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Community and Q&A

Dryer vent in air-tight Passive House

user-175166 | Posted in PassivHaus on

I am building a house in the Seattle area to Passive House standards. After spending countless hours sealing every crack, seam and penetration to achieve under 0.6 ACH, creating a 4 inch diameter hole in my air barrier pains me. I’ve looked into condensing dryers that are used in some European Passive Houses, but they seam to take much longer to dry and use lots of water. Since I will be installing a vented dryer (unless someone can come up with another solution), are there ways to make the dryer wall vent more air-tight when the dryer is not in use? The wall vents I’ve seen in big box stores don’t seal at all when the flaps are closed.


Gerald Blycker

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  1. STEPHEN SHEEHY | | #1

    Whirlpool just started selling a heat pump dryer. Pricey: about $1500, but no vent and cheap to operate. I'm planning to get one for my new house. I'm trying to minimize holes in the walls.
    Are you sure condensing dryers use water, as opposed to produce condensate that gets drained into the washer discharge pipe?

  2. GBA Editor
    Martin Holladay | | #2

    Many builders install this exterior termination for a dryer vent:
    Heartland dryer vent termination

    It's also available from:

    If you do a GBA search on "dryer vent," you'll find lots of information and similar threads on this topic.

  3. josh_in_mn | | #3

    I have one of these on my house, and while it works okay, there are some drawbacks.

    1.) The plastic yellows and becomes fragile in a relatively short period of time. Mine is ~8 years old and is pretty much shot. A chunk of the lid has broken off.
    2.) You need to clean it frequently, otherwise it gets gunked up with lint and restricts flow or doesn't close well.
    3.) It's pretty ugly.

    I have one of these going in when we re-locate our laundry upstairs. No usage yet, but the unit is solidly constructed from aluminum, and looks great. Sealing of the back draft flap is good, but not excellent, there are a few small gaps near the hinge pins.

  4. CramerSilkworth | | #4


    You want one of these:

    Not the prettiest, but they work great. They have magnets on the flap that hold it shut until the dryer comes on. And as it happens, they stay shut until about 60-70 Pa, just over the Passive House blower door test standard of 50 Pa. The few I've tested, anyway. You may need to play with it a bit, and maybe add some thin weather stripping. Other ones, like Martin linked to, start to open at lower pressures. The magnets are key because they hold tight until the threshold pressure, then once it pops there's no additional resistance.

    More info in a presentation I gave with a colleague at the NAPHN Conference in Maine two months ago here:

  5. dwarkentien | | #5

    Go with the Whirlpool Heat Pump dryer, just announced in late 2014.

  6. jackofalltrades777 | | #6

    I concur with David. Get the VENTLESS Whirlpool Heat Pump Dryer. Problem solved!!

  7. LenMinNJ | | #7

    We went though the same decision process with our Passivehaus design in New Jersey. We started out really wanting a vented dryer, but getting the insulation and sealing of the vent lines and outlets right really took way too much effort. We decided that the only way to make that work was to put the laundry room outside the thermal envelope of the house. And that was too much effort and cost!

    So we went with an LG condensing dryer, and though we expected it might be a problem with longer drying cycles and incomplete drying, it hasn't been. It works great and we don't feel that we're missing anything by having it.

  8. dburgoyne | | #8

    Has anyone used this magnetic catch vent product? Just wondering how well it may seal.

  9. jchas | | #9

    We've been using a Broan-Nutone EV100 eco-vent for 3 years now. Uses a styrofoam ball as the flapper, so insulates and seals well when it's shut.

    I'd recommend it:
    click here for eco-vent website

    Home Cheapo sells them here in Canada.

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