A convection oven (also known as a fan-assisted oven or simply a fan oven) is an oven that has fans to circulate air around food. Conventional ovens, which do not have fans, rely primarily on radiation from the oven walls, and to a lesser extent, on natural convection caused by temperature differences within the oven, to transfer heat to food. In contrast, the fans in convection ovens allow more heat to be transferred via convective heat transfer.