A convection oven (also known as a fan-assisted oven or simply a fan oven) is an

oven upA double oven A ceramic oven An oven is a tool which is used to expose materials to a hot environment. Ovens contain a hollow chamber and provide a means of heating the chamber in a controlled way. In use since antiquity, they have been use ...

that has fans to circulate air around food to create an evenly heated environment. The increased air circulation causes a fan-assisted oven to cook food faster than a conventional non-fan oven, which relies only on natural convection to circulate the hot air. Fan-assisted convection ovens are commonly used for baking as well as non-food, industrial applications. When cooking using a fan-assisted oven, the temperature is usually lower compared to that of a non-fan oven, often by , to avoid overcooking the outside of the food. In the context of ovens, the term "convection" is widely used to mean "fan-assisted", but this is perhaps not the most precise way to differentiate fan-assisted ovens from conventional ovens, since both types of oven cook using

convective heat transfer Convection (or convective heat transfer) is the transfer of heat from one place to another due to the movement of fluid. Although often discussed as a distinct method of heat transfer, convective heat transfer involves the combined processes o ...

(transfer of heat due to the bulk movement of hot air). Conventional ovens circulate hot air using

natural convection Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convec ...

and fan-assisted ovens circulate hot air using forced convection, so scientifically the term "convection" applies equally to both conventional (natural convection) ovens and fan-assisted (forced convection) ovens.

Culinary convection ovens

Convection ovens distribute heat evenly around the food, removing the blanket of cooler air that surrounds food when it is first placed in an oven and allowing food to cook more evenly in less time and at a lower temperature than in a conventional oven.

History

The first oven with a fan to circulate air was invented in 1914 but it was never launched commercially. The first convection oven in wide use was the Maxson Whirlwind Oven, invented in 1945.

Design

A convection oven has a fan with a

heating element A heating element converts electrical energy into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element. Unlike the Peltier effect, this process is indepen ...

around it. A small fan circulates the air in the cooking chamber. One effect of the fan is to reduce the thickness of the stationary thermal

boundary layer In physics and fluid mechanics, a boundary layer is the thin layer of fluid in the immediate vicinity of a bounding surface formed by the fluid flowing along the surface. The fluid's interaction with the wall induces a no-slip boundary cond ...

of cooler air that naturally forms around the food. The boundary layer acts as an insulator and slows the rate that the heat reaches the food. By moving the cool air (''convecting'' it) away from the food the layer is thinned, and cooking occurs faster. To prevent overcooking before the middle is cooked, the temperature is usually reduced by about . In addition, because the air gets well mixed, the oven has a very even temperature. Convection ovens may include radiant heat sources at the top and bottom of the oven, which improves heat transfer and speeds cooking from initial cold start. On the other hand, some ovens have all the heating elements placed in an outside enclosure and hidden from the food. This reduces the effect of radiant heat on the food; however, the walls of the oven will also be heated by the circulating hot air, and though the resulting temperature is much lower than that of a radiant heat source, it is still hot enough to provide some heating of the food by radiation from the walls.

Effectiveness

A convection oven allows 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, for example by an oversized

baking tray Baking is a method of preparing food that uses dry heat, typically in an oven, but can also be done in hot ashes, or on hot stones. The most common baked item is bread but many other types of foods can be baked. Heat is gradually transferred ...

. This difference in cooking temperature is offset as the 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, the temperature must be lowered to reduce the rate of heat transfer in order to compensate. Product testing of toaster ovens has demonstrated no notable advantages to convection cooking over conventional toasting or baking.

Variants

Another form of a convection oven is called an ''impingement oven''. This type of oven is often used to cook pizzas and lightly toast bread in restaurants, but it can also be used for other foods. 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. Impingement ovens can achieve a much higher heat transfer than a conventional oven, and fully enclosed models can also use dual magnetrons, like a microwave oven. The most notable manufacturer of this type of oven is Turbochef. The differences between an impingement oven (with magnetrons) and a convection microwave oven are cost, power consumption, and speed. Impingement ovens are designed to be used in restaurants, where speed is essential and power consumption and cost are less of a concern. There are also

convection microwave oven A microwave oven (commonly referred to as a microwave) is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces polar molecules in the food to rotate and produce ...

s which combine a convection oven with a

microwave oven A microwave oven (commonly referred to as a microwave) is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces polar molecules in the food to rotate and produce ...

to cook food with the speed of a microwave oven and the

browning Browning may refer to: Arts and entertainment * The Browning, an American electronicore band * ''Browning'', a set of variations by the composer William Byrd Places * Browning, Georgia, USA * Browning, Illinois, USA * Browning, Missouri, ...

ability of a convection oven. An

air fryer An air fryer is a small countertop convection oven designed to simulate deep frying without submerging the food in oil. A fan circulates hot air at high speed, producing a crisp layer via browning reactions such as the Maillard reaction. Some p ...

is a smaller countertop oven that also circulates hot air through the oven, but an air fryer uses a higher rate of air flow. A

combi steamer Combi steamers (also called combi-steamers, hot-air steamers, combination steam-convection ovens, or simply combi ovens) are cooking appliances typically used in professional catering or food service operations. Combi steamers can produce both dr ...

is an oven that combines convection functionality with

superheated steam Superheated steam is steam at a temperature higher than its vaporization point at the absolute pressure where the temperature is measured. Superheated steam can therefore cool (lose internal energy) by some amount, resulting in a lowering of ...

to cook foods even faster and retain more nutrients and moisture.

Industrial convection ovens

Industrial convection ovens can be very large-sized and are typically used for manufacturing various items. See hot air oven for ovens to sterilize medical equipment.