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• Understanding Energy Consumption <--
• Steps any homeowner can take to save energy
• Tight Construction
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(1) The meter reading section reports the number of cubic feet of gas (CCF) used during the current billing period. (CCF=100 cubic feet.) It shows the current reading of the gas meter, the previous meter reading, and the difference between the two.

This gas usage figure then is converted from cubic feet to therms, a measure of the heat, or energy content, of the gas. The amount of gas consumed (CCFs used) is multiplied by a BTU (British Thermal Unit) factor--the actual heat value of the gas supplied. The BTU factor may vary from month to month.

(2) Delivery charges make up 15-20 percent of the gas bill (averaged over the year) and reflect the cost to the gas company to operate and distribute gas to the home. These charges include

• a monthly customer charge, a minimum fixed amount that covers the cost of reading the meter, producing a bill, and other administrative services;
• therm usage/distribution charges, which are based on the amount of gas used (in therms) and reflect the cost of delivering gas to the home (labor, gas mains, gas transmission and distribution lines);
• an environmental recovery cost--also based on the amount of gas used--which covers costs for environmental monitoring and possible clean-up of former manufactured gas plants in the company's service territory;
• a franchise cost for Nicor's municipal franchise agreement; and
• a governmental agency adjustment to cover other governmental fees and costs.

(3) The natural gas cost accounts for the largest portion of the bill--75 to 80 percent over the course of a year. It is calculated by multiplying the amount of gas used that month (reported in the meter reading section) by the average cost-per-therm that the company pays for its gas supply.

(4) Taxes make up the remaining 5 to 10 percent of the bill and include several state and local tax levies.

The Nicor Gas bill also provides information to help the homeowner compare energy usage for the current billing period with that for the same period the previous year. The Energy Profile section reports the average daily cost, average daily therms used and total number of degree days for the two time periods, allowing the homeowner to see how much of the difference in cost and usage between the two time periods was due to variations in the weather.

Degree days are used to calculate the effect of outside air temperature on building energy consumption. Heating degree days (HDD) are a measure that indicates how much colder the outside average temperature was compared to a baseline temperature of 65°F. (This baseline reflects the observation that houses generally require heating if the outside temperature is lower than 65°.) If the average of the high and low temperatures for a particular day was 35°, that would add 30 heating degree days to the total for the billing period.

Similarly, cooling degree days (CDD) are a measure of how much warmer the outside average temperature was than 65°F.

Nicor customers can review two years of their Gas Use History by accessiing their account on the Nicor website. Information presented includes number of degree days, therms used, and cost/therm for each billing period as well as monthly data in graph form.