Heating costs for the winter are slated to jump significantly due to market fluctuations and the aftermath of Hurricane Katrina, energy experts are warning.

According to We Energies spokeswoman Beth Martin, customers can expect a 40 to 45 percent increase in the cost of heating their homes in upcoming months.

"The average residential customer paid about $790 for the whole winter (last year)," Martin said. "But this year it is predicted to be $300 to $350 more."

These predictions are not entirely due the destruction caused by the hurricane, Madison Gas and Electric spokesman Steve Kraus said.

"The prices of natural gas were high before the hurricane," Kraus said, citing supply and demand fluctuations that have created a volatile market since last winter.

Due to an exceptionally hot summer nationwide, energy companies were forced to increase their use of natural gas, resulting in a 30 percent rise in price, according to Alliant Energy spokeswoman Erin Dammen.

Energy companies have natural gas-run power plants that serve to provide extra electricity to customers when demand for energy is higher than usual.

"The hot temperatures required us to fire up natural gas back-up plants," Dammen said, referring to the increased use of air conditioning.

But natural gas prices climbed even further after the hurricane hit the Gulf Coast, Scott Smith, also a spokesman for Alliant Energy, said.

"With Katrina, some of the natural gas supply took a hit," Smith said. "And due to the decrease in supply, the price has gone up."

An initial overreaction to the amount of damage in the Gulf Coast region caused a spike in natural gas prices. After a closer look at natural gas rigs, however, prices have receded.

"When this is all said and done, prices should soften up a little," Kraus said.

In addition, because the Upper Midwest gets less than 20 percent of its natural gas stock from the Gulf, Kraus said this region will not experience as dramatic a price increase as the eastern part of the nation.

Even though the South has experienced shortages of natural gas, Smith assured that customers in the Midwest will not see similar deficiencies.

"We're not concerned about the supply of natural gas," Smith said. "We're more concerned about prices."

Due to the fluidity of the natural gas industry, the crimp in the natural gas supply will drive up costs in other areas not directly affected by the hurricane, Smith said.

The cost per unit of natural gas, which was between five and six dollars last year, rose to between nine and ten dollars just before Hurricane Katrina hit the Gulf Coast, Martin said. After the disaster, the price jumped another two dollars.

Despite the twofold increase in the price energy companies now pay for a unit of gas, Martin said customers will not see an equivalent change in their bills.

"The reason the bills will not double is because we have internal programs at work to reduce the volatility," Martin said. Energy companies can store natural gas during periods when the demand for energy lessens, she said, which can then be used in times like these, when the need for energy increases.

However, the predictions made by the energy industry in regards to heating costs are not concrete, Martin said.

"The hardest part about all of this is it's a prediction," Martin said. "It's like the stock market — you make a prediction one day, and (then) next week it could be different."

Kraus agreed, and said the actual increase in heating costs will be easier to estimate once the heating season gets closer.

Martin noted when the price of oil shifts, natural gas costs would mirror those changes, though the correlation between the two is elusive.

There are several factors that can have an effect on heating costs, Martin said.

"The three biggest things that impact the price are the New York Mercantile Exchange, natural disasters and weather fluctuations," she said.

Energy customers must take a proactive approach to the impending hike in heating costs, Dammen said.

"It's important for people to start thinking about winterizing their homes so that when the first cold-snap hits, they are prepared," Dammen said. "With the heat, it's hard to think about it now, but it's a good time to start."