Therm
The therm (symbol, thm) is a non-SI unit of heat energy equal to 100,000 British thermal units (BTU), and approximately 105 megajoules, 29.3 kilowatt-hours, 25,200 kilocalories and 25.2 thermies. One therm is the energy content of approximately 100 cubic feet (2.83 cubic metres) of natural gas at standard temperature and pressure.