A convection oven (or fan-assist oven, fan oven) is an oven that imparts heat assisted by fans to force air movement, as opposed to a conventional oven, which relies on convective heat transfer unassisted by fans. By moving fast hot air past the food, convection ovens can operate at a lower temperature than a standard conventional oven and yet cook food more quickly. The air circulation, or convection, tends to eliminate "hot spots" and thus food may bake more evenly.A convection oven will have a reduction in cooking temperature, compared to a conventional oven. This comparison will vary, depending on factors including, for example, how much food is being cooked at once or if airflow is being restricted by using an oversized baking tray. This difference in cooking temperature is offset by the fact that circulating air transfers heat more quickly than still air of the same temperature; in order to transfer the same amount of heat in the same time, then, one must lower the temperature to reduce the rate of heat transfer to compensate.
Another form of a convection oven is the commercial impingement oven. This type of oven is often used to cook pizzas in restaurants. Impingement ovens have a high flow rate of hot air from both above and below the food. The air flow is directed onto food that usually passes through the oven on a conveyor belt. Air flow rates can range between 1 and 5 m³/s. Impingement ovens can achieve a much higher heat transfer than a conventional oven.
Like the "impingement oven", a convection oven usually has the radiant elements in view of the food, which improves heat transfer and speeds cooking from initial cold start. Some ovens have the heating elements placed in an outside enclosure and hidden from the food. This eliminates radiant heat from direct contact with the food.