What is therm (US)?
A US therm is a unit of energy equal to 100,000 BTU. It is used by gas utility companies in the United States as the standard billing unit for natural gas consumption.
Real-world uses
The therm is used in the United States and United Kingdom for natural gas billing. One therm equals 100,000 BTU (approximately 29.3 kWh). Residential gas bills in the US often list consumption in therms. It is also used in industrial gas metering and procurement contracts.
History
The therm was introduced as a practical unit for natural gas billing in the early 20th century, when gas supply companies needed a convenient large-scale energy unit for residential and commercial customers. It consolidated prior inconsistent measurement practices in the gas industry.
Common mistakes
Confusing the therm with the BTU—1 therm = 100,000 BTU. Also, the US therm and the UK therm differ slightly (the UK therm is based on 105.5 MJ, while the US therm is exactly 100,000 BTU ≈ 105.48 MJ). Not to be confused with the thermie (a metric unit of heat).
What is kilowatt hour?
A kilowatt hour is a unit of energy equal to 1,000 watt hours. It is the standard billing unit used by electricity providers worldwide to measure household and commercial energy consumption.
Real-world uses
The kilowatt-hour is the standard unit for electricity billing worldwide. A typical household uses 250–1,000 kWh per month. EV charging, home appliance energy consumption, and solar panel production are all expressed in kWh. Utility bills list total kWh consumed and price per kWh.
History
The kilowatt-hour became the standard billing unit for electricity in the early 20th century as public electricity grids were established. Its use is mandated for utility metering in most countries. It equals exactly 3,600,000 joules (3.6 MJ).
Common mistakes
Writing "kW/h" instead of "kWh"—the slash implies division (kW per hour), which is a rate of power change, not an energy unit. Also confusing kWh with kW: a 2 kW heater running for 4 hours uses 8 kWh of energy, not 8 kW.
When is this conversion used?
Converting between therm (US) and kilowatt hour is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region. Electricity bills use kilowatt-hours while physics calculations use joules. Converting between them is essential for energy audits, comparing appliance efficiency, and understanding power consumption.
Worked examples
1 therm (US) = 29.30722222 kilowatt hour
1 kilowatt hour = 3,600,000 joule
How to convert therm (US) to kilowatt hour
To convert therm (US) to kilowatt hour, multiply the value by 29.30722222.
To convert kilowatt hour back to therm (US), multiply by 0.03412128.
Measurement standards
The joule is the SI derived unit of energy, defined as one kilogram-metre-squared per second-squared (kg·m²/s²). The kilowatt-hour, equal to exactly 3.6 megajoules, is accepted for use with the SI by the BIPM for practical electricity metering.
Did you know?
A single bolt of lightning releases roughly 1 to 5 gigajoules of energy, yet only a small fraction reaches the ground as electrical current. Most of the energy dissipates as light, heat, and the thunder shockwave.
Quick reference: therm (US) to kilowatt hour
| therm (US) | kilowatt hour |
|---|---|
| 0.1 | 2.93072222 |
| 0.5 | 14.65361111 |
| 1 | 29.30722222 |
| 2 | 58.61444444 |
| 5 | 146.53611111 |
| 10 | 293.07222222 |
| 25 | 732.68055556 |
| 50 | 1,465.36111111 |
| 100 | 2,930.72222222 |
| 250 | 7,326.80555556 |
| 500 | 14,653.61111111 |
| 1,000 | 29,307.22222222 |
Common values
| therm (US) | kilowatt hour | |
|---|---|---|
| A food calorie (1 kcal) | 0.00003966 therm (US) | 0.00116222 kilowatt hour |
| A AA battery | 0.00008872 therm (US) | 0.0026 kilowatt hour |
| Boiling a kettle | 0.00398082 therm (US) | 0.11666667 kilowatt hour |
| Daily human diet (2000 kcal) | 0.07931302 therm (US) | 2.32444444 kilowatt hour |
| 1 gallon of gasoline | 1.24883893 therm (US) | 36.6 kilowatt hour |
Available Energy units
More therm (US) conversions
- Convert therm (US) to joule
- Convert therm (US) to kilojoule
- Convert therm (US) to kilowatt hour
- Convert therm (US) to calorie (thermochemical)
- Convert therm (US) to kilocalorie (dietary)
- Convert therm (US) to watt hour
- Convert therm (US) to megajoule
- Convert therm (US) to electronvolt
- Convert therm (US) to British thermal unit
Assumption: calorie means thermochemical calorie, and therm means US therm.