Therm (thm)
100,000 BTU (about 105.48 MJ). US natural gas bills are measured in therms.
1 therm = 105,480,400 joules (exactly).
About the therm
Gas bills gave the therm its place in daily life. It is defined as 100,000 British thermal units, so its size depends on which BTU is meant. The figure used here, 105,480,400 joules or about 29.30 kWh, is the US therm, built on a BTU defined at 59 degrees Fahrenheit. The European Community version, based on the ISO BTU, is 105,506,000 joules, and the UK value is about 105,505,585 joules.
In the United States, natural gas is billed in therms or in CCF, hundreds of cubic feet. Pipeline companies adopted the decatherm, 10 therms or a million BTU, around 1972 to simplify invoicing, and roughly 1,000 cubic feet of gas holds about one decatherm.
Britain moved the other way. Regulations replaced therms with joules from 1999, retail customers now see kilowatt-hours, and only the wholesale market still quotes pence per therm. The EIA lists one therm as 100,000 Btu, and the Btu itself is the heat needed to warm a pound of water by one degree Fahrenheit.
Sources: Wikipedia: Therm; EIA: British thermal units (Btu); Wikipedia: British thermal unit
Therm conversion chart
1 therm expressed in every other energy unit:
| Unit | 1 therm |
|---|---|
| Joules | 105,480,400 |
| Kilojoules | 105,480.4 |
| Watt-hours | 29,300.11111 |
| Kilowatt-hours | 29.30011111 |
| British Thermal Units | 99,976.12898 |
| Calories | 25,210,420.65 |
| Kilocalories | 25,210.42065 |
| Megajoules | 105.4804 |
| Gigajoules | 0.1054804 |
| Megawatt-hours | 0.02930011111 |
| Foot-pounds | 77,798,350.53 |
| Millijoules | 105,480,400,000 |
| Electronvolts | 6.583568738×10²⁶ |
| Kiloelectronvolts | 6.583568738×10²³ |
| Megaelectronvolts | 6.583568738×10²⁰ |
| Gigaelectronvolts | 6.583568738×10¹⁷ |
| Tons Of TNT | 0.02521042065 |
| Tonnes Of Oil Equivalent | 0.002519356071 |
| Quads | 9.997612898×10⁻¹¹ |
| Ergs | 1.054804×10¹⁵ |
| Calories (IT) | 25,193,560.71 |
| Kilogram-force Meters | 10,756,007.4 |
| Horsepower-hours | 39.29209623 |
| Liter-atmospheres | 1,041,010.609 |
More US customary units
- quad (energy)
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