A downdraft range is a kitchen range that vents smoke and odors down, rather than upward like a traditional oven top range does. A downdraft exhaust system pulls air down through a tube and out of a vent in the side of the house.
Downdraft exhaust systems are more common when the kitchen stovetop is in an island that does not have a hood exhaust system going up through the roof. The advantage of a downdraft system is that it removes the obstruction of a range hood in the middle of the kitchen. The disadvantage is that an updraft system is more effective for removing odor.