kW to BTU/h Converter
Convert kilowatts to BTU per hour — the heating and cooling capacity conversion. Results update as you type; exact factors shown.
One kilowatt is 3,412.1416 BTU per hour — see the exact factor, not a rounded rule of thumb.
How the kw to btu/h converter works
Power converts through the watt. Mechanical horsepower is 550 ft·lbf/s = 745.6999 W; metric horsepower (PS, used in European car specs) is 735.4988 W. Air-conditioner capacities are quoted in kW, BTU/h (1 W = 3.412 BTU/h) or tons of refrigeration (3.517 kW).
The UK is metric for most trade and science but keeps miles, pints, stone and mpg (with the imperial gallon) in daily life.
Common power conversions
| From | To | Units |
|---|---|---|
| 1 kW | 3,412.1416 BTU/h | kilowatt to BTU per hour |
| 1.5 kW | 5,118.2125 BTU/h | kilowatts to BTU per hour |
| 2 kW | 6,824.2833 BTU/h | kilowatts to BTU per hour |
| 2.5 kW | 8,530.3541 BTU/h | kilowatts to BTU per hour |
| 3.5 kW | 11,942.4957 BTU/h | kilowatts to BTU per hour |
| 5 kW | 17,060.7082 BTU/h | kilowatts to BTU per hour |
| 6 kW | 20,472.8498 BTU/h | kilowatts to BTU per hour |
| 7 kW | 23,884.9914 BTU/h | kilowatts to BTU per hour |
| 8 kW | 27,297.1331 BTU/h | kilowatts to BTU per hour |
| 10 kW | 34,121.4164 BTU/h | kilowatts to BTU per hour |
| 12 kW | 40,945.6996 BTU/h | kilowatts to BTU per hour |
| 20 kW | 68,242.8327 BTU/h | kilowatts to BTU per hour |
Units in this converter and their exact factors
| Unit | Symbol | One unit in watts |
|---|---|---|
| watt | W | 1 watt |
| kilowatt | kW | 1,000 watt |
| megawatt | MW | 1,000,000 watt |
| horsepower (mechanical) | hp | 745.6998715823 watt |
| metric horsepower (PS) | PS | 735.49875 watt |
| BTU per hour | BTU/h | 0.29307107 watt |
| ton of refrigeration | TR | 3,516.8528421 watt |
FAQFrequently asked questions about power conversion
How many BTU/h in a kW?
3,412.14.
What is a 3.5 kW air conditioner in BTU?
About 12,000 BTU/h — one ton of refrigeration.
Why two different ratings?
Metric countries rate air conditioners in kW; the US rates them in BTU per hour. They describe the same capacity.
What size unit do I need?
Very roughly 0.15 kW per square metre for a well-insulated room, but a proper heat-load calculation is worth doing.
What is a ton of refrigeration?
3.517 kW — the rate that would freeze one short ton of water in 24 hours.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Physical Laboratory (NPL) — United Kingdom's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.