21 in combination the exterior of secondary combustion chamber 50 and wall 21 define a secondary air chamber 70 at the bottom of wall 21 is attached directing plate 22 directing plate 22 has an inlet aperture 23a which connects woodbox area 30 with secondary combustion chamber 50 directing plate 22 in combination with fire brick wall 17 also define apertures 23b and 23c which connect secondary combustion chamber 50 with secondary air chamber 70 directing plate 22 has a nozzle shape such that the inlet passageway 24a between woodbox area 30 and secondary combustion chamber 50 narrows as it extends towards aperture 23a inlet passageways 24b and 24c also narrow as they extend towards secondary combustion chamber 50 such narrowing is preferred to accelerate gas flow and aid secondary combustion in the exemplary embodiment the narrowest point of such passageways does not exceed two inches in width in operation entrance of air into stove 10 is through primary air duct 31 and secondary air duct 32 air ducts 31 and 32 have butterfly valves 31a and 32a respectively to control the rate of airflow into stove 10 these ducts communicate directly with the outside of the building b in which woodburning stove 10 is located primary air duct 31 leads into primary air chamber 80 apertures 33a and 33b allow fresh air to flow directly beneath grate 16 from the primary air chamber 80 during combustion the fresh air rises through grate 16 and into primary combustion area 20 where it mixes with burning wood exhaust from the fire.