Jenn-Air manufactures a gas downdraft range; as of March 2012, it was the only company that still produced one. Gas downdraft ranges contain an integral blower inside the range that vents the smoke, grease and heat down and outside through the ductwork. These ranges therefore require no additional vents.
Jenn-Air manufactures one model of gas downdraft range, which is 30 inches wide and features a burner rated at 15,000 British thermal units. The range has an efficient convection system that evenly distributes heat, and it comes in black, white or stainless steel.
Downdraft ranges have several disadvantages; the blowers are not strong enough to handle a high volume of cooking and they are not very efficient as they do not capture air very well.