Calories (I.T.)
The Calorie (I.T.) or International Table Calorie is defined as the amount of energy required to raise the temperature of one gram of water by one degree Celsius at a pressure of one atmosphere which is approximately 4.1868 joules.
Therm (US)
A US therm is 105,480,400 joules, which is 100,000 Btu (59°F) and roughly the energy in 100 cubic feet of natural gas. US gas bills are often given in therms.