GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Dryer vent recommendations?

Lucas Durand - 7A | Posted in Green Products and Materials on

Martin,
Wasn’t there a particular dryer vent outlet you were a fan of?

Was it the “Heartland”?

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.

Replies

  1. GBA Editor
    Martin Holladay | | #1

    Lucas,
    The Heartland is a good one. That's the one I have on my house. It's a pain to disassemble and clean, however.

    Another really nice one is the Seiho dryer vent termination. It's made out of stainless steel.

  2. Lucas Durand - 7A | | #2

    Martin,
    Thank you.

  3. David Meiland | | #3

    I recently used a Seiho SB on a job, nice if you have to look at it or walk past it http://www.seiho.com/product/sfb/sfb.html

  4. Garth Sproule 7B | | #4

    Lucas
    I have installed several of the Heartlands over the years and they do work very well if they are cleaned regularly (at least once a year). Have you thought about makeup air for the dryer? I have never tried this, but what about installing an additional Heartland on the interior, somewhere near the dryer?? It should open automatically when the dryer creates enough negative pressure...

    Or, if you are running an HRV, you can just let it run unbalanced while the dryer runs...

  5. Lucas Durand - 7A | | #5

    I have never tried this, but what about installing an additional Heartland on the interior, somewhere near the dryer??

    Garth that's an interesting idea...
    My plan to this point has been to frame a sort of "airtight" closet around the washer/dryer and weatherstrip the closet door(s)...
    What I haven't decided on yet is how to best provide make-up air to the closet and (since the washer and dryer don't stack) what kind of door I could use that could be weather-stripped and would be wide enough access both machines comfortably.

    I'm starting to think it will be less work to just convince my wife we should sell our dryer.

  6. Garth Sproule 7B | | #6

    Lucas
    I can remember bringing in frozen laundry from the outdoor clothes line when I was a wee lad...I'm with your wife on this one.

    If the passive make-up air vent is somewhere near the dryer, I don't see the need for the "airtight closet". In a very airtight home, it will only admit outside air when the dryer runs, and will probably speed up the drying process, as the incoming air will have a very low absolute humidity level (in the winter).

  7. Lucas Durand - 7A | | #7

    Garth,
    You're right that I'll need to come up with a more creative argument than hanging our clothes on the line in winter.
    Maybe an indoor drying closet...

    As to the "airtight" closet for the dryer...

    I worry about smoke spillage when loading the woodstove while the dryer is running.

    R. Riversong has advocated weatherstripping the laundry room door, but surely that must mean that the laundry room is somewhat "tight" or there wouldn't be much point...

    I wonder if locating a source of make-up air next to the dryer is sufficient?

    Maybe a not-so-tight closet with make-up air inside will be good enough?

  8. Garth Sproule 7B | | #8

    Lucas
    My thinking is that the air that is exhausted by the dryer will cause a negative pressure, and that the "replacement" air will tend to follow the path of least resistence. By providing a 4" Heartland type vent hood for make-up air on the "inside" of the laundry room, you should not experience any problems with the wood stove etc. The stack effect should keep the draft in the stove pipe going and would reqiure some significant negative pressure to reverse it.

    RR's advice about weatherstripping would indeed make some sense if there were no source of make-up air nearby (but the dryer has to get air from somewhere). BTW, are you planning an exhaust only ventilation system, or HRV??

  9. Lucas Durand - 7A | | #9

    Garth,
    I'm planning on an HRV. I was a closet exhaust only fan for ages but I think in my case it's the better way to go.

    The idea of the "airtight" closet was to help ensure that the "path of least resistance" would in fact be the source of make-up air (also located in the closet).

    Thinking about pressure dynamics sometimes makes my head hurt. There are so many variables.

  10. Garth Sproule 7B | | #10

    Lucas
    I am certainly no expert on pressure dynamics, but for what it is worth, here is what I would do. Forget about a make-up air vent for the dryer. Just make sure there is a fresh air vent from the HRV somewhere nearby, and the HRV will supply the needed air (it will simply run unbalanced while the dryer is on). This has the small advantage of some heat recovery...

    Your wood stove should have its own dedicated combustion air supply, and therefore should not be affected much by the intermitent negative pressure events.

    Maybe there are some actual experts out there with some good advice????

