In my house the nature of the construction causes the rigid vent pipe for the dryer vent to be about 22 to 23 feet long including the vertical rise in the wall behind the dryer. The 4 inch diameter vent runs horizontally for most of the distance between joists in the garage ceiling before exiting through the back wall in the garage attic space. Due to the routing there end up being a total of 8 turns in the vent pipe as can be seen at the indicated elbow locations in the layout diagram below.

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As you can imagine cleaning this vent pipe is a total pain that takes a good half of a day which involves taking joints apart and having to crawl into the tight space under the garage rafters. Regular cleaning is necessary because the the long run with many turns causes dryer lint to accumulate in the pipe.

Would it be an advantage to install some type of inline booster fan unit to increase the flow rate in the pipe?

It seems like this could blow out more of the airborn lint coming from the dryer and also help the vent line dry out after the cloths dryer is used.

  • I have no experience with booster fans in dryer vents. But: Have you considered roof venting? – longneck Jun 25 at 15:41
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    For a dryer vent to meet code, it must be less than 35ft minus 5ft for each 90 degree elbow. If you have 8 elbows, the maximum length of the run allowed by code is 15 ft. A booster fan would bring you back up to code, but it might be easier to find a straighter run. – Stephen Meschke Jun 25 at 19:40
  • Unfortunately there just is no real other option to change the run unless I just vented to my garage - but I am not going there. – Michael Karas Jun 25 at 21:03
  • I agree with Stephen and will go a step further to say that there could be a temperature difference going from conditioned space to ambient air causing condensation and making the lint sticky. – user1946891 Jun 25 at 21:09
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    Oh, and boosters I've installed have specified that they need to be cleaned regularly, so choose your location for cleaning convenience. – Aloysius Defenestrate Jun 26 at 3:44

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