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dryer vent runs 40’ with 9 turns

January 11, 2019
We are building new townhouse - semi custom. This week we were allowed a visit to view I side before walls are closed. I noticed that our dryer vent turns 9 times and is running 40’ long before it vents outside. My concern is lint accumulation and efficiency of our dryer. The installation manual says max 4 90 degree turns and 85’. Some of the turns are less than 90 degree but majority are 90 degree turns. I wrote to the builder and am waiting for the answer. In the meantime what do you guys think? So many turns, will the dryer work efficiently and is there a fire hazard of lint accumulating in these turns and twists?

Comments (51)

  • Michelle misses Sophie

    2015 International Residence Code

    Specifically M1502.4.5.1

    35 ft long max, reduced by equivalent length introduced by the turns, with manufacturer's instructions taking precedence if they state shorter

    So - no, it's not acceptable nor to code

  • NHBabs z4b-5a NH

    Definitely get that changed! Glad you were paying attention and caught this fire hazard.

  • Mrs Pete

    This is a fire hazard!

  • zouye
    Thank you! I am now waiting for builder to get back to us. Glad I paid attention but I have been concerned about where we placed washer and dryer from the beginning and it was always dismissed as a non issue... I thought they would vent it to the front not to the side wall... very worried what they will say. They are supposed to be closing up walls next week....
  • dadoes

    That's a horrible exhaust route. Dryer performance will be marginal with the excessive number of turns. Restriction on the airflow also causes an electric heating element or gas burner to run hotter than it should, which will 1) reduce the service life of an electric element and 2) probably cause the protective overheat thermal fuse to blow requiring a service call (repeatedly until the exhaust is routed in a better way).

  • Rob390

    We had the same issue with our builder. I told him several times I wanted the dryer to vent under and to the front of the house to provide as short of a run as possible and to make it easier to clean. Came in one day during construction and the vent went up and over two small rooms and out the roof! Needless to say that he was ripping it out and redoing it the way I originally requested the next day.

  • MizLizzie

    Good heavens. Where was the building inspector when all this was going on? Where I live, they’d draw and quarter the contractor for that.

  • dadoes

    I looked closer at the pictures. You have 10 turns. The first one also counts (arrow). I don't have even one turn. My dryer exhaust is a straight shot through an exterior wall. I can reach through the exhaust hood and touch the dryer's blower.

    And assuming that *is* the exhaust duct, why is it so high up on the wall? It should be down at the floor behind the dryer at its blower outlet.

  • zouye
    I know nothing about city inspector’s responsibilities in our city. I spent an entire day online looking for rules or code or smth and found zilch. I am going to go to townhall on Monday to ask who is in charge and what they check for and what are my next steps cause no news from builder. Today I drove by the site and they started putting insulation into walls, it looks like they are moving on with construction.... If builder ignores me what are my next steps? I need to get educated on that part ASAP.
  • Snaggy

    Q..why cant it go out through the wall on right or is that an inside wall ?

  • enduring

    If all else fails get a ventless heat exchanging dryer and skip using the vent. People like them.

  • PRO

    If you want dry clothes in a reasonable amount of time? Change the location of the appliances.I have a client with half the turns, half the distance, and it needs to be cleaned out all the time. Still won't dry well, even when clean.

  • PRO
  • Susie .
    Yes, you will be drying clothes all day with even an 85’ run, and cleaning lint will be impossible. I’d figure out a way to bring it down to half that amount.
  • Rob390

    @dados - It looks like a stackable W/D may be planned since the water and drain are way to close to the space where the dryer would go.

  • tiffany66

    What a great catch on your part.

    First take tons of photos. Document your request in writing (emails, text, letter, etc) to the Contractor to fix the Vent to the specifications of your dryer and Code. Also, send him written notes (emails, text, letter, etc.) acknowledging any of his verbal responses, i.e., "Per our recent conversation, what I understand you to say is you are unwilling to change the routing of the dryer vent even though I have informed you it does not meet Code." It's a way of establishing a paper trail of his verbal comments.

    This vent configuration exposes you to more than a slight risk for fire as well as making your dryer inefficient and shortens its life. Additionally, how will you be able to have this vent periodically cleaned out in the future with a long run and its twists and turns. Plus if your contractor is this lax in routing this vent, who knows how well he taped the seams and if he even used the proper tape on them. Why does #1 Elbow have such a wad of tape around that elbow -- seems overly large.

    I'm assuming the vent opening in the wall is high for a stacking W/D. In the photos I can't see where your gas line is for a gas dryer.

    Realistically your dryer can only blow the lint just so far. NOTE: within that vent is not only lint, but MOIST lint from the Condensation from the dryer. Basically the lint that can't be blown out of the vent pipe to the outside will continue to accumulate within it. In your case, the accumulation most likely will be at the first elbows out of the wall. If that accumulation happens near the wall hookup to your dryer, you can have some major problems with the efficiency of the dryer.

