Single or double cavity built-in ovens are available to build into or under kitchen units. The choice is between built-in to a cabinet at a higher level or built-under which means underneath the work surface. Double cavity ovens can have either 2 main fan ovens, or one main oven and a seperate cavity for grilling only. Make sure you check this when doing your research.
After this the main decision is whether to have a single or double oven. Some double built in ovens have only one real oven, the second being a cavity with a grill. Here is some more information on features of built in ovens:
Conventional ovens can be gas or electric. In a conventional gas oven, the heat comes from the gas burner at the rear bottom of the oven. In a conventional electric oven, the heat comes from elements under the base and at the top of the oven. In a conventional oven, heat rises to give a hotter temperature towards the top of the oven, and a slightly cooler temperature towards the bottom of the oven. The heat zones in a conventional oven make it ideal for cooking a number of dishes together, where different cooking temperatures are required. Conventional ovens are perfect for traditional cooking for things like cakes and roast meat.
Electric grills consist of either single or dual elements, and may have fixed or variable heat settings, depending on the model. The heat output of variable grills can be controlled by turning up or down, between low heat and high heat settings.
A fan assisted oven has an even cooking temperature throughout the oven as the fan circulates the heat. This makes it perfect for batch baking. Heat comes from the element in the back of the cavity, beit in the middle or top of the oven, and the hot air is circulated around the oven cavity so that an even cooking temperature is achieved throughout the whole of the oven.
A multifunction oven is an electric oven which has many cooking functions. These functions will include a selection of the following; fanned oven cooking, conventional oven cooking, grill, fanned grilling, base heat only, top heat only, fan plus base heat, intensive bake and defrost.
The main manufacturers of built-in ovens are Neff, Bosch, Siemens, Whirlpool, AEG, Zanussi, Smeg, and Baumatic. Look at for the warranty periods, 2 years is really the minimum you should expect now, and some manufacturers like De-Dietrich and Fagor offer 5 years as standard on various models.
Colous and trims are usually stainless steel and black, but the more traditional white and black remain popular. Stay clean liners are a feature many cooks don't ever want to live without - they help burn away the excess food that sticks to the sides and top of the oven. This is by using a certain kind of catalytic material that lets the food evaproate or burn, leaving a residue that can be wiped away.
Installation should be via a qualified electrician, although some basic conventional ovens are 13 amps and can be plugged straight in to the mains. Please take advise before fitting your new oven.