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Community and Q&A

Wall vent vs. roof vent

Matt Cibula | Posted in Mechanicals on

We are installing a custom wood range hood and can’t decide between venting through our wall or heading through the roof. The duct is 6″ round. Going through the roof the run would be about 3-4′ straight up. Roof is pitched about 5-12 and the vent cap would land right around 30″ from the eave.

The range sits on an exterior wall, so heading though the wall would give the run a 90 degree turn and about 2′ of ducting. The siding is 4″ lap fiber cement. Any pros or cons or suggestions to persuade me one way or another?

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  1. David Meiland | | #1

    I'd go through the wall.

  2. Charlie Sullivan | | #2

    Roof penetrations are hard to seal well. So all else being equal, the wall is the way to go.

    If it's custom, why does the wall direction require a 90 degree bend?

  3. Matt Cibula | | #3

    By custom I mean we are making the hood surround. The power pack/insert has the 6" port and damper on the top of the unit.

  4. Matt Cibula | | #4

    Could I use a 6" round up the wall and then convert it to a 3.5 x 10" duct as it travels through the wall? Or would flow be reduced? This way I wouldn't need an expensive hole saw to cut my interior/exterior holes??

  5. Expert Member
    Malcolm Taylor | | #5

    Matt, Yes you could, and there are good exterior flappers for that size. However i wouldn't make the decision based on buying a hole saw. I cut any vent opening over 4" with a jig saw.

  6. Matt Cibula | | #6

    Thanks. Want just about the hole saw. I also couldn't make the exterior look right since it's already sided. I wanted to install a pvc block and mount the vent cap to it, but the 6" round vents are so large 9x9 compared to the 3.25x10

  7. Expert Member
    Malcolm Taylor | | #7

    No problem with what you propose. I prefer the look of the rectangular ones too.

  8. David Meiland | | #8

    IMO the best wall cap is the 6" round Seiho. If you're hoping to get much air sealing from the wall cap, go that route. The 3-1/4 x 10 models are not as good. I think at this point I've tried 'em all, including buying some to check out that I decided weren't even worth using.

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