Traditional or conventional ovens basically have top and bottom elements. The bottom element heats to the selected temperature and the top element is used for grilling. In a conventional electric oven, the thermostat controls the heat in the middle of the oven so it is always slightly hotter in the middle. They take a while to reach cooking temperature so need to be pre-heated.
In addition to these main elements, multifunction ovens may also have a fan in the back wall, possibly a top perimeter element in addition to the grill, and/or a rear circular element. Multifunction or fan ovens circulate the heat around the oven creating a more even temperature. It also helps the oven heat up quicker which helps to save energy.
These ovens also enable you to switch fans and elements on and off to control where the heat is coming from, and to what degree, such as bottom heat only which is useful for making pies or pizza bases crisp, or top heat only, which is useful for browning food. Some also have rotisseries and a defrost setting which uses the fan.
With double ovens, often the main oven has a fan and the smaller oven is conventional although with top-end models, both models have a fan. Knowing how to use your multifunction oven will give you greater accuracy with your cooking.
Multifunction ovens use fans to move hot air around which helps speed cooking times. Because of this, there are a few guidelines to keep in mind when cooking in them.
Generally, cooking temperatures in recipes are designed for a conventional oven, that is, one without a fan. But if you're using an oven with a fan, or any of the fan settings on a multifunction oven, you'll need to reduce the temperature by 15-20°C to ensure your recipe doesn't cook too quickly or burn.
Fan ovens also cook food faster, so reduce the cooking time by 25%. And start checking for doneness 10 minutes before the food is scheduled to be done, and even sooner for foods that cook for long periods of time, such as roasts.
To understand all the multifunction oven settings, visit the Oven Settings page.