# Dryer vent - How long is too long?



## J S Machine (Oct 6, 2009)

I bought a house last year that already had a dryer vent installed. It was a hack job, mainly the foil coil hose with some PVC pipe along the way in certain places. The laundry room backs up right to the garage. The original dryer vent came out of the wall into the garage. The previous owners bypassed this and ran the hack job plumbing to get it to the wall outside of the house. The hack job plumbing was a fire hazard and needed to be redone. 

Instead of running all that way, I bought some of the aluminum sturdy flex tubing and ran the tube to the original vent that exits into the garage. We did a load of laundry last night, and when I went out into the garage it was 95 degrees....This isn't going to work. Not only that, it is putting humidity into the garage which I cant have because I have some very expensive metal cutting machines in the garage currently which don't need any of that. We don't even open the garage on days when it rains if we don't have to go anywhere. 

I guess my question is how long is too long? I saw a video on youtube where someone was using the galvanized stove pipe looking stuff and doing it correctly (I assume). If I had to go the original route like it was, I feel like this would be the best thing to use. 

Should I use the sturdy stovepipe tubing and just plumb it back outside? This will be about a 40' run to get to the outside.


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## joecaption (Nov 30, 2011)

Yes on the solid pipe.
40' is way to long.
Can not see what you have from here, a simple drawing may help.
Anyway to run under the floor and out a rim joist to shorten the run?
Relocate the laundry room in the garage?
Just love it when I see laundry rooms in the middle of houses, looks good on paper.


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## joecaption (Nov 30, 2011)

Yes on the solid pipe.
40' is way to long.
Can not see what you have from here, a simple drawing may help.
Anyway to run under the floor and out a rim joist to shorten the run?
Relocate the laundry room in the garage?
Just love it when I see laundry rooms in the middle of houses, looks good on paper.


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## J S Machine (Oct 6, 2009)

Here's an illustration. The yellow area is all garage. The red dryer hose is the original location of the dryer vent as installed by the builder (I guess) which I hooked back up last night. The blue line basically picks up from where the red would have gone. That blue line is the hack job done by the previous owners to get it out into the garage, and run it along the wall and out of the house. This is the absolute shortest run possible. The house is a slab foundation. 

I may have exaggerated a bit. It may not be 40', but it us every bit of 30'.


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## thefixer56 (Feb 23, 2014)

The maximum safe length depends on how many 90 degree angles you have in the run. If you run it according to your drawing, you have too many angles. Here is the standard chart indicating safe lengths to use.


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## J S Machine (Oct 6, 2009)

If I run it like this, Maybe it would be ok. It won't be that great to have a tube running across the floor, but it is the only way to keep the 90 degree bends out I suppose. 










It would have the 90 coming out of the back of the dryer, the 90 making the turn to come into the garage, and then the other angles would be like 45 degrees.


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## J S Machine (Oct 6, 2009)

I should also note too, the flex hose coming out of the back of the dryer never really bends on a hard 90. I made it one big sweeping arc, but it turns a full 180 degrees to get back into the garage. I could use flex tube on the bends in the 45 areas too to minimize the sharp angles.


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## craig11152 (Jun 20, 2015)

can you come out the left side of the dryer straight in to the garage? You could eliminate some turns.


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## Oso954 (Jun 23, 2012)

What is above the laundry/garage area ? 

Even with a 2nd story there may be a route straight out thru the space between floors.

Or, you could follow the green line route hanging it from the garage ceiling. Laying it on the floor would be an invitation for problems.

I had to run my sisters dryer straight up thru a second story, attic, and out the roof. Needed a booster fan to do it. But no problems in the past 5years. In our climate, there are no snow/ice dam problems to kill that option.


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## bob22 (May 28, 2008)

What is to right of the washer?
Can you go out that wall?
Can you go up vertically and then out a roof?


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## troyks (Feb 17, 2015)

Typical dryers are designed to be vented up to 15' with two 90 degree bends, with sweeping bends they can generally vent sufficiently up to about 25', but you're still over that. The simplest solution is probably adding a booster vent for dryers, they run about $200 and generally should be installed near the exit, but can be mounted anywhere 5' away from the dryer or more. With one of these 40' with a handful of bends would be no problem.


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## md2lgyk (Jan 6, 2009)

Have you considered an in-line booster fan? I installed one in a house I once owned and it really helped.


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