We recently purchased a new construction home. The original kitchen plan came with a slide-in range with a microwave above, vented between the studs behind the microwave and up through the roof. We upgraded to the “gourmet” option which allowed us to have a separate cooktop, microwave/oven combo unit, and a vent hood. We chose a pull-out vent hood that is mostly hidden in the cabinet above the cooktop. I chose a hood that could be vented to the top or to the back. I expected the hood to be vented to the back and connected to the vent in the wall between the studs in the same manner as when the builder uses a microwave to do the venting. 138BET