Energy & Heat

The quantity of heat required to raise the temperature of one pound of water by one degree Fahrenheit.

1,055.06 joules

The heat required to raise one gram of water by one degree Celsius, introduced by French chemists in the early nineteenth century.

4.1868 joules

The energy unit of the centimetre-gram-second system, being the work done by one dyne acting through one centimetre.

0.0000001 joules

The work performed in raising a weight of one pound through a vertical distance of one foot.

1.3558 joules

The total work performed by one mechanical horsepower sustained for a full hour.

2.685 megajoules

One kilowatt of power sustained for one hour, and the unit in which British electricity has been bought and sold since the earliest public supply.

3.6 megajoules

Exactly 100,000 British Thermal Units, adopted as the standard billing unit for gas supply across Britain.

100,000 Btu = 29.31 kilowatt-hours

One watt of power sustained for one hour, being one thousandth of a kilowatt-hour.

3,600 joules