About the BTU/h to Watts Converter
Air conditioners, heaters, furnaces and boilers are rated in BTU per hour, a measure of how fast heat is moved or produced, while electrical and heating specifications elsewhere are in watts and kilowatts. This converter turns BTU/h into watts using 1 BTU/h = 0.29307107 W. Type the rating and read the power in watts at once, with kilowatts, horsepower and tons of refrigeration beneath it. It answers questions such as how many kilowatts of cooling a 12,000 BTU/h window unit delivers, which is about 3.52 kW. Note that this is the heat moved, not the electricity used, which is usually smaller for an air conditioner. It runs in your browser.
Updated October 2026
How to use the BTU/h to Watts Converter
- 1Type the rating in BTU per hour.
- 2Read the power in watts at the top.
- 3Check kilowatts, horsepower and tons of refrigeration in the rows below.
- 4Press Copy to copy the sentence, for example 12000 BTU/h = 3516.852842 W.
- 5Change the number to try another unit.
The formula
W = BTU/h × 0.29307107. The factor comes from one BTU being 1,055.056 joules, spread over 3,600 seconds.
For the way back, multiply watts by 3.41214.
Examples
- 5,000 BTU/h = 1,465.4 W
- 8,000 BTU/h = 2,344.6 W
- 12,000 BTU/h = 3,516.9 W (1 ton)
- 24,000 BTU/h = 7,033.7 W (2 tons)
- 100,000 BTU/h = 29.31 kW
Sizing a heater or air conditioner
A rough guide for cooling is 20 BTU/h per square foot of floor, so a 300 square foot room wants about 6,000 BTU/h, which is 1.76 kW of cooling. In heating, a furnace's rating is its input or output in BTU/h, and the watts figure helps compare it with an electric heater: a 3 kW heater provides 10,236 BTU/h.
Insulation, windows, climate and sunlight change real needs, so use the figures as a starting point.
Questions about air conditioners
Why is the cooling power bigger than the electric power? An air conditioner moves heat from inside to outside, and moving heat takes less energy than making it. The ratio is the energy efficiency ratio, EER, in BTU/h per watt. An EER of 10 means 10 BTU/h of cooling for each watt of electricity.
For heaters, the watts figure is the heat output, and an electric resistance heater uses about the same in electricity. Heat pumps can deliver two to four times more heat than the power they use.
Phone and computer
The result appears as you type, under the box on a phone. A BTU/h number is a rate, so it is useful to tie it to energy and running cost. Convert the energy itself with the BTU to kWh Converter, size an appliance with the BTU Calculator, and compare engines or motors using the Horsepower Calculator.
Features
- Exact BTU/h to watt factor (0.29307107017)
- Kilowatts, horsepower and tons of refrigeration shown
- Good for air conditioner and heater ratings
- Ten significant digits
- Copy button
- Runs in your browser
Frequently asked questions
How many watts is 1 BTU/h?
About 0.29307 watts. One watt is about 3.41214 BTU per hour.
How many watts is 12,000 BTU/h?
About 3,516.85 W, or 3.52 kW. That is one ton of refrigeration.
How do I convert by hand?
Multiply the BTU/h by 0.29307. A 5,000 BTU/h air conditioner moves about 1,465 W of heat.
Does an air conditioner use that many watts of electricity?
No. The BTU/h rating is how much heat it moves. The electricity it draws is the rating divided by its efficiency ratio. A 12,000 BTU/h unit with an EER of 10 draws about 1,200 W.
Is BTU/h the same as BTU?
No. BTU is an amount of energy, BTU/h is a rate. Use the BTU to kWh converter for energy.
What is a ton of refrigeration?
It is 12,000 BTU/h, about 3.517 kW, the cooling of melting a ton of ice in a day.
Is my data uploaded?
No.
How many BTU/h is one watt?
One watt is about 3.41214 BTU per hour, so a 100 W lamp gives off about 341 BTU/h of heat.