Piggy backing exhaust vents
#1
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Piggy backing exhaust vents
My clothes dryer is located in the basement and is vented outside with 4 inch galvanized duct run approx 20 feet long.
I am building a darkroom (photographic silver print wet darkroom) this winter and would like to piggy back the vent exhausts.
Would there be an issue with installing a wye in the dryer duct run and and adding an exhaust fan from the darkroom so they share the last 8 feet or so of the run?
I am building a darkroom (photographic silver print wet darkroom) this winter and would like to piggy back the vent exhausts.
Would there be an issue with installing a wye in the dryer duct run and and adding an exhaust fan from the darkroom so they share the last 8 feet or so of the run?
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Thank you Mitch,
A while back I looked in to piggy backing the kitchen and the bathroom to save one wall penetration and it came back as not recommended too, I guess I just have to come to terms with one exterior vent per use.
Have a good weekend,
A while back I looked in to piggy backing the kitchen and the bathroom to save one wall penetration and it came back as not recommended too, I guess I just have to come to terms with one exterior vent per use.

Have a good weekend,
#4
I guess I just have to come to terms with one exterior vent per use.
#7
That is correct. About the only time you can have a single outside vent is when you have multiple bathrooms connected to a single remote exhaust fan and that fan has a single vent.
Next year I plan on remodeling this bath (shower only) and was debating about putting a vent through the wall to the outside or tapping into the vent that is right next to it.
#8
Norm, as Furd mentioned in his post, you need a remote inline fan- to power the suction from both vents. They are also quiet. You don't hear the whirling inside the bathroom.
Remote In-Line Fans - Bath and Ventilation Fans - NuTone
Remote In-Line Fans - Bath and Ventilation Fans - NuTone
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Thanks guys, point is taken.
Indeed, dust is the ultimate enemy!
Furd
That is correct. About the only time you can have a single outside vent is when you have multiple bathrooms connected to a single remote exhaust fan and that fan has a single vent.
That is correct. About the only time you can have a single outside vent is when you have multiple bathrooms connected to a single remote exhaust fan and that fan has a single vent.
pugsl
Even without the dryer heat venting into room, dryer vents also carry a lot of lint which I would not think good for your prints.
Even without the dryer heat venting into room, dryer vents also carry a lot of lint which I would not think good for your prints.

#10
So, if I have back to back bathrooms and want to add a vent fan to the bath that borders an outside wall (hence no vent to begin with) I can't tap into the existing vent pipe in the attic crawl space? It's only water vapor and only draws air out and up. What is the problem?