Do I need a soffit grille for exhaust?


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Old 08-29-21, 09:56 AM
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Do I need a soffit grille for exhaust?

Hello, I am in the process of a master bath remodel, which includes a new 100 CFM exhaust fan. The bath is on an exterior wall and I have cut an opening above the (new, lowered) ceiling to access the soffit for the fan's exhaust. The soffit consists of metal (steel, I assume) panels with continuous stamped louvers, and there are no obstructions in the soffit from what I can see. My intent was to cut an opening in the metal to accommodate a soffit grille and duct to it, but it occurs to me that this may be redundant, since the soffit is so well ventilated already. Would it be acceptable to just terminate the exhaust duct into the soffit and call it good? (We are in a rural area so there won't be any inspections.) I live in cold country (Wisconsin), so of course I'm concerned about wintertime condensation, icing, etc.

If I do need a grille, I want it in stainless steel, not plastic, so what's a good source for something like that?

Thanks for any advice.
 
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Old 08-29-21, 11:47 AM
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Would it be acceptable to just terminate the exhaust duct into the soffit and call it good?
No. You need to install a soffit exhaust fan vent. The vents on the soffit are for the intake of air up into the attic which then exhausts out the roof vents or ridge vent. Due to this, you are also better off venting an exhaust vent through a roof.

Soffits are typically aluminum or plastic. I have never seen a stainless steel soffit vent, only plastic, and aluminum.
 
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Old 08-29-21, 11:55 AM
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Lots of options but dont just lay it there, the moisture get into the attic, plus you want to insulate that duct so that condensate does not form and flows back into the fan!


 
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Old 08-30-21, 12:55 PM
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Thanks to both for the advice. Yes, the duct will definitely be insulated; the existing ceiling was completely ruined due to uninsulated exhaust ducting from the bath.

Tolyn, you are correct of course, I had not considered that the actual flow is INto the vents (head-smack). I understand about it being best to go thru the roof, however I am hesitant to do that due to the amount of snow we get here and that I do frequently pull the snow off the roof - don't want another obstruction that I'm likely to damage. An aluminum vent will be OK, I'll do some searches.
 
 

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