    I just finished getting myself educated on dryer vents because I am reversing the utilities and dryer vent to opposite sides of the same wall. This is being done so that my new appliance doors will open like French doors rather than back to back. In my city 35 feet is max. for the total run, but that amount is reduced 5 feet for every 90 degree elbow. I just checked my Dryer Manual and its only 28 ft. with 4 90s. In your case 10 elbows means Zero amount of duct work can be attached to your dryer. How does that work???

    If you had a City Inspector, then you could just call his supervisor, ask what Code is, tell him your concerns and ask him to reinspect but with new inspector.

    Here are some other sources you can contact. The Gas Co. if its a gas dryer. They have strict policies regarding this potential fire risk. Here the Gas Co. comes out for free to inspect. Next, check the specifications set forth by your dryer mfg. It clearly outlines the requirements for the vent. This probably over-rides all other specs.

    If your Contractor is unwilling to fix the problem and the City won't enforce, as a last resort you can contact your State's Contractor's License Board. They will take this seriously.

    I would tell them if the vent is left as is you will contact your lawyer to put them on notice that you will be holding them responsible for any future financial costs to you should this result in a fire, damages, or injury to anyone as a result of construction. This usually wakes people up.


    I'll give you a personal experience I had when I went to visit my Parent in their new condo. Vent pipe ran straight up through the roof with only one elbow at the point of entry in the laundry wall which was a shared wall with their neighbor.

    Mom complained that her thin nylon nightgowns, blouses, etc. were taking as much as 40 minutes to dry. Heck even a hair blower could have done them faster, so I figured something was way wrong. Everyone else dismissed her -- Oh she's just not used to the new dryer, YaDa YaDa.

    My first thought was check the new dryer (only less than a year old). But then when I pulled it away from the wall I could smell gas really strong and immediately called the Gas Co. Within a couple of minutes of going in the laundry room he had us evacuate the condo because of a major gas leak. Apparently the Appliance Dealer who hooked them up used the wrong metal (brass) fittings and the gas was corroding them week after week -- hence the leak.

    When we returned, he said we were extremely lucky to have not had a fire with that much of a gas leak. He then showed me the 7-8 inch wad of lint he pulled out of the first elbow in the wall to the dryer before it went up vertically. This would also have caught fire and possibly burned both condos.

    He said the vertical vent pipes are the worst of the bunch. What happens is when the gas dryer is blowing the lint goes up the pipe UNTIL the dryer stops, then all the lint within the length of the pipe will fall to the bottom. Because the lint is damp with Condensation, as it dries it clumps together and keeps accumulating. This then blocks the vent and the diameter inside the pipe shrinks because of the lint ball. In Mom's case, with the gas leak and the dryer running it could have caught fire and the lint ball with it.

    The only way this vertical vent application is good is to be dedicated to YEARLY cleanings to minimize lint blockage.

    Hard to imagine this huge lint ball developed in less than 12 months. Their laundry loads were small and the fabrics were not heavy lint producers -- lots of silky or light weight fabrics -- no heavy towels or robes.

    Before I came to town Mom told my sibling and the appliance store, but both dismissed her complaints and told her to just run the dryer longer until the clothes are dry. I cringe at what might have happened, if I wasn't so persistent to get to the bottom of the problem.

  • tiffany66

    Here are two new elbows that I came across for my laundry room. Using these elbows has the same flow as a straight pipe and without any deduction of feet on Code length for this elbow. They have two sizes a Long Ell or a Short Ell see their website @ Dryer-Ell

    Buy using this DryerBox you can recess your Dryer hose into the wall cavity. This will allow you to position the dryer closer to the wall without danger of collapsing the hose.

    This box could eliminate your first elbow at the wall. They have various sizes and configurations. Plus their website has a lot of good information. See the mfg. website

    DryerBox recesses dryer hose into wall.

  • zouye
    Thank you everyone! Still no response from the builder.... I am in full freak out mode. Monday it’s city hall and registered letter to the builder. Then consultation with dryer vent specialists in my city to get 2nd opinion. I have no problem moving laundry room. I was never told that it was a bad location. The wall on the right is a common law with neighbour. It’s an electric dryer. It’s supposed to be stacked. I had to pay extra $2000 to have my laundry room on the 2nd floor and for extra plumbing etc. Builders’ Engineers and project managers signed off on the plan. They are very reputable and have build hundreds of houses in our neighbourhood. I don’t know what’s going with all these twists and turns. I even have a video of how the duct runs and they could have done all of this in 2 turns or less but they went all around the wood structure, some times wrapping themselves around a 2x4 like a snake. It makes no sense.
  • tiffany66

    Tell him you may file for a "Cease and Desist Order" That could wake him up.

