Bosch introduced this feature with their Serie 8 ovens. This allows their ovens to bake food evenly, despite being placed on up to four different levels! Anyone who is a fan of baking knows that it is difficult to get the same consistency for your baked goods if you are baking on different oven shelves.
How does it work?
Their specially designed fan wheel will change its direction of spin at regular intervals. This distributes hot air more evenly around the oven.
Do I really need this feature?
If your baking only requires a single shelf, or you enjoy the inconsistencies in your baked goods, then no you really shouldn’t consider this feature. However, if you bake using multiple shelves (such as two or more pizzas, or multiple trays of muffins, cookies, and/or cupcakes) and you’d rather turn the oven on and wait for the alarm to sound, then yes, you most certainly should consider getting an oven with 4D Hot Air.