Btu to Watts Converter
A label gives Btu per hour, but you want watts. Divide Btu/h by 3.4121 to switch.
Quick answer: multiply the result in Btu/h by 0.29307. For example, 10,000 Btu/h is 2,930.71 W, 12,000 Btu/h is 3,516.85 W and 5,000 Btu/h is 1,465.36 W.
The Btu/h to W formula
One watt is about 3.412142 Btu per hour (Wikipedia: British thermal unit).
So divide the Btu/h by 3.412142 to get watts.
Take 10,000 Btu/h. Multiply by 0.29307. The answer is 2,930.71 W.
Take 12,000 Btu/h. Multiply by 0.29307. The answer is 3,516.85 W.
Btu per hour to watts
Btu/h means British thermal units per hour, a rate of heat flow.
W means watts, the SI unit of power.
The factor 0.29307 joins the two.
How to convert Btu/h to W step by step
- Write down the result in Btu/h.
- Multiply it by 0.29307.
- The answer is in W.
- Check it against the chart above.
Example 1: 10,000 Btu/h
- Start with 10,000 Btu/h.
- 10,000 × 0.29307 = 2,930.71.
- The result is 2,930.71 W.
10,000 Btu/h = 2,930.71 W
Example 2: 12,000 Btu/h
- Start with 12,000 Btu/h.
- 12,000 × 0.29307 = 3,516.85.
- The result is 3,516.85 W.
12,000 Btu/h = 3,516.85 W
Example 3: 5,000 Btu/h
- Start with 5,000 Btu/h.
- 5,000 × 0.29307 = 1,465.36.
- The result is 1,465.36 W.
5,000 Btu/h = 1,465.36 W
A Btu on its own is energy, so this page treats Btu as Btu per hour.
Btu/h to W conversion table
| Btu/h | W | kW |
|---|---|---|
| 10,000 Btu/h | 2,930.71 W | 2.931 kW |
| 12,000 Btu/h | 3,516.85 W | 3.517 kW |
| 5,000 Btu/h | 1,465.36 W | 1.465 kW |
| 24,000 Btu/h | 7,033.7 W | 7.034 kW |
| 1,000 Btu/h | 293.07 W | 0.2931 kW |
| 36,000 Btu/h | 10,550.56 W | 10.551 kW |
| 100,000 Btu/h | 29,307.1 W | 29.307 kW |
The highlighted row, 10,000 Btu/h, is the default of the converter. The last column gives kW.
A quick mental shortcut for Btu/h to W
Divide the Btu/h by about 3.4.
So 10,000 Btu/h is about 2,930 W.
What Btu/h measures
Btu/h means British thermal units per hour, a rate of heat flow.
It is used mainly in North America for heating and cooling (Wikipedia: British thermal unit).
What W measures
W means watts, the SI unit of power.
One watt is one joule each second.
Worked example: 24,000 Btu/h
24,000 Btu/h times the factor gives 7,033.7 W.
Check it by dividing 7,033.7 by the factor, which returns 24,000.
Worked example: 5,000 Btu/h
5,000 Btu/h times the factor gives 1,465.4 W.
Check it by dividing 1,465.4 by the factor, which returns 5,000.
Btu versus Btu per hour
A Btu is an amount of energy, and Btu/h is how fast it flows.
Many labels write Btu when they mean Btu/h (Wikipedia: British thermal unit).
A small heater
A heater of 5,000 Btu/h gives about 1,465.4 W of heat.
That is a little under 1.5 kW.
A window air conditioner
A unit of 12,000 Btu/h cools about 3,516.9 W.
That is the same as 1 ton (Wikipedia: Ton of refrigeration).
Going the other way
To go back, multiply the watts by 3.4121.
So 2,930.7 W is about 10,000 Btu/h.
Check your answer
Your answer should be smaller than your starting number.
Reverse the sum and you should get your first number back.
More worked values
6,000 Btu/h is 1,758.4 W, 30,000 Btu/h is 8,792.1 W and 1,000 Btu/h is 293.07 W.
A space heater and a room
A space heater that makes 5,000 Btu/h gives about 1,465 W of heat. An electric heater that draws 1,500 W makes about 5,118 Btu/h.
This is why a 1,500 W heater is often labelled about 5,100 Btu/h.
Checking your result
Multiply the watts by 3.4121. 1,758.4 W times 3.4121 gives back 6,000 Btu/h.
More values at a glance
2,000 Btu/h is 586.14 W, 9,000 Btu/h is 2,637.6 W and 18,000 Btu/h is 5,275.3 W.
36,000 Btu/h is 10,551 W, and 48,000 Btu/h is 14,067 W.
The unit sizes
One watt is about 3.412 Btu per hour. So one kilowatt is about 3,412 Btu/h.
If a result looks very large or very small, compare it with these sizes before you use it.
Quick conversion answers
| Conversion | Result |
|---|---|
| 10,000 Btu/h | 2,930.71 W |
| 12,000 Btu/h | 3,516.85 W |
| 5,000 Btu/h | 1,465.36 W |
| 24,000 Btu/h | 7,033.7 W |
| 1,000 Btu/h | 293.07 W |
| 36,000 Btu/h | 10,550.56 W |
Round numbers for Btu/h and W
Use these round numbers to check your own answer. 50 Btu/h is 14.65 W, 500 Btu/h is 146.5 W and 5,000 Btu/h is 1,465 W.
Going the other way, 5 W is 17.06 Btu/h, 50 W is 170.6 Btu/h and 500 W is 1,706 Btu/h.
A round trip with Btu/h
Say you start with 370 Btu/h. It becomes 108.4 W. Divide that by the factor and you land on 370 Btu/h again.
Now start from 250 W instead. It becomes 853 Btu/h, and multiplying by the factor returns 250 W.
More Btu/h values
A rate of 6,000 Btu/h is 1,758.4 W, and 24,000 Btu/h is 7,033.7 W.
Going back, 1 W is about 3.4121 Btu/h.
Multiply by 0.29307 each time.
Where this conversion is used
Heating and cooling gear is rated in Btu.
Heaters, bulbs and motors are rated in watts.
Common mistakes to avoid
- Mixing up the direction. Going from Btu/h to W should make the number smaller.
- Mixing Btu and Btu/h. A Btu is energy, while Btu/h is power. This page needs Btu per hour.
- Mixing watts and watt-hours. A watt is power, and a watt-hour is energy.
- Rounding too early. The answer for 36,000 Btu/h is 10,550.56 W. Cut it to 11,000 W and you are off by about 4.3 percent, and the gap grows if you reuse it.
Related converters
Example: 1,000 Btu/h
1,000 Btu/h times the factor gives 293.07 W.
Check it by dividing 293.07 by the factor, which returns 1,000.
Example: 36,000 Btu/h
36,000 Btu/h times the factor gives 10,551 W.
Check it by dividing 10,551 by the factor, which returns 36,000.
Frequently asked questions
How do I convert Btu/h to W?
divide by 3.4121.
How many W is 10,000 Btu/h?
2,930.7 W.
How many W is 12,000 Btu/h?
3,516.9 W.
How many Btu/h is 1 W?
About 3.4121 Btu/h.
How many W is 10 Btu/h?
2.9307 W.
How many W is 100 Btu/h?
29.307 W.
Sources
- Wikipedia: British thermal unit (en.wikipedia.org)
- Wikipedia: Ton of refrigeration (en.wikipedia.org)
