A double wall oven is one unit; it is not designed to be separated. If you are looking for a smaller oven or side-by-side installation, a single wall oven might be your best bet.
Both ovens in a double wall oven can be used at the same time, and they can be set to different temperatures. Having a double wall oven allows for the flexibility of cooking (or warming) two different things at once.
Because they’re designed to fit in with kitchen cabinets, double wall ovens are available in standard 24, 27 or 30-inch widths. Height may vary depending on the sizes of the ovens and the control panel.
Built-in wall ovens are self-contained and do not need to be vented to the outside.
Wolf, Thermador and Bosch all make popular models of double wall ovens, as do many other manufacturers. You can find dozens of models at Coast Appliances.