An oven with air convection combustion, particularly for bakehouses (bread, pastries, cakes), to achieve considerable economy of energy and to improve efficiency has primary and secondary air circuits sealed and closed, the secondary air being heated in ducts surrounding the fire-box and exhaust conduits and admitted into the baking chamber through adjustable nozzles. The cooled secondary air leaving oven is recycled by the a turbine. A vapor generator is formed from metal tubes extending into the exhaust gas conduit and the vapor is fed to a ramp pierced with calibrated holes disposed vertically in the baking chamber through which it is disposed into the chamber after being saturated by a water injector.