    As reputable as they are, sometimes they just don't supervise their people. Contractor should have known better. This ductwork is indefensible. Imagine the grief you would have had later, had you not known better.

  • tiffany66

    Good Luck to you Zouye, hope all works in your favor. If its not to code he will have to correct it. Let us know how it goes on Monday.

  • dadoes

    "Rob390: It looks like a stackable W/D may be planned since the water and drain are way to close to the space where the dryer would go."

    Ahh, yes. A stacked set. I hate those. Causes trouble with service access. I did a repair on a stacked frontloader set at one of my neighbors rental properties last week. Dryer issue. It's an older WP set with toekick panels so I was able to access the specific dryer parts by removing its toekick panel while still atop the washer (although the dryer had to be leaned back a bit). It needed to be fully disassembled to clear some years of lint accumulation inside the dryer but that would have required taking the dryer down, which involves pulling a mess of junk the renters have on top of it and also moving a refrigerator, so I only cleared what I could access on the right side with the toekick off.

  • Snaggy

    * The wall on the right is a common law with neighbour.*..sorry don't know what that means ..are you a semi detached house ?can you move the washer etc to the back of the house so you have an outside wall ?

  • PRO
    Patricia Colwell Consulting

    Move the W/D to another spot or vent straight up through the roof . I can’t figure out what the issue is to warrant this ridiculous route for any kind of venting.

  • zouye
    @snaggy yes, it’s a townhouse and we share wall with neighbour. Our master bedroom is in the back so it would have to move to the basement, however, plumbing is all done so not sure if it’s possible. Called sales rep at the builders company yesterday and he told us to wait for the answer. We should get it and not to worry since we have new house warranty. Still going to follow my plan for Monday.
  • Michelle misses Sophie

    FYI, new house "warranties" generally cover for a limited period of time on construction defects as they relate to the house being habitable. Don't let them tell you the warranty will cover this.

  • zouye
    Update: went to city hall today. Talked to a very nice person who explained that city does not regulate length of ducts. During city inspection they only check where the exit is and that it meets the norms on exterior. Apparently it’s up to the builder to build things per code and if we don’t agree it’s a civil matter. Not very comforting but it is what it is. She did say that the builder must respect dryer norms so at least there is that. I am still waiting for response from builder. I am giving them 10 days as recommended by builders association and then we will send registered letter. Very nervous about how it will all be resolved but strongly feel that we are in the right and dryer won’t work efficiently and is a fire hazard. Going to call some dryer vent experts this pm to get 2nd opinion.
  • georgect

    Stand your ground Zouye.

    That dryer ducting is ridiculous.

    It's supposed to be the straightest, shortest route as possible.

  • zouye
    Update: builder got back and they will add a booster fan to remedy the situation. I am consulting with experts for 2nd opinion. Anyone has experience on booster fans?
  • georgect


    Still there are too many turns to effectively clean it out.

    I would NOT do a booster fan.


    At this point (as this problem may hold up ongoing construction process), I would gather 2nd opinions from dryer venting pros, compare that info to the floor plan and see if there is another way to get as straight and short a shot to an outside wall for venting given that your current venting set up is convoluted at best. If the rerouting for a shorter and straighter shot outside is truly not feasible, a condenser dryer is likely your best compromise. While I personally would prefer vented, *if* my situation was like yours, I would choose to go ventless and deal with it.

    For note, my vented dryer is located on an outside wall with a straight and short shot to the outside and I have gobs of lint outside my vent. I mean GOBS of it. I have to scrape and dig it up when I can't take looking at it anymore in my graveled natural drain beds. I can easily fill a kitchen sized waste can with 3 months worth of lint accumulated. When I am out there hacking and scraping away at the lint formations, I tell myself while this is no fun (!!), it's better to have the lint out here in the gravel beds than inside the exhaust tubing waiting to catch fire. My purpose for sharing this with you is that lint accumulation is a real issue dryer users must deal with. With those twists and turns and unrealistic length of venting tubes your contractor has put in, I can't see how you will be able to keep it safe. Even with the best of dryer vent cleaning tools and accessories.

  • Snaggy

    My mum has a non venting dryer ..works well ..just clean the lint trap every 2 weeks ..its a thought..would be safer than all the bends in that duct work!

  • zouye
    @Snaggy thank you. I have started looking at some models but I prefer vented. I am hoping that builder can resolve it. So far my phone conversations with other experts went like this “how many elbows? You’re kidding right? “ and the worst is that we have 2 elbow to elbow connections which means air is choked in this 2 spots. I don’t think the booster will do it. I also emailed booster manufacturers last night with photos asking them if booster fixed those problems. Waiting for an answer. Also informed the builder that their one line email is not enough and we need to have a conversation, discussion with options, literature on the boosters, etc. I personally don’t want the booster because it’s another thing to maintain in the house but I am keeping an open mind.

