British Thermal Unit
- The amount of heat required to raise the temperature of 1 lb of water by 1 degree Fahrenheit. Normally taken as 60° to 61°F.
|1 Btu||=||1055.06 J||1 Btu||=||252 calories|
|1 Btu||=||778.2 ft lbf||1 therm||=||1x105 Btu|
|1 Btu||=||2.928 x10-4 kWh||1 J||=||1 Nm|
In America the British thermal unit is sometimes called the heat unit.