Do Vertical Ducts for Range Hoods Have to Go Through the Roof?

Roof Venting

• Many range hoods that use vertical ducts vent through the roof. This system relies on hot air's natural tendency to rise. A fan may help collect air near the cooking area, but additional fans aren't needed to cause the air to rise up and out of the home. With hot air leaving the kitchen, cooking doesn't warm the room as much as it would otherwise, making it more comfortable to work or dine in.

Wall Venting

• In some cases the vertical ducts for range goods take diagonal courses and vent through an exterior wall. This is an efficient option if your oven or cooktop is set against an exterior wall. This type of venting has the same benefits as a vertical duct that allows air out through the roof. Venting through the wall may also require less ductwork, especially in a two-story house.

Recirculating Hoods

• Some range hoods don't remove hot air from the kitchen at all. Recirculating hoods have fans and short vertical ducts that allow air to rise a short distance before being blown back into the kitchen. Since warm air rises, this air generally collects around the ceiling, with the range hood's fans expelling it upward. A recirculating hood requires little ductwork and is easy to install but allows a kitchen to get warm easily whenever the stove is on.

Downdraft Venting

• Another type of vertical range venting system is a downdraft vent. This type of vent uses fans to draw hot cooking air downward, through ducts that run behind the oven or cabinets. Downdraft vents expel air near the kitchen's baseboards, not removing it from the room but allowing it to cool as it circulates through the duct and keeping the cooking area at a manageable temperature without the need for any ductwork above the range.