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Woodburning 101 

Smoke from wood burning stoves contain tiny particles that are so small the body's natural defenses can't prevent them from lodging deep into lungs. These tiny particles can damage and change the structure of lung tissue and can carry harmful toxins directly to the bloodstream. This can lead to serious respiratory problems, asthma attacks, heart problems and even premature death.

Certified woodstoves burn cleaner

Oregon was first in the nation to require new certified woodstoves to meet air pollution standards and all new stoves are required to be certified by the Environmental Protection Agency. You can tell if your stove is certified by looking on the back for a certification sticker from Oregon DEQ or EPA. Woodstoves that are not certified waste up to 60% of the wood burned in them. Certified stoves are much less polluting than older, non-certified stoves, reducing fine particles by 70%. Pellet stoves and oil or gas furnaces or stoves are even cleaner than certified stoves.

Replace your woodstove and save money

If you own an old, inefficient stove, replacing it with a newer, cleaner heating system will pay for itself through fuel savings. Alternative stoves include natural gas stoves and furnaces, EPA certified woodstoves and pellet stoves.

The Oregon Department of Energy has a tax credit of up to $300 available for homeowners who purchase a premium efficiency woodstove or pellet stove. In addition, there is a federal tax credit of up to $1500 available for the purchase of an efficient wood burning device. This applies to devices purchased between January 1, 2009 through December 31, 2010.

There are two kinds of approved wood burning stoves: "catalytic” stoves and "non-catalytic" stoves. Catalytic stoves use a ceramic catalyst inside the firebox to assist with the burning of waste-gases (smoke). Non-catalytic stoves use a combination of sophisticated baffles and air supply designs to burn waste gasses efficiently. In general, catalytic stoves are a little more efficient initially than non-catalytic stoves, but catalysts deteriorate over time and need to be replaced every 2-4 years to ensure good performance.

Wood burning tips

  • Burn only wood. No garbage, plastics, rubber, paint or oil, briquettes, paper, etc. Burning these items releases harmful chemicals into the air.
  • Burn Wise Program from EPA: Emphasizes the importance of burning the right wood.
  • Build small, hot fires instead of large, smoldering ones.
  • Don't "bed the fire down" for the night. Holding a fire overnight is a fire hazard and can create serious indoor and outdoor air pollution problems.
  • Open your damper if the smoke is dark. Dark smoke indicates more pollution is being produced and fuel is being wasted.
  • Keep your stove clean and well-maintained. Follow manufacturer guidelines; replace catalytic stove filters every 1-4 years. Have your chimney checked and cleaned at least once a year.

Use seasoned wood

The best fuel for woodstoves is dry, "seasoned" wood. Seasoned wood has a moisture content of about 20% or less. It tends to be dark in color, cracked on the ends, light in weight and has bark that is easily broken or peeled. Here are some tips for preparing seasoned wood:

  • Split the wood to help it dry. Wood will dry out more quickly and burn best if the wood is cut to about 3 1/2 inches to 6 inches in diameter.
  • Cover the split firewood to protect it from the weather and stack it loosely in alternating layers, at least 6 inches off the ground.
  • Time must be given to allow the wood to reach 20% or less moisture required for seasoned wood. This process takes approximately 6-12 months. Think ahead and buy next winter's wood well in advance.

Guidelines for Preparing Seasoned Wood

Species Minimum Outdoor
Drying Time
Heating Value
Million Btu per Air-Dried Cord
Ease of Splitting Sparks
Alder Longer than 6 months 18-21 medium easy moderate
Cedar 6 months 14-20 medium-low easy many
Douglas Fir 6 months 19-21 medium easy moderate
Madrone 6 months 30 high difficult very few
Maple 6 months 19-21 high-medium moderate few
Oak 6 months 29-31 high moderate few
Pine 6 months 17 medium-low easy moderate
White Fir 6 months 17 medium-low easy moderate

Consider "carbon-neutral" firelogs for fireplaces

Manufactured firelogs are pre-packaged fuel for fireplaces usually made from recycled sawdust and wax. Firelogs are a user-friendly solution for building a fire in a fireplace and are a significantly cleaner burning alternative to using firewood. Resource-efficient firelogs made with 100% renewable resources, instead of petroleum, are now available for a "carbon-neutral" fire. Firelogs produce approximately 70% less toxic air pollution than firewood They produce significantly less carbon monoxide and creosote as compared to firewood Firelogs burn between 2-4 hours depending on the size.*

Maintenance tips

Each year there are numerous Oregon home and chimney fires caused by wood burning. Periodic inspection of your stove or fireplace is essential to its continued safe and clean-burning operation. The Oregon Chimney Sweep Association recommends an annual chimney cleaning to remove creosote build up and to identify potential problems. Things to consider:

  • The Chimney cap may be plugged by debris.
  • Catalytic combustor and baffles are exposed to very high heat and deteriorate as used. Replace every 1-4 years depending on use.
  • Stovepipe angles and bolts are subject to corrosion.
  • Gaskets on airtight stove doors need replacement every few years. Gaskets and seals are used by the appliance designer to control the location and flow of air into the appliance.
  • Check seams on stoves sealed with furnace cement. Seams may leak and cause you to loose valuable heat and reduce the efficiency of the unit.
  • Replace broken or missing firebricks.
  • Keep the floor of your stove clean of debris and ash.

*Source: Environment Canada and US EPA - Region 5, Content and emission characteristics of Artificial Wax Firelogs, May 2006

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For more information about Air Quality call 503-229-5359 or email.


Oregon Department of Environmental Quality
Headquarters: 811 SW Sixth Ave., Portland, OR 97204-1390
Phone: 503-229-5696 or toll free in Oregon 1-800-452-4011
Oregon Telecommunications Relay Service: 1-800-735-2900  FAX: 503-229-6124

The Oregon Department of Environmental Quality is a regulatory agency authorized to protect Oregon's environment by
the State of Oregon and the Environmental Protection Agency.

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