A convection oven is more efficient than a standard oven, cooking food quicker and more evenly. The fan-circulated air heats the oven quicker and avoids the hot and cold spots that can occur in ovens without this added circulation.
In a traditional oven, the heating element warms the air near the bottom of the oven, which rises and fills the space with heat. A convection oven adds a fan to this system, circulating the air throughout the oven. This spreads the heat quickly and evenly, reducing pre-heat times. As long as there is plenty of room around the food being cooked, the convection oven cooks more efficiently.
The benefits of a convection oven are particularly apparent when baking. Most baking recipes call for cooks to turn pans at least once during the cooking process to evenly distribute heat and prevent overdone and underdone spots. Unfortunately, this entails opening the door and letting out the accumulated heat, increasing cooking time. The circulation of a convection oven keeps these warm and cold spots from occurring, so there is no need to waste heat and time by opening the oven door.
Switching from a traditional oven to a convection oven does require some adjustment. Following a recipe designed for a traditional oven often results in overdone food in a convection oven. Cooks should begin by reducing the temperature by 25 degrees or the cooking time by around 25 percent to prevent burning.