Built-in or slot-in?
Built-in
Ovens essentially come in two forms. The built-in oven will fit into a space among your kitchen cabinets, and will usually be placed well above the ground, so the upper shelves are at about eye-level.
Built-in ovens may be single ovens (with just one door, and one oven-space or 'cavity'), or double ovens (with two doors and two cavities). A double oven will offer a combination of features: the larger oven may, for example, be fan-assisted, and the smaller one a conventional oven, with a grill. The separation of these functions is important if you want, for instance, to bake one dish and grill another simultaneously.
Slot-in
Slot-in ovens, by contrast, are free-standing: they stand on the floor, often in a space between kitchen units. They usually include a hob (the set of rings that you use to heat pans on) above the oven, and the grill will either be below the hob, or at eye-level. The oven part will be at about knee-height, which means that you have to bend down to use it; this can be awkward when baking large dishes in heavy cookware, such as a cast-iron casserole.
Because of the height restriction, standard-size slot-ins are usually single ovens, but double or multiple ovens are available in wide models, such as the kitchen ranges.
Both built-in and slot-in ovens have their merits and drawbacks: your choice will depend on your personal preferences, your budget, and what your kitchen layout will permit.
