Clearing the air. By 1988, wood stoves redesigned to meet EPA standards will be cleaner, safer, and much more efficient

When the wood-burning revolution of the early '70s was at its height, Richard Russo was short of money and out of work. So he did what hundreds of others with metal fabricating skills were doing at the time: he started building stoves. They were simple black boxes with a baffle that put out a lot of heat - and a lot of smoke as well. Today, those early stoves are on their way out, already banned for new installations in two states, Oregon and Colorado, and from the entire United States after proposed EPA standards for wood stove emissions become law in 1988.

To Mr. Russo, this is no cause for alarm. He feels regulating emissions will do for the wood-stove industry what they did for the auto industry - bring about a much better product.

Already, a second wood-burning revolution is well underway, this time a technological one that promises to clean up American skies, boost wood-burning efficiency, and virtually eliminate the chances of chimney fires in those homes using the advanced stoves.

Carter Keithly, executive secretary for the Wood-burners Alliance, believes the new trends will force many companies out of the stove manufacturing business. More will get out than stay in, he feels, because the research and development costs for the new clean-burning models can range ``anywhere from $40,000 to upwards of half a million.'' Under these circumstance ``only those really committed to wood burning will stay in,'' he says.

Mike Stilman is vice president of Consolidated Dutchwest, the largest mail-order manufacturer of wood stoves in the US. As he sees it, the new standards will hasten what was inevitable.

``If the television industry has only a handful of manufacturers when virtually every American home boasts at least one television set, how can the wood stove industry support several hundred manufacturers when only one in 40 US homes has a wood-burning stove?'' he asks.

Smoke pollution first became a noticeable American problem in Oregon, Colorado, Utah, Vermont, and other mountainous regions. On still, windless winter days, smoke stays trapped in the valleys, throwing a pall over rural areas that was once a common sight only in manufacturing towns during the Industrial Revolution.

The old-time unregulated stoves, including the long-burning air-tights, frequently put out 30 to 40 grams of particulates (pollution) an hour. By contrast, the EPA regulations , which follow Oregon and Colorado's lead for 1988, allow four grams of particulate matter an hour from a flue on all stoves equipped with a catalytic combustor. By 1990 that figure will drop to three grams an hour.

A catalytic combuster cleans up wood-stove emissions in much the same way a catalytic converter works on auto exhaust.

Russo's latest catalytic stove has been tested and certified at 1.9 grams an hour. Mr. Stilman says that six out of the eight Consolidated Dutchwest models already meet the 1990 standards, and bringing the remaining two into line will present no problems. Vermont Casting's latest stove, the Defiant Encore, has just been certified at under one gram an hour.

Clean-burning, non-catalytic stoves have also been developed. EPA standards - 8 grams an hour - are somewhat less stringent for these. But the nature of smoke-burning, non-catalytic technology is such that it is only possible to build small stoves at present. They are best used as single-room heaters rather than whole-house heaters. For this reason most people in the industry believe catalytic combusters will dominate clean-burning technology for the forseeable future.

The EPA's insistence on cleaner air will add from $150 to $300 to the price of a wood stove. But the increased cost will be more than recouped over the lifetime of the stove. By burning the smoke, you effectively increase the fuel value of your cordwood by 50 percent. That means that two cords of wood in a high-tech stove can do the same as three in one of the older versions. Just as significantly, you get a longer burn time from each load of fuel, which means you don't have to feed the stove so often.

But perhaps the best reason of all for including a stove with catalytic combustion in your home is the reduction of creosote (sooty tar) on the inside walls of your chimney. When properly operated, a catalytic combuster reduces creosote, the cause of all chimney fires, by a whopping 90 percent.

``Never mind the economics, safety is the most important contribution to come from the catalytic combuster,'' Stilman insists. Russo agrees, saying that before putting one of his newer stoves in his lakeside cabin, he cleaned five gallons of creosote out of the chimney every year. ``Now, every other year I get just enough to fill a gallon paint can.''

Using a catalytic stove is not difficult, but it is different. You can't simply ``light up and walk away,'' as Stilman puts it. There is a period between starting the stove and smoke temperatures becoming hot enough to activate the catalyst. Initially, the smoke is routed around the catalyst until a temperature probe indicates that the minimum temperature of 500 degrees F. is reached, at which stage the bypass damper is released and the smoke then starts passing through the combuster.

This period to ``light up,'' as it is termed in the trade, can vary from a few minutes to perhaps 15 minutes, depending on the stove and the size of the fuel being used. Big logs take a while, kindling on the other hand takes barely a minute to reach the required temperature. When reloading, it is important to open the bypass damper to avoid any possibility of smoke being drawn back into the room. Also, check the temperature again before reengaging the catalyst as a heavy load of fuel can temporarily lower it to below the light-up point.

It is important, too, to burn only natural wood and the black-ink pages of newspaper (but not glossy magazines). Just as leaded gasoline can destroy the auto exhaust catalyst, so contaminants in a wood fire can poison the catalyst. Don't throw painted wood on the fire or wood containing galvanized nails. Treated wood (against termites and rot) will also degrade the catalyst, as will aluminum foil.

The ceramic catalyst won't suddenly break down and stop working like a stalled car. But it does slowly lose its efficiency. Experience shows that most catalysts last between four and six years, at which stage they are about 70 percent efficient. Replacing the catalyst currently costs about $100.

Will a stove owner replace the catalyst regularly? ``Yes,'' says Russo. ``It's in his economic interest to do so. Say the catalyst lasts five years. That means it's costing $20 a year. Catalysts easily save wood burners a cord of wood a year. Where can you buy a cord of wood for $20 these days!?''