The paper discusses data and preliminary findings from the first year of a 2-year detailed evaluation of woodstove performance characteristics under field conditions that was conducted on 32 volunteer houses in New York State and Vermont. Woodstoves were monitored for particulate emissions, wood fuel use, and creosote accumulation in the chimney. Comparisons were made between stove technologies represented in the study houses: catalytic, high-efficiency noncatalytic, and conventional stoves. Add-on/retrofit catalytic devices added to conventional stoves were also evaluated. Field results showed that catalytic stoves achieved emission reductions of about 25%, compared to conventional stoves. Prior laboratory tests on the same catalytic stove models indicated reductions of 5 to 10 times were possible. High-efficiency noncatalytic technology, based on very limited data, showed the lowest average emission rates. Add-on/retrofit devices showed no emission reduction.