Iowans using natural gas to heat their homes are turning down the thermostat and pulling out their pocketbooks. “We’ve experienced dramatically increased cost,” said Keith Denner, president of Professional Property Management, Inc., 201 South 5th St., Suite 202. “Our utility bills are three times higher than last year, but we have leases with the tenants so we must absorb the cost. We pay heat on most units.” He also said some units include utilities guaranteed to be below a certain amount. If the bill gets higher than that amount, then they split the difference with the tenants.Natural gas is measured in therms, and the average residential home uses 136 therms during January, said John Rufs, manager of Alliant Energy Communications.”Natural gas ran 52 cents last January, and we project that our customers will pay as much as $1.17 per therm this January,” he said.Rufs said the gas prices change every day because of changing market costs.However, the increase in the cost of gas is directly related to the amount of money companies must spend on each tenant. It is likely that the increase will affect rent in the fall, said Don Romig, operations manager at Gentry Management Services, 2101 Oakwood Rd.”Maybe January or February won’t be as nasty as December, but we’re definitely going to be spending more on gas bills,” he said. “This one item will definitely add to our need to have rent increases. It will be part of the reason we have to pass the rent increase to tenants.”Denner also said the increase would affect rental prices in the future but said there may be a bright side to the increase.”It will give us some upward pressure for rent but not a lot,” he said. “It will be seen as an advantage for tenants in the future to rent where utilities are included.”Some apartment complexes use predominantly electric heat and have not been affected by the higher costs.”I don’t think it has affected us too much,” said Denny Bentley, property manager of Arkae Management Inc., 4100 Lincoln Swing. “Most of our tenants pay their own utilities, and most of our units have electric heat.”Another form of heat that is unaffected by gas prices is steam. Iowa State is heated almost exclusively by a system of steam tunnels extending from the power plant and traveling throughout main campus.”The plant was built in 1908 in its present location on the east side of campus,” said Dave Miller, director of facilities and utilities for facilities planning and management. “A tunnel runs from that plant to central campus, and a series of tunnels go to the major groups of buildings.”Steam runs through the tunnels to heat the buildings, is condensed back into water and travels back to the plant in a circular path., he said. The 4.75 miles of tunnel delivers steam heat to all buildings on main campus, as well as the athletic buildings around the football stadium and the veterinary medicine complex, Miller said.The steam tunnels do not extend north of the railroad tracks.”Hawthorn Court, the Administrative Services building and the library storage building use gas heat, but they are a relatively small part of our load. All the buildings on campus are heated with steam,” he said.Rufs said trying to conserve energy is the best way for consumers to cut down their energy costs. “In the short term, being more energy efficient is probably the best way to reduce the bill and save our natural resources,” he said.