February 2004
Understanding AGLC's Base Charge

Atlanta Gas Light Company (AGLC) controls part of your monthly natural gas bill, known as your base charge.

As the owner of the pipelines, AGLC must maintain the proper condition of the equipment that delivers natural gas to your home or business. This cost, along with the cost of delivery and meter reading, is recovered in the base charge.

As a user of AGLC's pipelines, you should be aware of how base charges are calculated. Base charges vary month to month for each individual account, but no matter which marketer you purchase your natural gas from, the base charge always stays the same since AGLC remains owner of the pipelines.

Each month, you pay a customer charge accounting for the fixed costs related to your gas connection, like your meter or the service lines. Also included in the base charge are fees for meter readings and other tasks. Meter readings are included in your base charge since AGLC's employees read your meter.

The column of your bill labeled DDDC stands for designated design day capacity. This figure is based on your gas usage from the coldest day of the previous year. Your DDDC factor could be different from your neighbor's. Your neighbor has different appliances, as well as different habits.

The DDDC factor remains the same all year until it's re-evaluated in April to take effect the following August. DDDC is recalculated yearly based on a 12-month usage history. The DDDC charge varies depending on the month, resulting in higher base charges during the winter and lower charges in the summer.

Calculating Heating Degree Days

Heating degree days (HDD) affect the amount of your gas bill. The more HDD during the current billing period, the more consumption increases.

Heat is generally required for your home or business when the average daily temperature falls below 65 degrees. Each degree below 65 equals one heating degree.


Low: 30 degrees Fahrenheit Average Temperature: 45 degrees

High: 60 degrees Fahrenheit Heating Degree Days: 20 (65 – 45)

The higher the HDD, the more gas needed to heat your home or business.

Billing for natural gas is unique. Each month, you pay for the amount of natural gas already consumed, unlike paying rent or your cell phone bill a month in advance. However, the base charge is similar to paying rent; you're paying to use AGLC's service lines and gas meter.

Notice the billing period and amount of consumption listed on your gas bill. The temperature during the actual billing period may be dramatically different than the temperature on the day you receive your bill. So the amount of gas used to heat your home or business during the billing period could be significantly lower or higher than the day you receive your bill.

Go to AGLC's website for more information on calculating your base charge.