vent discharge soffit/eave options?

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Old 02-04-16, 09:01 AM
Z
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vent discharge soffit/eave options?

I want to vent a bath fan out the soffit/ under eave area. The only type of 4" outlet I can find locally is this type of cheap plastic that does not have a screen inside to keep out pests.

[ATTACH=CONFIG]62472[/ATTACH]

Can anyone suggest a higher quality option with a screen inside (or perhaps I can add) ...

What should I be using?
 
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Old 02-04-16, 09:09 AM
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There are soffit vents with screens. You just have to find them. I get them from my vinyl siding supplier. I don't recall seeing them in my big box home center.
 
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Old 02-04-16, 10:09 AM
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are you referring to soffit vent as in flush mount to vent attic or soffit vent with a 4" connector to vent fan? Im trying to vent a fan.
 
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Old 02-04-16, 01:04 PM
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This looks similar but shows a grill to keep some bugs out. I do like that they direct the exhaust out away from the soffit.
SV28 - Soffit Intake and Exhaust Vent - Primex HVAC Venting

Bud
 
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Old 02-04-16, 01:54 PM
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Another similar vent, this is listed as a dryer vent, not sure if it has a bug screen, but looks a bit sturdier.
http://dundasjafine.com/blog/

Bud
 
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Old 02-04-16, 02:09 PM
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Really bad idea.
Run the vent out a side wall or the roof.
Hot moist air gets sucked back into the attic of you have proper roof venting.
https://www.google.com/?espv=2#q=sof...O9As394RdtM%3A
 
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Old 02-04-16, 03:01 PM
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I'm going to agree with Joe on this one. The purpose of ventilated soffits is to allow for air intake into the attic space. If you are venting into that area, you are basically venting back into the attic. Now an argument can be made that 100% of the moist air will not make it back into the attic, but it still is putting warm moist air back into the attic crawl. Out the roof or through a gable wall would be optimal.
 
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Old 02-04-16, 03:09 PM
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there is no sidewall and im trying to avoid cutting a hole in the roof for the fart fan. Plus the condensation will be an issue. And with going out vertically, Im assuming if you use insulated ducting, your still going to get some condensation at the outlet point dripping back... so what do I do then? trap the condensation?


ps bud- thanks for posting those links. The second you posted was the exact one I originally purchased at the hardware store but I returned since it had no screen and wasn't all that sturdy looking. I wonder if they had the same design (which shoots its past the eves) in metal.
 
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Old 02-04-16, 04:10 PM
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I saw one that looked like the same design, MADE OUT OF COPPER. You would love it, $75. I didn't save the link.

I haven't seen anything inbetween.

Bud
 
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Old 02-04-16, 04:49 PM
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A trap for the condensation is the smart way to go. (The small amount of condensation is trapped and will eventually evaporate) Most commonly, a 4" tee and end cap is used (instead of a 90 elbow) at the point where the insulated ductwork (which should also be buried at ceiling level in the insulation) transitions to vertical.

A gable end is best, roof is 2nd best. If going out the soffit it would be smart to ensure there aren't any soffit intake vents within 4' or so to avoid recirculation. I don't know that there are any codes written on this subject. Someone correct me if I'm wrong.

Bud, is this your vent? (search for soffit vent with damper)

http://assets.ventsusa.com/media/pro...-wuedv-126.png

I've seen a few of these used. Looks less like a bat sanctuary hanging from the soffit.

https://encrypted-tbn2.gstatic.com/i...BsVQi60UxIGomj
 
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Old 02-04-16, 05:00 PM
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I've seen the casual recommendation to close vents 4' to each side, however I believe this is for vents that blow straight down from the soffit. With a 75 or 100 cfm fan with the vent cap posted, the vast majority of the exhaust air will be directed well away from the eaves. It might be prudent to cover the ventilation openings a foot to each side, but I doubt there would be a problem. If this fan will be removing moisture from showers, then the delayed timer built into the off switch would help.

Bud
 
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Old 02-04-16, 07:17 PM
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So a trap or drip leg is standard on a vertical duct? I cant picture how to put it together nor have I ever seen such a thing... sounds like a contraption.

And then what, its another chore in the winter... having to go up there and drain the thing before it overflows and damages the ceiling?
 
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Old 02-04-16, 07:56 PM
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Standard? Hardly. And you will find plenty who argue against it... and it may be a bad idea in some areas... it's not overflowing is dependant on a lot of variables, which makes it risky... using insulated ductwork, trap should be fairly close to the bath fan, buried in insulation until the vertical... as short a distance to the roof as is practical... the vent having a damper that actually CLOSES. Constant cold air coming down the ductwork in the winter is what leads to most horror stories about water dripping out of bath fans. Screw up any one of those and it could cause extra condensation and cause it to backfire. Like I said, normally the condensation is so little that it just evaporates.

They also make an actual condensation trap that needs to drain to the outside.

Here is one example I found if it suits you better.

You really can't picture a tee with a cap on one end (down) with the bath fan coming in from the side and exiting out the top? Same thing is often done on a gas/propane water heater flue.
 
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Old 02-05-16, 10:01 AM
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This is the best option! For those that say it can be sucked back into the attic they are correct if a jack leg installs them. All you have to do is seal the venting a few feet on each side.
 
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