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New Hampshire Department of Environmental Services


Woodstoves, pellet stoves, wood-fired hydronic heaters, and forced air furnaces are examples of residential wood heaters. Smoke from residential wood heaters contains emissions of fine particle matter, carbon monoxide, and other organic compounds, such as formaldehyde, benzene, and aromatic hydrocarbons, which form from incomplete combustion. The fine particulates of wood smoke, ten microns or less in diameter (a human hair is approximately 70 microns in diameter), can be inhaled deep into the lungs, collect in tiny air sacs (called alveoli) where oxygen enters the blood, and cause breathing difficulties and sometimes permanent lung damage.

Wood smoke is a particular concern in the winter, when cold stagnant air and temperature inversions limit air movement. Smoldering fires and short chimneys may create heavy smoke close to the ground that sometimes causes a neighborhood nuisance or an adverse impact on public health and the environment.

Fortunately, recent advances in wood heater design have resulted in the manufacturing of cleaner-burning units. The use of these cleaner-burning units, in conjunction with best management practices, can reduce and minimize any adverse health and environmental impacts associated with using these devices.

Burning Efficiently

You can reduce the amount of smoke from residential wood heaters by choosing low-emission units certified by the United States Environmental Protection Agency (USEPA); see Regulations below. Proper operation improves combustion efficiency, reduces emissions, helps protect public health and the environment, and saves fuel costs. You must also:

  • Follow manufacturer requirements for installation and operation of your specific wood heater.
  • Burn only dry, seasoned wood. Avoid burning wet, rotted, diseased, or moldy wood. Do not burn household garbage, pressure treated wood, painted wood, plywood, oil or chemical stained wood, or wood glued or treated in any way. It is against the law!
  • Conduct routine maintenance to keep the wood heater operating at its peak efficiency. The USEPA and fire officials recommend that your wood heater, chimney, and vents be professionally inspected and cleaned each year to keep them in safe working order.


On February 3, 2015, the USEPA finalized its New Source Performance Standards (NSPS) for emissions from residential wood heaters. These new emission standards reflect the significantly improved technology available to manufacturers to make cleaner burning and more efficient wood heaters. They will provide important health benefits to communities across the country and build on the work that manufacturers, states and local communities have done to improve air quality.

As of January 1, 2016, only USEPA-certified residential wood heaters that meet the requirement of this rule can be legally sold in the United States. Wood-fired forced-air furnaces must also meet requirements based on their size by either March 2016 (small units) or March 2017 (large units).  In addition, all wood heaters must have a permanent label indicating they are USEPA-certified to meet emission limits in the rule. This label will signal to consumers that the heater meets USEPA standards. The New Hampshire Department of Environmental Services will assist the USEPA in conducting outreach, education, and enforcement of this new law.

NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
(603) 271-3503 | TDD Access: Relay NH 1-800-735-2964 | Hours: M-F, 8am-4pm

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