Raleigh, N.C. — You could be paying more to stay warm this winter.

A month after it approved a 16 percent natural gas rate increase for PSNC Energy, the North Carolina Utilities Commission on Monday approved an additional 15 percent rate increase.

The new rates, which go into effect Tuesday, mean the typical household bill will be about $3.64 more a month in the summer and $21.38 more in the winter.

Combined with May's increase, that would mean an additional $40 a month on the average bill from November through April, which are considered the winter months.

The natural gas company, which is not allowed to make a profit on fuel purchases, said it needs the increase to pay for rising natural gas costs.

PSNC public affairs officer Angie Townsend said the rate increase is a pass-through charge to customers, meaning the company is passing on to customers the added cost it pays for natural gas.

She admits it is unusual to see such spikes during the summer months.

"This is unprecedented," she said. "Prices on the wholesale market this summer have already surpassed record levels for this time of year."

Jeff Davis, the utility commission's consumer advocate, said it is difficult to explain why the increase in the price of natural gas, but says it is a problem nationwide.

"No one knows. It could be speculation. It could be tied to oil prices," he said.

The Gastonia-based PSNC serves more than 450,000 natural gas customers in North Carolina; about 40 percent of its customers are in the Triangle.

Residential customers, like Benny Morris, say the increase – along with the rising costs of fuel and groceries – means figuring out where to cut back on other expenses.

"It's hurting right much," Morris said. "It sure don't let up. What are we going to do?"

PSNC does offer what it calls an easy-payment plan in which the utility estimates a customer's bills for the next year and spreads that amount into 12 equal, monthly payments.