7

I live in Houston, TX (Very Hot, Very Humid). In the summertime, my dryer is dripping with water, when not in use. I do not have overly excessive drying times.

My dryer is vented via an unfortunate run of over 25 feet with two elbows. It exhausts through the roof. Dryer is in the center of the first floor, so the vent goes up to the second floor, runs through the ceiling/floor, comes out in an attic and through the roof. The attic is unfinished, with temps well over 120F on an average summer day in Houston.

My guess is that I have hot moist air pouring down my dryer duct, hitting my nice cool air conditioned dryer and condensating.

Initial google searches have pointed me at the Fantech DBF110 which is a booster fan that you install on your duct run. I'm not certain this is going to solve my problem, as it doesn't run constantly, only when the dryer is running.

Would I get more bang for my buck by insulating the duct and trying to seal it up? Any recommendations on materials if that's the case (thermal blanket, just wrap fiberglass, other)?

Update:

As Eric suspected, I didn't have a working flap on my dryer vent. So I bought one and gave it a test run and I wasn't happy with how little the flap opened from the pressure on the dryer. So, I installed the booster fan as suggested by Doresoom as well. We had a few hot humid days after that, dryer stayed dry. My clothes drying times are pretty low too, 30-45 mins.

vent

fan

Fan pic is before I cleaned up the electrical, looks a little neater now. The ideal install for that fan is with the bracket on a stud, unfortunately there was no good way to attach a stud and avoid cutting a new hole in the roof. Luckily the fan is pretty light.

Improve this question
2
  • I'm confused. You're dryer is on the first floor and the vent goes up and then through a crawl space? Do you mean an attic space?
    – aphoria
    Commented Aug 11, 2010 at 19:03
  • Yes, sorry. I have an attic over my second story that I call the attic and a little overhang (from the roof pitch) that's on the second story that I have to crawl into. Nothing under the house :)
    – Steve Jackson
    Commented Aug 11, 2010 at 20:10

5 Answers 5

Reset to default
14

Usually a dryer vent will have a spring loaded flap where it exits the house to prevent outside air (and bugs, rodents, etc) from coming in through the pipe. If you are getting airflow from outside through your vent pipe, it sounds like either you don't have one or it isn't closing. I would check that first.

Improve this answer
3
  • +1 It's very likely that this isn't closing correctly. Sometimes wasps like to build nests in this sheltered spot.
    – Rob Napier
    Commented Aug 12, 2010 at 16:49
  • Got on the roof last night. No flap at all, just a birdhouse looking thing to keep the rain out. I'm ordering one of these and hopefully my roofing skills are up to snuff. bathroomfanexperts.com/product.php?product=174479
    – Steve Jackson
    Commented Aug 12, 2010 at 18:13
  • My problem is the same but the situation is just the opposite, I have a very short (less than 12" 30cm run and there flap (plastic) is closing. Any ideas? Or should I make this a question of its own?
    – Duston
    Commented Aug 21, 2021 at 13:30
6

Depending on the type of duct you have, 25 feet and two elbows may be near or over the length limit for dryer vents without a booster fan. This website lists the limits.

Improve this answer
1
  • Thanks, I'll probably do that next, I'm sure the family won't complain if clothes dry faster.
    – Steve Jackson
    Commented Aug 12, 2010 at 18:14
1

I have seen this when the inside was kept cold by the AC, the moist air from outside would condense in the vent and come into the dryer. The dryer vent trap door would not seal completely. It is possible you have rain coming in,past the dryer vent trap door (if there is one). I would suggest having the builder move the vent low and out the wall instead of the roof. Try removing the vent from the dryer and placing the vent pipe in a bucket and see if you get water especially if it is raining. If you can look up the pipe and see if you can see daylight, if it is a big open circle (assuming round duct) the vent trap door is missing or stuck open.

Improve this answer
0

I suggest you take apart the dryer far enough to see if its internal ductwork is clean. One dryer I looked at that "wasn't getting things dry" was almost completely clogged inside. Another dryer with a similar, but not as severe, issue was 50% clogged.

Improve this answer
2
  • I dont think this answer is specific enough.
    – Rohit Gupta
    Commented Mar 21 at 12:27
  • @RohitGupta dryers have an internal fan and associated ductwork to get the hot moist air from the rotating drum to the vent on the back. Lint can accumulate here, inside the cabinet of the dryer, and impede or even prevent the exhaust. I've seen it happen on two different models of dryer. The dryers' thermostats prevented them overheating; thus, clothes got hot, but didn't get dry. To recap my advice, in addition to checking the vent from the dryer to the outside of the house, it is also wise to check the internal ductwork of the dryer to be sure it is also clean.
    – Eric Nelson
    Commented Mar 22 at 3:19
0

A 25 ft. run with 2, 90's (elbows) is creating vent restrictions. I would get to work on venting that dryer on the first floor if possible. A shorter, straight run may cost you a little more up front, but the energy savings is going to be huge. Also, the answer about cleaning our your dryer blower housing is a good idea also. Lint that has too much moisture builds in this spot first, just adding to your dry time.

Improve this answer

Not the answer you're looking for? Browse other questions tagged or ask your own question.