# Clothes Dryer Exhaust - Makeup Air



## Dominic (Dec 18, 2019)

Section 504.6 states "_*Makeup air*. Installations exhausting more than 200 cfm (0.09 m3 /s) shall be provided with makeup air."_

The laundry room I am designing will have 3 dryers which triggers 504.6.  The engineer is telling me there is no off the shelf make-up air unit so he will need to design one.  His design would be variable speed and tied to the quantity of dryers running.  This is an expensive little sytem for a 3 dryer laundry room.

Has anyone run into and has an economical solultion?  

There is an opperable window in the room.  Can we say the window is our point of make-up air?  Code does not specifically state mechanical means of makeup air.

I am interested to see how others dealt with this.

Thank you in advance.
_
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## cda (Dec 18, 2019)

What kind of setting
House, apartment, business,    other?

one story or multi ?


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## Dominic (Dec 18, 2019)

cda said:


> What kind of setting
> House, apartment, business,    other?
> 
> one story or multi ?


One Story.


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## Dominic (Dec 18, 2019)

Dominic said:


> One Story.


Its a 700 s.f. addition to a row house apartment building.


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## cda (Dec 18, 2019)

Run an open butt pipe to outside?


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## Dominic (Dec 18, 2019)

The window is operable.  Can we say makeup air is through a window?


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## ADAguy (Dec 18, 2019)

Consider a louvered door or through the wall?


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## e hilton (Dec 18, 2019)

Dominic said:


> The window is operable.  Can we say makeup air is through a window?


Only if you can guarantee that the window will be opened when the dryers are running.  Good luck with that.


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## Dominic (Dec 18, 2019)

ADAguy said:


> Consider a louvered door or through the wall?


Threee sides are exposed to the exterior and the 4th wall is shared with an apartment.


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## steveray (Dec 18, 2019)

https://na.panasonic.com/us/home-an...uality/ventilation-fans/whisperfresh-selecttm


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## Dominic (Dec 18, 2019)

steveray said:


> https://na.panasonic.com/us/home-an...uality/ventilation-fans/whisperfresh-selecttm


This would be perfect if there was a pre-heat option.


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## e hilton (Dec 18, 2019)

Dominic said:


> This would be perfect if there was a pre-heat option.


So you’re ok with simply opening the window to admit fresh air, but you have a problem with a device that doesn’t preheat?


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## Dominic (Dec 19, 2019)

I am not ok with the window option. The ventilator is a good solution. Just trying to find a perfect solution.  

I think the best solution is to install heat pump dryers and call it a day.


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## e hilton (Dec 19, 2019)

Dominic said:


> I am not ok with the window option.


Maybe, maybe not.  More than once you proposed that solution.


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## cda (Dec 19, 2019)

Ductless a/c? Just for that room


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## e hilton (Dec 19, 2019)

cda said:


> Ductless a/c? Just for that room


That would control the room temperature, but do nothing for makeup air.


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## Mech (Dec 19, 2019)

I would say you still need some sort of control system to start and stop the fan(s) with the dryers, unless you rely on the occupants using the dryer to start the fan(s).

Without conditioning the outside air, you could be drastically raising or lowering the air temperature and raising the humidity of the room.


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## steveray (Dec 19, 2019)

ERV or HRV?


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## rgrace (Dec 19, 2019)

Assuming these are electric clothes dryers and makeup air is the only issue ....

Here's my thoughts .... provide exterior wall opening and a motorized damper (sealed well so we don't offend the energy folks too terribly much). Interlock each dryer to the motorized damper so if one operates, damper opens. Provide electric unit heaters to keep temps up during the winter. A/C wouldn't be required or necessary in the summer, at least not for the functionality of the clothes dryer. If you want comfort, you could provide A/C. Make sure walls are well insulated


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## Pcinspector1 (Dec 19, 2019)

Consider a louvered door!


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## Msradell (Dec 19, 2019)

rgrace said:


> Assuming these are electric clothes dryers and makeup air is the only issue ....
> 
> Here's my thoughts .... provide exterior wall opening and a motorized damper (sealed well so we don't offend the energy folks too terribly much). Interlock each dryer to the motorized damper so if one operates, damper opens....


I like the motorized dampers idea but why not go one step further and have them operate based on pressure differential between the room with the neighboring room/hallway? It probably would necessary to provide makeup air if only 1 of them was running.


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## ADAguy (Dec 20, 2019)

Pcinspector1 said:


> Consider a louvered door!


 
Previously suggested (smiling).


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## Yikes (Jan 7, 2020)

I live and design in a mostly temperate climate (southern California).  Most of the apartments developers I work with make the common laundry room an unconditioned space.  they put a barometric backdraft-style louvered damper on the exterior wall and they're done.


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## AHJwalker (Jan 7, 2020)

Is there a knockout anywhere on the dryer that would accept a 4" intake pipe?


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