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alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

Two dryers in one vent

The image above relates to my last paragraph.

With a new baby to be born in a month and my in-laws coming to live with us, we'll be a family of 6.

Since I'm building a laundry room, it will be sized to fit 2 washers and 2 dryers (Already have all of them, my units + units of previous house owners).

I don't want to have to make TWO holes in my outside wall for two vents.

Since both dryers will be next to each others, could I connect them to one vent?

A normal vent is 4" diameter has an opening of 12.57 inch^2)
If I put a 6" diameter vent I would get 28.27 inch^2.
It's more than double the 4" vent.

So I'm thinking the opening would be large enough to accomodate two dryers at the same time.

However I'm concerned that if only one dryer is operating, it would push out some of the air into the second dryer.

Would a draft stopper in the middle of each dryer exhaust tube be sufficient to resolve that problem?

Note - Forgot to include in the drawing that the end of the exhaust line is the exterior with another draft stopper.

mworks

join:2006-06-13
Faison, NC

1 edit

Don't put anything in the path of the outlet of a dryer, the reason is lint will catch on it and build up which can lead to a fire. What you want to do is join the two lines so that the airflow is like a Y so that air from each dryer will flow outward to a single pipe. You can find the fittings in the HVAC area of stores. Air likes to take the easiest path and going with the flow of a Y fitting makes it where the air doesn't want to go through the Y then back towards the other dryer. The Y fitting needs to be as close to the exit as possible.




Forgot to add that instead of using draft blockers on dryers a better solution for any home owner is to use the newer type of dryer vents that use a vertical exhaust, they block drafts and keep pest out while not causing lint issues inside the ducts.
»www.amazon.com/HEARTLAND-21000-D···_cp_hi_0


mityfowl
Premium
join:2000-11-06
Dallas, TX
reply to alkizmo

I'm not opposed to your idea here.

But if you've invested into 2 washers and 2 dryers, the question is:
Why are you cheeping out with 1 stack for 6 children?

I don't get it.



mityfowl
Premium
join:2000-11-06
Dallas, TX
reply to alkizmo

One extra whole don't matter compared to all the grief your buying.



Ken
Premium,MVM
join:2003-06-16
Markle, IN

1 recommendation

reply to alkizmo

I understand your concern with 2 holes vs 1 hole. In the US that would be a code violation, every dryer must have it's own independent exhaust and can't mix or pass through any other exhaust system. I would bet if you checked it's probably a code violation where you live as well. Even if it isn't a violation, it's still a bad idea for several reasons.

If one dryer is on, the 6" pipe is to big and will allow the air to cool and slow down. This will lead to lint build up, and moisture build up. If both dryers are on, one might overpower the other. This would cause the smaller unit to have more back pressure than it was designed for. If there was a fire, it would spread to both units. The draft stoppers are themselves another source of failure and a possible point of lint build up. I could go on, but basically the dryer exhaust is a fairly complex system with a lot of variables. Engineering your own system just isn't worth the time and effort to try and get it right versus drilling a second 4" hole and being done with it.



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to mityfowl

said by mworks:

Don't put anything in the path of the outlet of a dryer, the reason is lint will catch on it and build up which can lead to a fire. What you want to do is join the two lines so that the airflow is like a Y so that air from each dryer will flow outward to a single pipe.

Yes the easiest path, but once the main path builds up static pressure, some air will backflow to the second dryer. I don't want to make it soo humid in there.

What I could do is put a simple grill vent outside, so that there is only one draft stopper per dryer, just like a normal 1dryer/1vent setup.

As for the shortest path, it can't get any shorter than that. The dryers will be backed against an exterior wall. So we're talking about 3 feet of tubing from each dryer to the Y and maybe another 2 feet until the air is outside.

BIG EDIT

As I wrote my reply to Mityfowl, Ken have given very good arguments against using a single oversized stack.

I will make two 4" vents. Anyway even if it's on an exposed side of my house, it's also the side where we have the gaz line coming in, and the furnace exhaust pipe coming out. So two stacks there won't look too much out of place.


mityfowl
Premium
join:2000-11-06
Dallas, TX
reply to alkizmo

said by alkizmo:

The image above relates to my last paragraph.

With a new baby to be born in a month and my in-laws coming to live with us, we'll be a family of 6.

Since I'm building a laundry room, it will be sized to fit 2 washers and 2 dryers (Already have all of them, my units + units of previous house owners).

