A 0.75 ton window unit is 9,000 BTU/h, enough for a small bedroom.
- A 5 ton packaged unit is 60,000 BTU/h, or 17.58 kW.
Sizing a room
The 20 BTU per square foot rule is a starting point, not a specification. A west-facing room with single glazing needs closer to 30 BTU/sq ft, while a shaded, well-insulated room can manage on 15. Oversizing is the more common error: a unit that short-cycles dehumidifies poorly and feels clammy.
Common mistakes
- Confusing cooling tons with the weight of the equipment. A "1 ton" unit does not weigh a ton.
- Using the ton figure for heating, where the same word means a different capacity basis.
- Ignoring ceiling height — the per-square-foot rule assumes a standard 2.4 m ceiling.
A last check on the numbers: 37 BTU per hour works out to 0.00308333 Ton of refrigeration, and reversing that with the same factor brings you back to 37 BTU per hour. Because BTU per hour to Ton of refrigeration is a single multiplication, any tool that gives a different figure for the same input is rounding somewhere in the middle rather than only at the end.