kW to BTU: Convert Kilowatts to BTU per Hour
Convert kilowatts to BTU/hr: 1 kW = 3,412 BTU/hr. Instant converter plus a table for common 1 to 25 kW heater, boiler and AC ratings with US equivalents.
BTU per hour
Formula: BTU/hr = kW × 3,412.14
Going the other way? BTU to kW converter.
kW to BTU/hr conversion table
| Kilowatts | BTU per hour |
|---|---|
| 1 kW | 3,412 BTU/hr |
| 1.5 kW | 5,118 BTU/hr |
| 2 kW | 6,824 BTU/hr |
| 2.5 kW | 8,530 BTU/hr |
| 3 kW | 10,236 BTU/hr |
| 3.5 kW | 11,942 BTU/hr |
| 5 kW | 17,061 BTU/hr |
| 6 kW | 20,473 BTU/hr |
| 7 kW | 23,885 BTU/hr |
| 8 kW | 27,297 BTU/hr |
| 10 kW | 34,121 BTU/hr |
| 12 kW | 40,946 BTU/hr |
| 18 kW | 61,419 BTU/hr |
| 24 kW | 81,891 BTU/hr |
About this conversion
Multiply kilowatts by 3,412 to get BTU per hour. This is the conversion for reading an international air conditioner, heat pump, boiler or electric heater rating in the units that US sizing charts use. A 2.5 kW split system is 8,530 BTU/hr, right between the 8,000 and 9,000 BTU room-AC sizes; a 5 kW unit is 17,061 BTU/hr, the 18k mini-split class.
For electric heaters the kW figure is both the heat output and the electrical draw. A 2 kW oil-filled radiator delivers 6,824 BTU/hr, about a third more than the largest US plug-in heater, because 230 V outlets in Europe and elsewhere carry more power than a 120 V outlet. A 6 kW electric shower or a 9 kW electric boiler are 20,000 and 31,000 BTU/hr respectively.
When sizing, remember the room load is the same in any unit. If our calculator says your room needs 6,000 BTU/hr of cooling, that is 1.76 kW, and you should look for a unit rated around 1.8–2.0 kW cooling capacity, not one rated at 1.8 kW electrical input, which would be far too large.
Need the load for a specific room rather than a unit conversion? Use the BTU calculator, which returns BTU/hr, tons, kW and watts together.
Quick answers
How many BTU is 1 kW?
3,412 BTU per hour.
How many BTU is a 2.5 kW air conditioner?
About 8,530 BTU per hour, suitable for a room of roughly 350–450 sq ft under average conditions.
How many BTU is a 24 kW boiler?
About 81,900 BTU per hour, similar to a standard 80,000 BTU US gas furnace.