    Anyways, what a disaster. Can’t believe that reputable builders do this and something as important as venting is spotted by a “civilian”. Note to self: Read up and get informed and be vigilant when building a house. It’s your biggest investment, it’s just another house for the builder.
  • mamapinky0

    Whose working for who here? The contractor is working for you. Put your boots on and start stomping.

  • greenfish1234


  • zouye
    Update: they are rerouting the vents. Promised only 3 turns. Visit tomorrow to document new location. So excited!!!
  • PRO
    Diana Bier Interiors, LLC

    Good for you, zouye!

  • hcbm

    Just a thought, if they are doing this in your unit what about the attached units? If it is the same in other units, the other units could also have a fire and you are all attached and might even share a common space between the ceiling and roof? That would be very worrying to me.

  • zouye
    We are the only unit that chose that location for washer/dryer. Everybody else kept it in the basement. I had to pay $2000 for that location extra plumbing, etc.
  • hcbm

    That's great that you don't have to worry about the other units. For $2000 they should give you what works well. Glad you have a resolution.

  • zouye
    Hi Houzz community. I want to say a great thank you for all your comments and support. It’s so nice to talk to somebody and do the sanity check. Thank you again for all of your inputs!!!
  • zouye
    Omg friends. The saga is not over. Just got pictures from builder because they had to hurry up and close walls and this is what I see. What do you think is this material? It looks like aluminum foil to me. Then per dryer manual it’s not allowed. Or is it semi rigid? If so I think it’s longer than 8’ that are prescribed by our manuals. Given the ceiling support framing it looks longer than 8’. Thoughts? I emailed the builder and am waiting for an answer. I stopped by today and they closed the ceilings already. I have no problem taking down that ceiling on day 1 of possession to double check what’s up there but I rather fix it now. Will this dryer nightmare ever end?
  • greenfish1234

    I know nothing about nothing but that looks like hvac material, not a dryer vent.

  • Michelle misses Sophie

    Agree with @greenfish1234 - that looks like HVAC ducting, not dryer vent. Hard to say if it is rigid or flex. It *might* be rigid with an exterior insulation layer, but you cannot tell from a photo.

  • wacokid

    It is a foil insulation duct wrap, perfectly appropriate for that application. I would not stress out over this. Your dryer will exhaust air into the duct and it will eventually makes its way out. It is not a fire hazard as stated above. The heat from a dryer dissipates quickly and your builder really did a nice job with the duct material he used and adding the foil insulation is a bonus. I'm sure if he could have routed the exhaust to the exterior anyway else he would have. As far as lint, your filter will catch most all of it. You might check after 6 months or so if any lint is building up just behind the dryer. Your overall construction is top notch.

  • jwvideo

    They may be trying to pass that off as "semi-rigid" ducting or maybe it might be a wrap on rigid ducting. If it is not a wrap, that would just be wrong. Check out the code link in Michelle's post above (I think it was the second response.) Specifically, M1502.4.1 requires smooth rigid ducting except for short transitions from the machine to the ducting in the wall.

    Do you have a purchase contract or a contract with the builder? It should say something about construction meeting code requirements or being in compliance with laws and regulations. Find out if the ducting was wrapped or if they took a shortcut and used semi rigid ducting (which would not be good and workmanlike construction to me.) And, they want to charge $2k for this if it is semi-rigid? It is unusable. If it were me, I'd be inclined to demand they drop the $2k charge (if I had not already had to pay it) or at least give you an equivalent credit so you can buy a ventless dryer.


    Go ventless. Save your sanity.

  • dadoes

    That may be an insulation wrap on a solid flue duct. It *should* be insulated, particularly when passing through an unheated space. Hot/moist air will be passing through and condensation inside the flue should be avoided as that will cause lint to stick. Perhaps squeeze it gently to check if there's solid ducting inside.

  • Michelle misses Sophie

    One additional option to consider with a long-ish duct run, do you have room for a secondary lint trap to be installed in an accessible location?

  • Rob390

    My builder did put an inline lint trap in when he routed the duct up and out the roof before I had him redo things. Something like this, now that the wall is sealed, may work: Lint trap

  • dadoes

    My concern about an extra filter such as that is that the lint particles that pass through the dryer's onboard filter are smaller bits of material and a filter to catch them must be more restrictive. It may clog quickly and reduce the airflow rate. Also, it's harder to blow air through a screen or filter than pull through it. Dryer (and HVAC and range hood) filters are always positioned in the airflow stream such that air is pulled through, not blown through. Place a fan in a screened window positioned to blow through it from inside to outside and check how much airflow there is outside vs. how much hits the screen and backflows around it.

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