But it will take more than five years to recover the cost. More than half of the 101.5 million households in the United States heat with natural gas, the government says. Many homes switched to natural gas over the years because of its reputation as a cheaper fuel. About 30 million households use electricity for heat, and 7.7 million rely on heating oil. Brenda Ramsby of East Lansing, Mich., who gets heat from a geothermal pump, is already thinking ahead to next winter when the state's natural gas companies go through deregulation.
House hunters are alert to energy costs, too.