EPA regulates wood stoves with a firebox volume of less than 20 cubic feet, an air to fuel ratio of less than 35 to 1, a burn rate of less than 5 kg/hr and a total weight of less than 800.
The New Source Performance Standard for Residential Wood Heaters (40 CFR Part 60 Subpart AAA) was promulgated in 1988 as part of a regulatory negotiation process with the hearth industry and non-governmental organizations to reduce particulate emissions from wood stoves. The wood heater regulation requires wood stove manufacturers to undergo emissions testing at an EPA-accredited laboratory to certify that each wood stove model line complies with the particulate emission limit of 7.5 grams/hour for non-catalytic wood stoves and 4.1 grams/hour for catalytic wood stoves. The rule also requires manufacturers to conduct a quality assurance program for production-line wood heaters and to certify by a permanent label that each wood heater meets the applicable emission standard. A temporary label is also required for use by the consumer, that specifies the emission rate, the heating range of the wood heater and overall efficiency.
The EPA regulations are available at this link: http://www.epa.gov/compliance/resources/policies/monitoring/caa/woodstoverule.pdf
The EPA is planning to proposed revisions to the wood heater regulations to further reduce particulate matter pollution. Stay tuned for more details.
The EPA document, Strategies for Reducing Residential Wood Smoke, is available at http://www.epa.gov/burnwise/pdfs/strategies.pdf.