I don't want to have to make TWO holes in my outside wall for two vents.

Since both dryers will be next to each others, could I connect them to one vent?

A normal vent is 4" diameter has an opening of 12.57 inch^2)
If I put a 6" diameter vent I would get 28.27 inch^2.
It's more than double the 4" vent.

So I'm thinking the opening would be large enough to accomodate two dryers at the same time.

However I'm concerned that if only one dryer is operating, it would push out some of the air into the second dryer.

Would a draft stopper in the middle of each dryer exhaust tube be sufficient to resolve that problem?

Note - Forgot to include in the drawing that the end of the exhaust line is the exterior with another draft stopper.

That's never going to pass code.

Why put 6 or 7 lives at risk?


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

said by mityfowl:

That's never going to pass code.

Why put 6 or 7 lives at risk?

I didn't want any added risks. Ken explained the risks clearly and I now understand. (Edited my post above yours).

Another reason I didn't want two stacks is because the current laundry room is about 10 feet away from my new laundry room.
There isn't any simple way to reroute the exhaust to the old stack.

So I'd have 3 stacks within the same 10 feet section of wall!!!!

But I just thought up of a good way to re-use the hole.
The old laundry room is to be de-partitioned from the kitchen and will elongate my kitchen (Will be panties and stuff in there).

I will use the old dryer stack hole and put an in-take vent.

Why? Because I'm replacing my old range hood that only recycled the air with a 450CFM exhausting range hood. This will require an air intake from outside.


ArgMeMatey

join:2001-08-09
Milwaukee, WI
kudos:2
Reviews:
·voip.ms
·AT&T Midwest
·Time Warner Cable
reply to alkizmo

Ran across link below. Check out the instructions starting on Page 4 for multiples. You could pretty easily do the manometer check or have a HVAC shop do it for you.

Also what if you have a sheet metal shop make two half-round adapters that would use a 6" duct as a sleeve? So there would be a dedicated duct all the way to outside, although I don't know what you're using for a cap outside. It would need to be small enough that one dryer could push it open.

»www.ajmadison.com/ajmadison/item···0920.pdf

And here's the source thread:
»www.diychatroom.com/f17/anyone-r···e-51049/
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Find your USNG coordinates:
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Nick_L
Premium
join:2003-01-22
Pittsburgh, PA

2 recommendations

reply to mityfowl

said by mityfowl:

One extra whole don't matter compared to all the grief your buying.

Off topic, but this sentence makes my brain want to explode!!

mworks

join:2006-06-13
Faison, NC
reply to alkizmo

said by alkizmo:

Yes the easiest path, but once the main path builds up static pressure, some air will backflow to the second dryer. I don't want to make it soo humid in there.

What I could do is put a simple grill vent outside, so that there is only one draft stopper per dryer, just like a normal 1dryer/1vent setup.

As for the shortest path, it can't get any shorter than that. The dryers will be backed against an exterior wall. So we're talking about 3 feet of tubing from each dryer to the Y and maybe another 2 feet until the air is outside.

Code allows for multiple dryers on a single vent , it is done usually for apartment buildings or coin laundries, the requirements are pretty clear on what is required and you have covered most of it, the main one being that the exhaust piping be large enough to accommodate all dryers with little to no back pressure.

if you want to do it strictly to code then what you need is not a draft stopper but a weighted damper for each dryer. They are very similar in design but operate differently. The weighted damper uses a spring to close the damper and is required by code. It is a metal device designed to avoid the lint issues.

Cost is going to be higher because you will need 2 weighted dampers, about $20 each, and outdoor venting as well as metal ducting and the Y.


mityfowl
Premium
join:2000-11-06
Dallas, TX
reply to Nick_L

said by Nick_L:

said by mityfowl:

One extra whole don't matter compared to all the grief your buying.

Off topic, but this sentence makes my brain want to explode!!

That's cute girl friend.

Add something that matters.


Nick_L
Premium
join:2003-01-22
Pittsburgh, PA

At least you didn't spell it gurl.



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to mworks

said by mworks:

Code allows for multiple dryers on a single vent , it is done usually for apartment buildings or coin laundries, the requirements are pretty clear on what is required and you have covered most of it, the main one being that the exhaust piping be large enough to accommodate all dryers with little to no back pressure.

if you want to do it strictly to code then what you need is not a draft stopper but a weighted damper for each dryer. They are very similar in design but operate differently. The weighted damper uses a spring to close the damper and is required by code. It is a metal device designed to avoid the lint issues.

Cost is going to be higher because you will need 2 weighted dampers, about $20 each, and outdoor venting as well as metal ducting and the Y.

Well, Ken did say it can be done, but has to be very well planned out. It probably is the case for laundromats and apartment buildings (And I still see small apartment buildings that have one vent per apartment anyway).

The price of extra material wasn't really an issue. Drilling more holes into a brick wall than a typical family would need was my issue

But Ken scared me.

mworks

join:2006-06-13
Faison, NC

Are there any windows near the dryers ? There are dryer vent adapter for windows. Might be easier than going through brick.



mityfowl
Premium
join:2000-11-06
Dallas, TX
reply to alkizmo

I just wouldn't do this if I had my whole family at risk.

He didn't even say gas or electric.



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to mworks

said by mworks:

Are there any windows near the dryers ? There are dryer vent adapter for windows. Might be easier than going through brick.

Nope. It's a side... side of my house. There are no windows on the sides. However the new laundry room will be in a sectioned off part of my garage, and the garage has no floors above it. 10 feet up and you're in the attic (Yes it's a high ceiling garage). There I could drill through the vinyl wall side of the attic, but I think it's too much height to cover for venting.

said by mityfowl:

He didn't even say gas or electric.

Electric


mityfowl
Premium
join:2000-11-06
Dallas, TX

said by alkizmo:

said by mworks:

Are there any windows near the dryers ? There are dryer vent adapter for windows. Might be easier than going through brick.

Nope. It's a side... side of my house. There are no windows on the sides. However the new laundry room will be in a sectioned off part of my garage, and the garage has no floors above it. 10 feet up and you're in the attic (Yes it's a high ceiling garage). There I could drill through the vinyl wall side of the attic, but I think it's too much height to cover for venting.

said by mityfowl:

He didn't even say gas or electric.

Electric

Vent stacks or side stacks really don't matter. Run two. Why take a chance with your family?

If done correctly you'll never have to deal with a leak.


mityfowl
Premium
join:2000-11-06
Dallas, TX
reply to alkizmo

When you have a family of 6 or 7 or more you make compromises.

Sometimes things look ugly.

But they work.



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to mityfowl

said by mityfowl:

Vent stacks or side stacks really don't matter. Run two. Why take a chance with your family?

If done correctly you'll never have to deal with a leak.

Ya ya I will run two if I go forward with the project of two dryers. I will start with just one dryer and see if it suffices. However I like to keep my options open and have the information ready on hand when/if I exercise the option.

Adding a second dryer will be a major investment on another matter where I'd have to finally give in and upgrade to a 200A service.

With my 100A service, I'd only have 15A to spare if my two dryers (50A) and oven/stove (35A) run simultaenously at full capacity.

In a simple matter of timing, where all units are drawing their max amps + starting the central vac or a power tool, one of the two service 100A fuses would pop. (And that's in winter, in summer I'd have to decomission a dryer because of the AC).

Not that I'd upgrade to 200A just for the second dryer. It would be a tipping point to justify the upgrade.


mityfowl
Premium
join:2000-11-06
Dallas, TX

said by alkizmo:

said by mityfowl:

Vent stacks or side stacks really don't matter. Run two. Why take a chance with your family?

If done correctly you'll never have to deal with a leak.

Ya ya I will run two if I go forward with the project of two dryers. I will start with just one dryer and see if it suffices. However I like to keep my options open and have the information ready on hand when/if I exercise the option.

Adding a second dryer will be a major investment on another matter where I'd have to finally give in and upgrade to a 200A service.

With my 100A service, I'd only have 15A to spare if my two dryers (50A) and oven/stove (35A) run simultaenously at full capacity.

In a simple matter of timing, where all units are drawing their max amps + starting the central vac or a power tool, one of the two service 100A fuses would pop. (And that's in winter, in summer I'd have to decomission a dryer because of the AC).

Not that I'd upgrade to 200A just for the second dryer. It would be a tipping point to justify the upgrade.

Oh shit man you got a lot of problems with a family of 6 or 7.

You need to upgrade that panel.

You aren't even close to putting in 2 eclectic dryers

Good Luck


Ken
Premium,MVM
join:2003-06-16
Markle, IN
reply to mworks

said by mworks:

Code allows for multiple dryers on a single vent , it is done usually for apartment buildings or coin laundries, the requirements are pretty clear on what is required and you have covered most of it, the main one being that the exhaust piping be large enough to accommodate all dryers with little to no back pressure.

US residential building code, specifically IRC 1501.1, disallows combining a dryer exhaust with anything else. Large buildings obviously can't have a vent for every dryer, but those types of systems are engineered to take into account all the variables. My original point was it simply isn't worth the effort to engineer a system for 2 dryers just to avoid cutting a 2nd hole. Also it may or may not be allowed by code in his area.


mityfowl
Premium
join:2000-11-06
Dallas, TX
reply to alkizmo

I'm not a sparky but don't you want 15-20% excess in your panel?



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

said by mityfowl:

Oh shit man you got a lot of problems with a family of 6 or 7.

You need to upgrade that panel.

You aren't even close to putting in 2 eclectic dryers

said by mityfowl:

I'm not a sparky but don't you want 15-20% excess in your panel?

Correct that my panel (And the overhead lines) aren't of sufficient amperage capacity for two dryers, hence why I said that I'm staying with just the one dryer and that if it's delaying the laundry process too much, then I will talk with my wife about the expense of upgrading the panel (And bring forth other points promoting it, such as a heat pump upgrade being possible when we replace the furnace and AC).

I won't hook up two dryers with my current panel.

However, as it is now, the panel is fine with one dryer.

I'd have to have the dryer, oven and AC all be pulling their respective MAXIMUM circuit protection amperage rating at the same time for something like a full minute to risk popping a service fuse (Because then I'd only have 20A left per leg).

I'm not a sparky, but I believe all those appliances pulling that much amperage at the same moment for more than a minute is unlikely.

BUT I could imagine a more reasonable situation where we're at 80% load on those appliances' max circuit amperage (64A).
Then have a combination of any 120V appliances/tools that draw 10A-15A running all that once (Could be, with 4 adults) to go over the 100A limit.

We'll see what happens Those 100A service fuses are there for a reason after all. Maybe I'll buy a couple of spare ones when the in-laws arrive just in case.


mityfowl
Premium
join:2000-11-06
Dallas, TX
reply to alkizmo

Man I really hate to get involved when your close to the threshold.

Think of 4 hair dryers. About 1500 watts each.

I don't see your house carrying the load.



mityfowl
Premium
join:2000-11-06
Dallas, TX
reply to alkizmo

When I had a young family the washer and dryer never stopped.



mityfowl
Premium
join:2000-11-06
Dallas, TX

1 edit
reply to alkizmo

For about 14 years.

Day and night.

Maybe 20 years



flibby3655
Bully Spotter
Premium
join:2004-12-19
Lompoc, CA
reply to alkizmo

I tried what your talking about years ago. Sadly. it didn't work. One would give more exhaust then the other could handle and the weaker dryer thought the vent was plugged and shut the gas off. which it is designed to do if the vent is plugged. I ended up running separate lines outside and was done with it.

Hope this helps!
--
"Safe in the permanent gaze of a cold glass eye"



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to mityfowl

said by mityfowl:

Man I really hate to get involved when your close to the threshold.

Think of 4 hair dryers. About 1500 watts each.

I don't see your house carrying the load.

Ok cmon, hair dryers are like the extreme daily appliances in terms of size/wattage.

They're so light yet hungry that I have one in a box near my generator for load tests.

We've done fine with 2 adults in the house for a year at this state. And the previous owners also did fine with the same appliances for 4 years before us.

We'll see what happens with 4 adults. If the 100A fuses start to pop, I'll have an easy time convincing my wife to upgrade the service.

said by mityfowl:

When I had a young family the washer and dryer never stopped.
For about 14 years.

Day and night.

Maybe 20 years

Poopy pants.


mityfowl
Premium
join:2000-11-06
Dallas, TX

said by alkizmo:

said by mityfowl:

Man I really hate to get involved when your close to the threshold.

Think of 4 hair dryers. About 1500 watts each.

I don't see your house carrying the load.

Ok cmon, hair dryers are like the extreme daily appliances in terms of size/wattage.

They're so light yet hungry that I have one in a box near my generator for load tests.

We've done fine with 2 adults in the house for a year at this state. And the previous owners also did fine with the same appliances for 4 years before us.

We'll see what happens with 4 adults. If the 100A fuses start to pop, I'll have an easy time convincing my wife to upgrade the service.

said by mityfowl:

When I had a young family the washer and dryer never stopped.
For about 14 years.

Day and night.

Maybe 20 years

Poopy pants.

Not ever.

Women