The Environmental Protection Agency (EPA) has toughened emission requirements for residential wood heaters, and for the first time the rules will cover indoor and outdoor boilers, forced-air furnaces and pellet stoves.
Final rules issued on Feb. 3 will be phased in over a period of time, and they don’t affect wood stoves that people already have.
The agency said the more stringent requirements, made possible by better technology, would reduce emissions of fine particulates and volatile organic compounds by nearly 70%.
The number of U.S. households using wood as the main source of heat is tiny–a total of only 2.5 million, according to the U.S. Energy Information Administration (EIA), with another 9-million households using wood as a secondary heating fuel. But those numbers grew as the price of fossil fuels rose, particularly in New England.
The EIA reports the use of wood as a main source of heat was up by more than 100% in all six states in the region between 2005 and 2012, while showing growth of greater than 50% in a handful of other states.
Existing emissions requirements for wood heaters were issued in 1988, according to the EPA’s fact sheet, and covered “adjustable burn-rate wood stoves” and fireplace inserts. “Since that time,” the agency says, “the technology for reducing emissions from wood heaters has significantly improved and is now available to make a range of wood heaters more efficient and less polluting.”
Addressing a “significant national air pollution problem”
The smell of wood smoke on the cold night air is familiar and pleasing to many country-dwellers in the north, but wood smoke is actually a serious air pollutant, the EPA says, and a particular health threat to older people, children, and those with heart or lung disease.
Wood-fired heaters dump hundreds of thousands of tons of fine particulates into the air, and smoke from residential sources causes “many counties” in the country to exceed EPA air-quality standards.
“In places such as Keene, N.H.; Sacramento, Calif.; Tacoma, Wash.; and Fairbanks, Alaska,” the EPA says, “wood combustion can contribute over 50% of daily wintertime fine particulate emissions.”
The agency estimated the monetary benefits of the new rules at $3.4 billion to $7.6 billion a year, with annual costs of $46 million, meaning that for every dollar spent to comply there would be benefits of $74 to $165 in the way of avoiding health problems such as asthma and nonfatal heart attacks, emergency room visits for respiratory problems, lost work time, and premature death.
New limits represent a steep drop
Under emission rules approved in 1988, wood stoves with catalytic combusters (similar to the catalytic converters on a car exhaust) were limited to 4.1 grams of particulates per hour; noncatalytic stoves were limited to 7.5 grams per hour.
The new rules for wood stoves would come in two steps. In the first phase, 60 days after the final rule is published in the Federal Register, stoves without current EPA certification could produce no more than 4.5 grams of particulates per hour of operation. Five years after the effective date of the rule, all wood stoves and pellet stoves could emit no more than 2 or 2.5 grams per hour, depending on the test method.
For wood-fired wood furnaces, emissions would have to fall to 0.93 lb. of particulate emissions per million Btu of heat output within a year or two (depending on the size of the unit) and then to 0.15 lb. per million Btu lb. by 2020 for all furnaces.
Finally, wood-fired boilers would be limited to 0.32 lb. of particulates per million Btu 60 days after the rule takes effect, and 0.10 lb. by 2020.
EPA’s new rules are “fair”
The Alliance for Green Heat, which advocates the use of wood as a renewable fuel, said it lobbied for regulations that were “pro-consumer,” ones that would result in cleaner-burning stoves that were still affordable. And by and large, the group said it was pleased with EPA’s final rule.
“Overall, the EPA did a good job and released a fair rule that includes many compromises between industry and air-quality agencies,” a blog at the organization’s website says. “We think these rules are good for consumers and will not drive prices up substantially for most product categories, but will result in cleaner and more efficient appliances that will ultimately save consumers time and money.”
The group said it was disappointed with a few provisions, including the delay in imposing standards for all forced-air furnaces, but on the whole found the rules “fair and balanced.”
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New emissions standards for wood stoves, boilers, and furnaces will limit the amount of fine particulates they produce. The overhaul of existing rules was announced earlier this month by the Environmental Protection Agency.
