Addressing a clothes dryer issue I disassembled and cleaned out the venting apparatus as best I could. In doing so, I noticed the exhaust vented upward, behind the wall, presumambly to the roof (the dryer is located on the second floor of a two-story house. It appears as though the builder could have just exited it sideways directly to the house exterior. Anyway, I thought this routing a bit unusual as the lint would not as easily exit the venting. Am I wrong on this? BTW, it’s relatively new construction.
By directly outside, do you mean the dryer is against an outside wall or that it would be a short horizontal run to get outside?
If the former, I agree that seems odd. If the latter, I think it would be difficult to route it horizontally through the wall given that it is as wide as the wall studs it needs to go through.
“By directly outside, do you mean the dryer is against an outside wall or that it would be a short horizontal run to get outside?”
Yes, the unit is indeed on an outside wall. Really seems odd it would be routed elsewhere. If nothing else, it would have been a much shorter run, to say nothing of going through the roof. There were a couple hundred homes built the same and nobody seems to have a problem. Would seem to me that lint would have a tendency to drop back toward its source.
most lint should be filtered before leaving the dryer. a vent pipe too long or necessarily vertical would collect lint that passed and be a fire hazard and strain on the dryer.
some people hate the look of utility systems in the house and builders might try to hide them. one less vent out the house even if it doesn’t work as well.
Can you determine where it exits the house, or even that it exits at all? I’d be concerned that it’s venting into the attic. You wouldn’t want the humidity from a dryer in your attic.
Anecdote: We bought our house from the builder. During the warranty period, I noticed the basement bathroom vent just went into the joist space, but never exited the house. The manager was skeptical when I reported it, until he came and looked for himself. They added a vent run. The relevant point is, builders make mistakes. Perhaps your vent is supposed to exit straight out the wall, but they forgot, and it just vents into the wall. This is even worse than venting into the attic.
Either way, you really should verify that it does actually vent out of the house.
There should be a small 4x4 vent to the outside. Either on the roof or on an exterior wall. Made of Plastic or Galvanized steel, with a bird screen or baffle on it.
Venting into the wall or attic is against codes.
There should be a filter prior to going into the wall, otherwise the screen at the end will become clogged and the dryer wont work very well.
( I installed these in my AC days )
I was just thinking, if you know which other homes are the same model as yours, you could look at them from the outside where the vent would be if it went straight out the wall. If they have vents, your house probably should too. If they don’t, it’s more likely your house is OK, but I (personally) would still want to know where the vent leads.
I wouldn’t think adding a hole to vent straight out the wall would be very hard.
I would immediately inspect the attic to make sure the exhaust air is vented to the outside because it’s amazing what kind of shortcuts occur during construction. Regardless, forcing the dryer to push the air/lint vertically for 8’ or more is just plain dumb. Reroute the line to the nearest exterior wall and install a proper exterior dryer vent. When it comes to dryer exhausts, the shorter the run and fewer 90 degree bends, the better the system will function.
Having a long vertical run is also bad because, depending on the ambient temperature, moisture can condense inside the duct and then run down inside it, leading to a pool of water where your probably don’t want it.
Thanks for the input. I do believe it’s best to find out for sure where the venting is terminated.
Just as a data point, I have a dryer in the basement against the outside wall and vent it directly to the exterior, giving it about a 10-foot run before it exits the house (to clear the grade and a slight lateral move).
I believe this to be the preferred set-up due to the concerns expressed above.
As I remember, it’s not allowed to be horizontal, only vertical, when behind walls. With minimal angle.
I used thermofin (flexi metal ducting) at the time, to the roof. There was a max height also, probably 20 ft.
I remember splicing 10ft sections of them on occasion in custom homes, from second floor to gable roof.
The first floor ones went directly out the side. Too far to roof.
That shouldn’t be too difficult. With a load of damp clothes in the drier while it’s running, on a cool night you should be able to see some ‘steam’ coming from the vent.
What pushing? It’s hot air, it will naturally rise. Of more concern is that as it rises, it will meet a cold vent pipe, or cold outside air, and condensate might drip back down your vent pipe and puddle somewhere. So do try to reroute it if possible.
Yes, it’s hot air and hot air rises but at a speed that’s insufficient to exhaust the moisture laden air/lint. A simple experiment would be to disconnect the dryer exhaust fan and allow simple physics to vertically exhaust the hot air and see how long it takes to dry the clothes before the lint ignites at the dryer exhaust port.