Will prohibitive regs fire up wood burners?

Many people consider burning wood to be as American as apple pie, and now, with oil prices over $100 dollars per barrel, some are considering making wood their home’s primary source of heat.  Not everyone thinks that’s such a hot idea, however; opponents say wood-burning boilers cause excessive local pollution and serious health problems.

Outdoor wood boilers look like a small shed with a smokestack.  Typically, the boiler unit is located within 50 feet of the house it is heating.  Wood fired in the lower part of the unit heats water in the upper segment.  This water, piped underground to the house for central heating, is also able to heat the home’s water. 

One outdoor boiler can heat several structures, such as a barn or shop, in addition to the house; it can even heat a swimming pool or spa.  The devices, which range in price from $5,000 to $15,000, depending on size and quality, are simple in design and allow homeowners independence from utility companies and their spiking energy prices.  These qualities make them appealing investments for many.

Critics of the technology say the boilers are inefficient and unsafe.  They point out the low height of the smokestacks on the units; most local laws say that a smokestack must be higher than the roof of the tallest nearby building.  The stacks on outdoor wood boilers are usually between eight and 12 feet off the ground; this prevents the smoke from dissipating and causes it to hang around at ground level during cold-air inversions. 

The burning inefficiency of the boilers constitutes the bulk of the problems their owners encounter, says Tom Todd, of the Washington State Department of Ecology.  Requiring manufacturers of outdoor wood boiler systems to design more efficient and environmentally-friendly boiler units would help solve the problem.

“Their thermal efficiency sucks,” Todd said during a phone interview. “Basically, when you heat something up, that heat needs to be held somewhere, or you just lose it and have to expend more energy to get it hot again.”

Indoor wood-burning stoves and fireplace inserts are required to operate at a certain level of efficiency.  When the Federal Environmental Protection Agency passed these regulations in the late-1980s, it exempted things such as fireplaces and outdoor cooking fires.  This allowed manufacturers to sell outdoor wood boilers without designing them to conform to the same emissions standards as wood-burning stoves. 

“They’re primitive,” said Todd, of the outdoor boilers.  “The efficiency on them is between 28 and 55 percent; on average they are around 43 percent, compared with a modern woodstove, which operates between 68 and 72 percent efficient. “ 

Outdoor wood boilers are effectively banned in Washington because the state requires a wood-burning stove to be certified through a test that requires four modes of operation, as is common for indoor wood stoves.

“In the testing method we have, we require multiple test rates, and these suckers only have off and on,” said Todd.  Although it is a regulatory loophole, Todd said he didn’t think outdoor wood boilers would ever be efficient enough to pass regulatory standards.

Outdoor wood boilers usually have only two modes of operation: on and off.  The stoves are designed to switch into “idle” mode when the water reaches a pre-set high temperature, at which point the damper closes and the wood smolders in the unit. 

This cool-burning and inefficient fire causes carcinogen-laden creosote to accumulate on the interior of the unit.  When the water temperature reaches a pre-set low, the damper opens and the machine “belches creosote for 10 minutes” until it reaches normal levels of smoke, according to Todd.

Efficient boilers

“Some people modify them, and that helps a lot,” said Todd.  “One heating engineer lined his with thermal bricks and installed baffles to increase the distance the smoke had to travel to get to the stack and he was able to cut back on emissions significantly.”  Thermal bricks work to retain the heat and increase the time between the unit idling and re-igniting, he said.

The makers of Alternative Fuel Boilers’ line of wood-fired systems, Econoburn Gasification Boilers, declare their highly efficient boilers “90 percent efficient.”  The company’s system uses a secondary chamber to burn the combustible gases released by the wood; most other wood boilers send these gases up the flue.

Econoburn boilers meet Energy Star specifications; the cooperative program of the Environmental Protection Agency and the United States Department of Energy serves to promote efficient and environmentally friendly building products.  The highly efficient boilers also use a “ceramic heat refractory” which, like the engineer’s thermal bricks, serves to decrease the rate at which the water cools, lengthening the time between firings. 

The secondary chamber operates even when the unit is idling, burning up the gases and increasing efficiency while decreasing pollution.  According to the company’s website, www.alternativefuelboilers.com, customers may be eligible for state or federal tax rebates; the website also claims that Econoburn boilers, which operate at around 90 percent efficiency, are more efficient than natural gas, which averages 78 percent efficiency.

Other wood-burners

Wayne Stritsman, the owner and operator of Best Fire Hearth and Patio in Cobleskill, started his company in 1977.  He said the oil shortages of that time caused the interest in burning wood that prompted him to start his business.  He warns consumers against the outdoor wood boiler.

“Be very careful before investing in one of these outdoor wood boilers, because if not today, they are going to be outlawed tomorrow, and you will lose your money, and it is due to the environmental pollution,” he said.

Five residential outdoor boiler systems in Albany County have been shut down, Stritsman said; the New York State Department of Environmental Conversation’s code makes an outdoor boiler system subject to commercial emissions standards and the department is using that code to shut down the home boilers.  He believes that environmental regulations will eventually prohibit the use the outdoor systems altogether. 

 “I don’t think it is the right way to go, not ecologically, not in terms of efficiency or cost-effectiveness,” said Stritsman. 

Best Fire sells wood-burning appliances; just not the outdoor boiler variety.  The Cobleskill-based company sells fireplaces and inserts, as well as more sophisticated pellet-burning stoves, boilers, and fireplaces. 

The pellets, made from compressed lumber by-products, cost far less than oil or natural gas.  They are fed into the stove or furnace by an electronically-controlled hopper so there is less tending and owners can leave for several days at a time and not worry about returning to pipes burst from freezing.  The stoves are typically used to heat several rooms rather than the entire house.  Pellets cost $225 per ton, while fuel oil costs $500 for 125 gallons; wood pellets are therefore currently half as costly as fuel oil.

 “The Europeans have learned to use space heaters, because there is no reason to heat the entire house if you aren’t using the entire house.  Central heat is a luxury and space heating is more the norm in Europe,” said Stritsman.

A consumer looking to heat their homes with wood have many options, and while the notion of the outdoor boiler is appealing, it is not always practical, especially if you have neighbors who will be affected.  Unless the property to be heated is in a very rural area and includes outbuildings such as shops or garages that must also be heated, outdoor wood boilers may not be the best bet.