BTU - British Thermal Unit

From Cornburning

The British thermal unit (BTU or Btu) is a unit of energy used in the United States. It is also still occasionally encountered in the UK, in the context of older heating and cooling systems. In most other areas, it has been replaced by the SI unit of energy, the joule (J).

A Btu is defined as the amount of heat required to raise the temperature of one pound avoirdupois of water by one degree Fahrenheit. 143 Btu is required to melt a pound of ice. As is the case with the calorie, several different definitions of the Btu exist, which are based on different water temperatures and therefore vary by about 0.5%:

See Also: Therm