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We recently moved into a house and hooked up a new (LG) washer and dryer. The dryer was showing us an error message related to decreased performance due to poor venting exhaust. I went outside to see where the exhaust was and encountered this:

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The dryer is venting up out of the ground:

enter image description here

After some searching, it looks like this is one of these dryer vent seals. The original owner says there used to be a cap on top, but it came off some years ago. From the few YouTube videos I was able to find though, it looks like these should be used above ground and the vent air down through the bottom of the top piece of the dryer seal vent, which can't happen here because the bottom of the vent is pressed against the ground/mulch.

I talked to the home inspector (this was not mentioned on the inspection report) and he says that this is fairly common with slab houses in my area.

So three questions:

  1. Is this actually ok or common? I've never seen anything like this, but this is my first home purchase.
  2. How bad is this? It seems very bad to me. The most frustrating part is that the dryer is right next to the outside wall, so a straight pipe out to the porch would work fine. I plan on getting that done at some point.
  3. What is the right way to maintain this until I can get (2) accomplished? I considered buying a new dryer vent seal like I showed and replacing the top part, but something feels off here.
  4. Why would you ever do this instead of venting directly out of the exterior wall? The only idea the inspector had was aesthetics.

I should note that our dryer vent coil on the inside is much too long, which could be contributing to the poor venting situation. It might be the case that once that is fixed, there's enough airflow to force the cap up and vent somewhat properly.

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  • I guess, besides the cap, there was a flipper at the top end of the pipe to prevent dust from getting in. Maybe just replace the pipe and extend above the ground and potential water pool. – r13 May 20 at 0:35
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    The first thing I would do is run the dryer and and make sure there is a hot air escaping from the existing vent. Then you can decide on replacement strategy. If there is no air coming from the vent, then there may be blockage which would require cleaning/examination the exhaust pipe first. – Jon Raynor May 20 at 14:02
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I have seen this type dryer vent many times in South Carolina. The termination has to be kept clean of debris. There should be a cap that includes a way of keeping water out.

Over time yard workers etc will stack up pine straw or mulch around these and that can lead to problems especially if the cap gets damaged or lost.

When I have had to repair I add some length to get the termination up out of possible water intrusion and put a 180 degree fitting on it to insure rain or roof run off doesn’t fill the tube. A varmint guard is good too.

Also I run a long hose from a wet vac in the tube to clear any sitting water.

This will help but the hot air from the dryer feeding into a cool underground plastic pipe is not a good option. Condensation is going to occur. Eventually water will begin to build up in the pipe restricting air flow.

If you are stuck with this set up plan on regular cleaning and drying of the tube.

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  • Thanks for this information. I am in South Carolina, so good to know this setup is somewhat common – Andrew Whitaker May 20 at 19:57
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  1. If the vent is obstructed or becomes obstructed due to lack of protection, that is a problem that could cause a fire, so it is not OK. In my area it is not common, but if you look hard enough you can probably find many areas where a certain questionable install is typical. Doesn't matter at all if it's common or normal if it creates a problem.

  2. If the vent clogs and you don't have a super fancy modern dryer with air flow detection, it could cause a fire, potentially costing everything you own or your life. On the other hand it looks super easy and cheap to fix and the building hasn't burned down yet, so how do you evaluate bad?

  3. For a temporary protection measure, thoroughly clean out the vent and then protect it so nothing can get in it. You can't reduce to holes of lower cross sectional area than the pipe, so you could take a large bucket, turn it upside down and cut suitable sized holes low on the bucket. Put some steel mesh over the vent to keep rodents out, place the bucket over top and put a brick or rock on it to hold it. If you do buy a replacement cap, you need to dig around the base of the head and ensure both that it remains unobstructed and that rodents can't climb into it. Note that a layer of mesh must be larger than the pipe it obstructs proportional to the % area blocked by the mesh. At a later date either vent it out at a suitable height or add more enduring protection for the head, like a tower to put it out of reach and a suitable replacement head.

  4. You'd have to ask the guy who liked the method enough to repeat it. Aesthetics, cost or the addition of a "feature" are potential reasons. Nobody thinks of everything and product decisions are not always made by those with practical knowledge and experience. A few seasons of landscaping and spring cleanup added dozens of things I would think about when designing a fence or a yard. Judging from the way 80% of yards are designed, most of the people designing them for large complexes have no experience whatsoever maintaining them commercially. Note that this could have been originally OK but complicated by landscaping/mulch being added at a later date.

A longer pipe restricts airflow more than a shorter one. If the flexible section indoors to connect to the dryer is too long, it may also necessitate unnecessary bends which will further restrict air flow.

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  • At least in my state (MA), I believe flexible ducts are not allowed for dryer vents. – Carl Witthoft May 20 at 14:43
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    @CarlWitthoft Even "just" between the dryer and wall? Can dryers not be moved once the duct is attached? I'm in New Mexico, and I've never had a dryer positioned in a way that I could access the back without pulling the dryer out of a cubby. The flexible vent is the only way I could connect and be able to slide it back into place. – Michael Richardson May 20 at 15:27
  • @MichaelRichardson I am not certain about that. You may be correct – Carl Witthoft May 21 at 11:58
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Are you certain your dryer vent is connected to this vent?

It looks like a “gravity radon vent” to me. I’d follow the inside vent to the exterior to make sure they’re connected.

I’d also dig down next to the outside vent to make sure the interior vent is connected to this vent.

A quick Google search shows that radon is common in South Carolina and often has levels as high as 70. Gravity systems are designed to be extended through the roof with an exhaust fan attached to assist the gravity vent if needed.

You may want to do a home test and see if the gravity vent is sufficient.

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    Yes, I'm certain this is the dryer vent. Hot, humid air comes out when the dryer is on, there is visible lint in the visible parts of the pipe. – Andrew Whitaker May 20 at 15:29
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    @AndrewWhitaker It could be both. It would be handy to tap into the radon vent for the dryer vent. – Lee Sam May 20 at 15:50
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    @LeeSam Seems possible, but then wouldn't some of the radon end up in the house?? – Joe May 20 at 17:50
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    @Joe - Sometimes people do idiotic things. – Hot Licks May 20 at 19:42

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