Therm (EC)
The therm (EC) is 100,000 Btu (International Table), or about 105.5 megajoules (MJ). Gas in the United Kingdom was historically billed in therms, and the EC stands for European Community, to tell it apart from the US therm.
Calories (15°C,CIPM, 1950)
The calorie defined as CIPM, 1950 or the "15°C calorie" is a unit of energy that was historically used to quantify the amount of heat required to raise the temperature of one gram of water by one degree Celsius at 15°C. This definition was established by the International Committee for Weights and Measures (CIPM) in 1950.