The report gives results of a 2-year study in Vermont and New York, monitoring woodstove performance. The objective of the study was to determine the effectiveness of catalytic and non-catalytic low-emission woodstove technology in reducing wood use, creosote accumulation, and particulate emissions. Wood use and creosote accumulation in chimney systems were measured in 68 houses over two heating seasons (1985-86 and 1986-87). Of these houses, 42 were instrumented to measure particulate emissions and wood use. Catalytic woodstoves, catalytic add-on/retrofit devices, and non-catalytic low-emission stoves were provided by various woodstove manufacturers for use by volunteer homeowners during the study period.