“Back in the 1980s, we sold hundreds a year,” said Rich Kauffman, the sales manager at E.F.M. Automatic Heat in Emmaus, Pa., one of the oldest makers of coal-fired furnaces and boilers in the United States, in a nod to the uptick in coal sales that followed the oil crises of the 1970s.  “But that dwindled to nothing in the early 1990s — down to as many as 10 a year,” he said. “It picked up about a year ago, when we moved about 60 units, and then this year we’ve already sold 200.”  Dean Lehman, the plant manager for Hitzer Inc., a family-owned business in Berne, Ind., that makes smaller, indoor coal stoves, said his stoves were on back order until March. And Jeffery Gliem, the director of operations at the Reading Stove Company and its parent, Reading Anthracite, in Pottsville, Pa., which supplies coal and stoves to 15 states in the Northeast and Midwest, said the uptick in interest was the largest he had seen in 30 years.  “In your typical year you might have five, six, seven thousand stoves being sold,” Mr. Gliem said. “This year it was probably double that.”  The coal trend is consistent with steep increases in other forms of supplementary heating that people can use to save money — most of them less messy than coal. Home Depot reports that it has sold more than 80,000 tons of pellet fuel, a sort of compressed sawdust, for the season to date. That is an increase of 137 percent compared with the same period last year, said Jean Niemi, a company spokeswoman.  Coal may never make economic sense in areas far from where it is mined. But in places within reasonable delivery range, the price tends to be stable, compared with heating oil or natural gas. Prices for natural gas more than tripled in recent years before plunging in the last few months amid the downturn.  Coals vary in quality, but on average, a ton of coal contains about as much potential heat as 146 gallons of heating oil or 20,000 cubic feet of natural gas, according to the Energy Information Administration. A ton of anthracite, a particularly high grade of coal, can cost as little as $120 near mines in Pennsylvania. The equivalent amount of heating oil would cost roughly $380, based on the most recent prices in the state — and over $470 using prices from December 2007. An equivalent amount of natural gas would cost about $480 at current prices.  Mr. Buck said he could buy coal for $165 a ton. On a blustery afternoon recently, he was still studying the manual for his $2,300 Alaska Channing stoker, which gave off an intense heat in the den. An automated hopper in the back slowly dispensed fine anthracite coal chips into the stove’s belly, and every couple of days, Mr. Buck emptied the ash. He said he hoped the stove would cut his oil consumption in half.  “Now, somewhere, you’ve got to take into account the convenience of turning up your thermostat, versus having two tons of coal to shovel and the hopper and ashes to deal with,” Mr. Buck said. But if the $330 worth of coal in his makeshift bin “heats the house for the winter,” he added, “you can’t beat it.”  Wesley Ridlington, a homeowner in Fairbanks, Alaska, bought an outdoor coal furnace for $13,000 in March and uses it as his main source for heat and hot water.  On a recent evening, as the temperature hovered around 23 below zero, Mr. Ridlington worked to free up the rotating burning plate inside the furnace, which he figured was jammed by a pebble. He did not seem to mind the glitch, or, for that matter, loading the furnace twice a week and emptying the ash pan every night. “It takes a little bit of time,” he said, “but for the savings, it’s worth it.”  Mr. Ridlington said he was typically burning 1,500 gallons of oil each winter to heat his 3,300-square-foot home. At last year’s prices, that would have cost about $7,000, he said. This winter, he expects to burn nine tons of coal at a cost of about $1,400.  “The initial cost was expensive,” he said. “But in three to five years, it’ll be paid for, even with prices going down. And if fuel goes back up again, it’ll be even more savings.”  Rob Richards, who owns a business in Fairbanks that sells spas, pool tables, and now outdoor coal furnaces, said that when oil prices were higher, he could promise fuel cost savings of more than 75 percent and a payback of 18 months for an outdoor coal furnace. With oil prices down again, orders for furnaces have dropped off, and the savings are closer to 50 percent with a few years’ time to recoup the cost, he said.  “Still, you’re looking at a quick payback,” Mr. Richards added.  Coal was a dominant source of heat for American homes for much of the late 19th and early 20th centuries. Americans were still burning more than 50 million tons for heating in 1950, according to the federal statistics.  But coal, primarily used today in power plants and steelmaking, has not been used for heating on a large scale for decades. Cleaner and more easily distributed forms of heating fuel — including natural gas, electricity and oil — displaced coal, and residential use dropped precipitously, to 2.8 million tons by 1975, and then to less than 500,000 tons by 2000.  Even with the recovery of the last couple of years, residential use of coal in the United States, at less than 300,000 tons today and representing a fraction of 1 percent of all coal use, is “not even a blip on the screen,” said Carol Raulston, a spokeswoman for the National Mining Association.  Still, even amid the steep decline, small upticks similar to the current one have appeared from time to time, and residential use of coal never entirely went away.  In Homer, Alaska, fall storms wash crude coal onto the beach from underwater deposits. In the mountains of eastern Kentucky or the hills of central Pennsylvania, residents can simply dig it out of the ground.  “As long as people have been mining coal up there,” said John Hiett of Kentucky’s Office of Mine Safety and Licensing, “people have burned coal in their houses.”  Government data suggest that about 131,000 households use coal as their primary source of heat, with perhaps 80,000 more using it as a secondary source. Those numbers are small enough that issues relating to pollution and greenhouse gas emissions have remained largely off the radar.  Burning coal does throw fine particles into the air that can pose problems for some people, similar to the problems involved in burning wood — though wood stoves and fireplace inserts are increasingly subject to regulation to cut down on pollutants.  “Coal stoves don’t have that,” said James E. Houck, the president of Omni Environmental Services, a firm in Portland, Ore., that tests air quality. “And there’s no regulatory pressure for them to have it.”  In some localities where residential coal burning is becoming a factor, that might be changing. In Fairbanks, air quality experts suspect the increase in coal burning — along with increased wood burning — is contributing to concentrations of fine particles well above federal limits.  “We see it as a real health hazard to Fairbanks,” said Jim Conner, the Fairbanks North Star Borough’s air quality specialist.  Concerns like these have not deterred companies marketing coal. Back East, the Blaschak Coal Corporation, a midsize supplier of anthracite in Mahanoy City, Pa., still emblazons company trucks and baseball caps with images of Santa Claus lugging a sack of coal.  “Everybody’s looking at wherever they can to save money,” said Daniel Blaschak, a co-owner of the company. “ ’Cause guess what? We no longer have disposable income. We are up to our necks in debt. And there’s very few things we can’t live without, but heat is one of them.”  Tom Zeller Jr. reported from Sugarloaf, Pa., and Stefan Milkowski from Fairbanks, Alaska.  A version of this article appears in print on , on Page B1 of the New York edition with the headline: Coal Is Returning to Home Furnaces. Order Reprints| Today's Paper|Subscribe
With the cost of heating oil and natural gas prone to spikes, some are deciding coal is worth the trouble.