Calories (20°C)
A Calorie (20°C) is sometimes referred to as a small calorie or gram calorie. It is a unit of energy defined as the amount of heat required to raise the temperature of one gram of water by one degree Celsius from 19.5°C to 20.5°C.
Therm (EC)
The Therm (EC) is a unit of energy primarily used in the United Kingdom for billing purposes in the gas industry. It is defined as 105.5 megajoules (MJ). The "EC" in Therm (EC) stands for European Community as it was created to standardize within European countries.