BTU to kWh — heating and cooling energy
This converter changes British Thermal Units (BTU), common in HVAC, heating and appliance ratings, into kilowatt-hours (kWh) and back. It is the right tool any time you need to compare an appliance’s heat output (rated in BTU) with your electricity meter or energy bill (measured in kWh).
Common situations where you will reach for this converter:
- Sizing an air conditioner — manufacturers rate cooling capacity in BTU/h, but your energy cost depends on kWh consumed.
- Comparing the energy content of a gas boiler (often quoted in BTU) with an electric alternative billed in kWh.
- Reading US heating-system specs alongside European energy-efficiency figures, which use kWh.
- Cross-checking energy audits that mix imperial and metric units.
How it works
Both BTU and kWh measure energy — they are just different-sized slices of the same joule-based unit system. The conversion uses fixed physical constants:
1 BTU (International Table) = 1055.05585262 joules 1 kWh = 3,600,000 joules
Dividing one by the other gives the conversion factor:
1 BTU = 1055.05585262 ÷ 3,600,000 ≈ 0.00029307 kWh 1 kWh = 3,600,000 ÷ 1055.05585262 ≈ 3412.142 BTU
Pick a direction and the tool multiplies or divides by this factor instantly.
Worked examples
Example 1 — air conditioner energy use: A room AC is rated at 10,000 BTU. How many kWh does it use if it runs for one hour at rated output?
10,000 × 0.00029307107 ≈ 2.9307 kWh
Multiply that by your electricity tariff to get the hourly running cost.
Example 2 — boiler specification: Your gas boiler’s output is listed as 30,000 BTU/h. How many kWh is that per hour?
30,000 × 0.00029307107 ≈ 8.79 kWh per hour
Example 3 — reverse direction: Your smart meter shows 5 kWh used overnight. What is that in BTU?
5 × 3412.142 ≈ 17,061 BTU
Quick-reference table
| BTU | kWh (approx.) |
|---|---|
| 1,000 | 0.293 |
| 5,000 | 1.465 |
| 10,000 | 2.931 |
| 50,000 | 14.654 |
| 100,000 | 29.307 |
Practical notes
BTU vs BTU/h: BTU is a measure of energy; BTU per hour (BTU/h) is a measure of power (rate of energy flow). Air conditioner capacity figures are BTU/h — running such a unit for exactly one hour draws that number of BTU of energy. This converter handles energy, not power, so multiply by hours of operation when working from BTU/h specs.
Which BTU definition? This tool uses the International Table (IT) BTU, the standard reference for HVAC and appliance ratings. There is also the thermochemical BTU, which differs by only a tiny fraction and is not used in consumer equipment specifications.
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