Once the environmentalist's home companion, a non-petroleum source of heat, the wood stove went on to become an ecological embarrassment. As the nation's hills and valleys filled with eye-stinging blue smoke each winter, communities around the country adopted air pollution controls to restrict stove use.
Now an efficient new generation of wood-burning heaters has come to market. And as the Mideast crisis wears on, many in the small industry predict that rising oil prices, as they did in 1973, will revive consumer interest in heating with wood.
"People will start again to look for alternative sources," predicts Winston Christensen, vice president of Winston Stove Co., in Chino.
"In previous crises, there was a big boom in wood stoves," Christensen said Wednesday. "Except that now they're going to pellets."
The new wood heaters include stoves that run on wood-based pellets the size and shape of rabbit food, stoves that use catalytic converters much like those in automobiles and high-tech versions of the so-called airtight stoves--or "black boxes"--that became popular in the 1970s.
What they all have in common is dramatically reduced emissions of unburned fuel, better known as smoke.
"You can almost breathe that air," Christensen says of his stove's emissions.
"Before the industry really got into the clean burn, one stove polluted as much as 20 of the current ones," says Dean Moore, an owner of Forden's, a fireplace and wood stove retailer in San Luis Obispo. "The new stoves are super products."
They are also safer. "Winter haze," as wood smoke came to be known, was found to contain carbon monoxide, formaldehyde and other substances, some of which cause cancer or harm the human lung.
In 1986, the Natural Resources Defense Council, an environmental group, pressed the U.S. Environmental Protection Agency to control wood-stove emissions. Meanwhile, Oregon had developed high-efficiency standards for stoves. The EPA adopted the Oregon standards for use around the country, and stove engineers went back to their workshops. The result was a new gallery of stoves.
The EPA standards do not affect fireplaces, however, and some communities either have already imposed or are pondering restrictions on the traditional hearth. High-tech stove manufacturers and air-pollution control experts agree that such restrictions will encourage more use of the new wood heaters.
"About 85% of new homes built here have one or more fireplaces," says Bob Carr, director of the San Luis Obispo County Air Pollution Control District, which this month will propose regulations on fireplaces and fireplace inserts. "We're adding the potential for a lot of air pollution."
Other communities around the country have already banned fireplaces outright.
An estimated 12 million U.S. homes are heated with wood. From 300,000 to 400,000 high-tech stoves were sold nationally in 1989, said Ron Pulone, owner of Sunset Fireplace Fixtures Inc. in City of Industry and past president of the Wood Heating Alliance, a trade group. "But the pellet stoves were nowhere close to that, because they have just started," he said.
Southern California is not often considered a big market for wood stoves, and the South Coast Air Quality Management District does not consider wood smoke a major source of pollution.
But the pellet stove, arguably the most unusual of the new designs, could still be popular here, according to Christensen.
"I designed our stoves to appeal to women," he says of his small stoves, which weigh a third as much as stoves of the 1970s. "It's becoming a woman's market more than it was before. And a little stove can heat the whole house."
Pellets themselves aren't new, having been used for decades in commercial and industrial furnaces and boilers. Only recently, however, have pellets been produced that are clean enough for home use.
The Winston pellet stoves are run by a thermostat, which controls an augur feeding the tiny pellets slowly into the flame. A fan distributes the heated air. Fuel is easier to handle, and cleaner, than logs. Less than 1% ash is left after burning, says Christensen, which makes cleanup easier. The stoves burn so efficiently that they can be vented like a clothes dryer, without the need for a masonry chimney or triple-wall insulated pipe, as required for a traditional fireplace or stove.
"The people who are really starting to go for it are people in condominums, who want a fireplace," says Christensen. "If you want to put it up against a wall you just poke a hole through."
"I think Southern California is going to be one of our biggest markets," says Christensen, "because if you look around, everyone has heat."
Winston sold 2,400 stoves in 1989, at $1,700 to $2,000 retail, and Christensen expects to sell 10,000 in 1991, in markets the company has already opened in Washington, Oregon, Northern California, Utah, Idaho, and other western states, as well as Missouri, Western Canada and on the Eastern Seaboard.
Still, the pellet stove has its limitations. For one thing, both the augur and fan require electricity. When the lights go out, so does the owner's heat. Also, pellets, currently made mostly of sawdust, are not yet widely available.
Six retail outlets in Southern California sell pellets produced since 1987 by Pasadena-based Lignetics Inc., co-founded by William H. Pickering, former director of Jet Propulsion Laboratory.
Christensen estimates that about 45 pellet mills are operating nationally, with another 20 to 25 in planning. He contends that pellet stoves could provide as much as 10% of U.S. heating needs some day, based on available forest waste, cardboard and other materials which could be processed into fuel. The average two- to three-bedroom home in Southern California would annually cost about $420 for fuel and $45 for the electricity to heat with a pellet stove, according to Stanley J. Raddon, vice president of Lignetics.