Ccf: A volumetric measure of natural gas. It represents the amount of gas contained in a space equal to one hundred cubic feet.

Therm: A measurement of energy, or heat, equal to 100,000 BTU (British thermal units). The same volume of gas may contain different amounts of energy.

BTU: The amount of heat it takes to raise the temperature of one pound of water by one degree Fahrenheit.

Rates were recalculated in order to assure that this unit change from ccf to therms is accurately reflected in bills. At the same time, Unitil’s distribution rates also changed effective March 1, 2018. The overall result of this change in distribution rates is a small decrease in customer bills.  

Your March bill will show usage and rates in both ccfs and therms.  This is because the conversion to therms takes place on March 1^st whereas most March bills will also include some February usage.  For instance, if your bill cycle ends on the 15^th of March, then only those 15 days will appear on your bill as being in therms.  For all other days of that billing cycle, which occurred in February, the units and charges will be in ccfs. After March, all monthly invoices will be solely in therms.

There are several benefits to converting to therms.  First, therm billing assures customers are being billed for the energy they are using rather than the volume. Second, therm billing aligns the way customers are billed with the same way Unitil purchases gas in the marketplace, in therms. Third, the EnergyGuide and Energy Star labels appearing on household gas appliances are based in therms so this change will make it easier for customers to compare appliances.

The BTU value of the natural gas that the Company purchases is measured using tools such as a chromatograph or calorimeter. These devices are calibrated on a monthly basis to ensure that they are accurately measuring the BTU content of the gas.

The heat content of natural gas does not change while being distributed to your home.