Answer-‘Therm' is the unit of –

Therm is a non-SI unit of heat energy equal to 100,000 British thermal units BTU. It is approximately the energy equivalent of burning 100 cubic feet often referred to as 1 CCF of natural gas. Since Natural Gas meters measure volume and not energy content, a therm factor is used by Natural gas companies to convert the volume of gas used to its heat equivalent, and thus calculate the actual energy use.