HEAT UNITS.
The British Unit is the amount of heat required to raise one pound of water from 60 degrees to 61 degrees Fahrenheit. It is 251.9 times greater than the metric unit, therm or calorie, which is the amount of heat required to raise one gramme of water from 4 degrees to 5 degrees centigrade.
Joule's Equivalent—J.—is the amount of energy equivalent to a therm or calorie, the metric unit of heat. It is equal to 41,600,000 ergs.
The heat in therms generated in a wire by a current = Volt X ampere X time in seconds X 0.24.