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Venting a range hood down thru the basement

17K views 9 replies 5 participants last post by  beenthere  
#1 ·
I know this topic has been raised before, but each person's situation is different, so I thought I would sketch out mine and ask the GardenWeb community for advice and insights.

Our typical Whirlpool gas range sits in our condo's kitchen against a 4" interior wall. There's a microwave above the stove with a recirculating fan system that speeds up the time it takes to stink up the place every time I do a stir fry or sautee some onions. I would like to replace the microwave with an under-cabinet range hood, but there is no reasonable way to run venting to the roof (there's a small office above the kitchen) or an exterior wall, given the direction of the studs in the ceiling.

I removed the microwave the other day and could see an installed piece of 3.25x10" ducting in the wall behind it. The duct's opening faced the kitchen, then did an abrupt 90 degree turn downward, continuing down between the wall studs maybe 7 or 8 feet to end abruptly high on the basement wall, right where it meets the ceiling.

I am thinking about buying a range hood with a 3.25x10" opening in the back of the hood that I can connect to the existing vent, which I can move around a bit to line up with the hood. I would then use an adapter to connect to the duct in the basement, angling downward about 20 degrees, while transitioning to an 8-inch round duct. That duct would continue about 10 feet to the sill of the building, where I'd exhaust it.

To power the system, I would avoid buying a fan blower for the hood, since that would just blow the air directly into the duct's initial 90-degree bend, creating a lot of back pressure. Instead, I'm thinking of installing an inline 600 cfm blower, which would hang from the basement ceiling somewhere along the 10-foot stretch of 8" round duct. If that's not powerful enough, I could also use a 900 or 1100 CFL blower. The fan comes in a housing so it's easy to connect the round ducting to it.

Thus, the inline fan would suck air down the wall duct, rather than try to push the air down.

Do you think this approach would work? I'm wondering if applying 600 cfm suction to a 3.25x10" vent would create a lot of noise and/or provide good suction within the hood. I should add that the hood I'm looking at has an adjustable knob that lets you infinitely adjust the fan speed, so I could reduce the suction if the noise were too extreme.

Your help is always appreciated!
 
#2 ·
Not going to work or at least well. They do make down draft vents that mount in the counter behind a cooktop. They are commonly used on islands. I am not sure how this might work in your instance, but I think I would start down that track rather than try to adapt a standard range hood.
 
#7 ·
Yes, the inline fan is designed to be a remote blower for range hoods. Like the hood, it's made by a company called BEST (very original name!), a subsidiary of Broan. It will exhaust out our home's sill-- i.e., the wood stud that lies in its edge along the top of the foundation-- via a vent that looks similar to a clothes dryer vent.

I am just uncertain about how much CFM power I need in the fan, as well as the ability of a 3.25x10" duct to suck enough air.