  11. GBA Editor
    Martin Holladay | | #11

    Garth,
    I have never heard of a home that was so tight that the dryer was starved for air. Almost all homes should have enough cracks that you don't have to worry.

    Passivhaus builders often install condensing clothes dryers, but the reason isn't that a conventional dryer would be starved for air. The reason is that they don't like the fact that the exhaust vent leaks air in both directions when the dryer isn't running.

    Here are a few simple tests:
    When your dryer is running, can you feel the exhaust leaving the termination at the outside of your house? That means it's probably working. If the exhaust is weak, check whether the duct has been recently cleaned of lint.

    Second test: do your clothes dry in a reasonable amount of time? (Again, check the filter and duct for lint before assuming another problem exists.) If so, your dryer is getting enough makeup air.

  12. Lucas Durand - 7A | | #12

    Just to clarify:
    I'm not too worried about the stove when a fire is burning with the door closed, just when opening the door to load while the dryer is running.

    The stovepipe will go straight up about 25' from the stove to the cap and most of this length is in conditioned space so the draft should be quite strong...

    But if a strong stack effect is present and then I start exhausting 250 CFM (I think this is about an average rate for a dryer) out of the basement - and no make-up air is available - will the chimney draft still be strong enough to prevent spilling smoke into the house when the stove door is opened?

    Or am I over-thinking this?

    Ideally, I would like to limit the number of envelope penetrations to the bare minimum possible so if make-up air isn't required so much the better.

  13. GBA Editor
    Martin Holladay | | #13

    Lucas,
    it sounds like you are more worried about the amount of combustion air available for your wood stove than you are worried about makeup air for you clothes dryer. If my guess is correct, the usual solution is to provide ducted combustion air to your wood stove.

  14. Lucas Durand - 7A | | #14

    Martin,
    Sort of...
    The stove has its own ducted air supply that comes in from under the slab, so the stove should run fine with the door closed.

    I'm just wondering if , while running the dryer with no make-up air, opening the door to load wood is going to get me a face full of smoke and ash.

  15. GBA Editor
    Martin Holladay | | #15

    Lucas,
    I think you are overthinking the issue.

  16. Lucas Durand - 7A | | #16

    Martin,
    I was starting to think so too.
    Thanks for the reality check.

  17. Garth Sproule 7B | | #17

    Overthinking is a good thing...I am betting that with Lucas's attention to detail, that his home is likely to be "very" airtight!

  18. David Meiland | | #18

    Lucas, I think you're the guy that's going to invent the two-pipe heat-exchanging dryer intake/exhaust system. Motorized damper at the wall cap? I'll buy one from you.

  19. William Geary | | #19

    Lucas,

    I'm with you on this one. For my hot water heater I went with a direct vent unit that gets combustion air from the outside and blows the exhaust outside.

    I looked into a weathersealed upstairs laundry room for both "green building" and noise isolation reasons. After investigating makeup air for the dryer in the end did not do it, primarily because it meant going through the roof on or near a roof valley and I wasn't going there. I did use an electric dryer instead of a gas dryer so I wouldn't have to worry about combustion gases.

    A couple of points:

    Code may well require vents on the room with the dryer. Code usually means makeup air or vents both low in the room and high in the room. Read your dryer installation manual and it should tell you how many square inches of vent space you need.

    I was going to use a motorized damper as well. The better ones have rubber seals.

    One of the issues with makeup air for a dryer is the same as makeup air for a powerful kitchen vent hood -- you get cold air in the winter (not great for drying clothes or for those hanging out in the laundry room or for the water connections to the washer if you're bringing in freezing air) and you get hot humid air in the summer. This raises all sorts of house design, insulation, water vapor, and possible mold issues.

    I also wondered why they don't make "sealed combustion" type dryers that bring fresh air from the outside and blow the exhaust out. The main problem is that most of the air isn't for combustion, and in an electric dryer none of it is for combustion. Instead, the air is for drying the clothes! I'm not sure you want to do that with freezing winter air (think freeze-dried clothes -- just add water before you wear them :-) ) or humid summer air. The exhaust heat exchanger may be OK in the winter but not in the summer. But maybe it could work.

  20. Lucas Durand - 7A | | #20

    David,
    You're on ;-)

    William,
    Thanks for your perspective. That's a good one about code requirements, if any...

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |