The British thermal unit (BTU or Btu) is a traditional unit of work equal to about 1055 joules. It is the amount of work needed to raise the temperature of one pound of water by one degree Fahrenheit (Physical analogue: one four-inch wooden kitchen match consumed completely generates approximately 1 BTU). In science, the joule, the SI unit of energy, has largely replaced the BTU.
The BTU/h is most often used as a measure of power in the power, steam generation, heating, and air conditioning industries, and also as a measure of agricultural energy production (BTU/kg).[verification needed] It is still used in some metric English-speaking countries (such as Canada, but notably not the United Kingdom). In North America, the heat value (energy content) of fuels is expressed in BTUs. The notation kBtu or KBTU is often used for thousand BTU, in sizing of heating systems and in the Energy Use Index (EUI) expressed as thousand BTU annual energy use per square foot of building. MBTU represents one million Btu, although the atypical notation MMBtu or mmBtu is sometimes used to represent one million BTU.
1 BTU = 0.0002930701797575255 kwh
1 BTU = 1055.56 joules