AC Horsepower Calculator
Convert air conditioner horsepower to BTU and cooling tons instantly.
In air-conditioning, "horsepower" describes cooling capacity, not engine power. This calculator converts aircon HP into BTU per hour and cooling tons so you can size a unit to a room.
AC HP to BTU and Tons
This horsepower rating is common for split and window air conditioners in many Asian markets, where a "1 HP aircon" is understood to mean roughly 9,000 BTU/hr of cooling. One cooling ton equals 12,000 BTU/hr.
How to Use This Calculator
- Enter the aircon horsepower (e.g. 1, 1.5, 2).
- Read the BTU/hr and tonnage to match it to your room size.
Why AC "Horsepower" Means Cooling, Not Power
In many Asian markets, room air conditioners are sold by "horsepower" — but here HP is a shorthand for cooling capacity, not the compressor's mechanical power. By long-standing industry convention, 1 AC horsepower corresponds to roughly 9,000 BTU/hr of cooling, or about 0.75 of a refrigeration ton. It's a sizing label, so a "1 HP aircon" and a "1 HP motor" are completely different uses of the word.
Sizing an Air Conditioner to a Room
As a rough guide, you need about 600 BTU/hr per square metre of floor area for a typical room, more for sunny rooms, high ceilings, or many occupants. So a small bedroom of ~12 m² suits a 1 HP unit (~9,000 BTU/hr), while a living room of ~20 m² needs around 1.5–2 HP. Oversizing wastes energy and cools unevenly; undersizing runs constantly without reaching temperature.
AC Horsepower to Cooling Capacity
| AC HP | BTU/hr | Cooling tons | Suits room |
|---|---|---|---|
| 1.0 | 9,000 | 0.75 | ~12 m² |
| 1.5 | 13,500 | 1.13 | ~18 m² |
| 2.0 | 18,000 | 1.50 | ~24 m² |
| 2.5 | 22,500 | 1.88 | ~30 m² |
AC Tons to Horsepower
Going the other way — from a tonnage rating to horsepower — divide the BTU/hr by 9,000. Since one cooling ton is 12,000 BTU/hr, 1 ton ≈ 1.33 HP. This is why a "1.5 ton" AC and a "2 HP" AC are essentially the same machine: 1.5 tons = 18,000 BTU/hr = 2.0 HP.
| AC Tons | BTU/hr | Equivalent HP |
|---|---|---|
| 0.75 | 9,000 | 1.0 |
| 1.0 | 12,000 | 1.33 |
| 1.5 | 18,000 | 2.0 |
| 2.0 | 24,000 | 2.67 |
AC Horsepower to Watts — Cooling vs. Electrical Input
Two different "watts" get mixed up with aircon HP, so be careful which one you need:
- Cooling output: 1 HP ≈ 9,000 BTU/hr ≈ 2,640 watts of cooling (1 BTU/hr = 0.293 W).
- Electrical consumption: what the unit draws from the wall. A typical 1 HP unit consumes roughly 750–1,100 W depending on its efficiency (EER/inverter rating) — an inverter unit at part load can draw far less.
An air conditioner moves heat rather than generating cooling from electricity directly, which is why it delivers ~2,600 W of cooling while consuming under half that in electrical power. To estimate consumption, divide the BTU/hr rating by the unit's EER (e.g. 9,000 BTU/hr ÷ EER 10 ≈ 900 W).
Worked Example
Frequently Asked Questions
Approximately 9,000 BTU per hour. This is the industry convention for rating room air conditioners by horsepower.
One AC horsepower is about 0.75 cooling tons, since one ton equals 12,000 BTU/hr and 1 HP ≈ 9,000 BTU/hr.
No. Aircon HP describes cooling capacity (BTU), not mechanical power. It's a market convention, mainly in Asia, for sizing air conditioners.
As a rough guide, a 1 HP (9,000 BTU) unit suits a small bedroom up to about 150 sq ft. Larger rooms need 1.5–2 HP. Insulation and sun exposure also matter.
Divide the BTU/hr rating by 9,000. A 12,000 BTU unit is about 1.3 HP.
About 2 HP. A 1.5 ton unit delivers 18,000 BTU/hr, and 18,000 ÷ 9,000 = 2 AC horsepower.
Both label cooling capacity, just with different units. One ton = 12,000 BTU/hr; one AC HP ≈ 9,000 BTU/hr. So 1 ton ≈ 1.33 HP. Tons are common in India and the US; HP is common in Southeast Asia.
It delivers about 2,640 W of cooling but typically consumes 750–1,100 W of electricity, depending on the unit's EER. Inverter models can draw much less at part load.