BTU: British Thermal Unit: One BTU is the amount of heat required to raise the temperature of one pound of water one degree Fahrenheit. A more practical definition would be: how much gas an appliance will use to produce heat or cooling. As a result, gas appliances are sized by a BTU rating. 100,000 BTU's equal 1 therm. For example, a 400,000 BTU heater, when in use, would use 4 therms of gas per hour. A 30,000 BTU range would use .3 therms per hour of use.

CCF: Hundred of Cubic Feet: Method used for gas measurement. The quantity of gas at a temperature of sixty degrees Fahrenheit and a pressure of 14.73 pounds per square inch makes up one cubic foot.

Billing Factor: An adjuster used to convert CCF into therms. It adjusts the amount of gas used to reflect the heat value of the gas at a given altitude. The heating value can vary from month to month; therefore, the billing factor is not always the same.

Therm: A therm is approximately 100,000 BTUs. It is a standard unit of measurement. CCFs are converted to therms for purposes of billing.