RALEIGH — Awarm wintercan spell trouble for utility companies hurt by a shrinking bottom line. But it could be customers who pay the price.

The gas and electric companies cannot actually raise rates if home heating use declines. But gas companies can charge what they call a Weather Normalization Adjustment (WNA). And that means your next bill could have an extra $8 to $15 on it.

The surcharge will appear whenever the weather is unusually warm and gas companies aren't selling as much of their product.

But the Public Utilities Commission points out the WNA works the other way too. During times of high demand for natural gas, consumers should get a credit on their bills.

"For a residential customer, we can say that over the long-term, he will offset his surcharges with his credits," says Gene Curtis, Public Utilities Commission Engineer. "It'll balance out."

The WNA program has been in effect since 1991. Since it has been in effect, the gas companies have been ahead in North Carolina by about three to four percent.

The program is designed to help the gas companies maintain a consistent revenue stream, so when there's low demand they don't see their earnings dive. Consumers benefit because when there's high demand, they don't see their bills skyrocket.

Electric utilities can request a rate increase, but that usually takes two or three years to accomplish.