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Old 02-08-2019, 05:04 PM   #16
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Re: Exhaust fans venting through soffit


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Originally Posted by Bud9051 View Post
Picture of the soffit area on the outside Bud
Photo is attached
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Old 02-08-2019, 05:46 PM   #17
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Re: Exhaust fans venting through soffit


Thanks.
Those don't look like they are soffit vents but even if they are they are pointed in the wrong direction. This is a soffit vent, there are others, but they direct the sir flow down and away from the house. The air next to the house is already a bit warmer so being pushed up to the soffits. You need to get the exhaust air away from that flow and the house.

That could help.

Bud
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Old 02-12-2019, 09:24 PM   #18
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Re: Exhaust fans venting through soffit


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Originally Posted by Bud9051 View Post
Thanks.
Those don't look like they are soffit vents but even if they are they are pointed in the wrong direction. This is a soffit vent, there are others, but they direct the sir flow down and away from the house.

Bud
I've been monitoring my soffit vents following showers, etc. and there is quite an accumulation of frost on the adjacent soffits vents. It's pretty clear that humid air is getting sucked back up into the attic. I've looked at all the options of proper soffit vents, including the ones in the picture below but they all don't extend very far. Is there a way to add an extension to the exhaust vent somehow so that it extends past the edge of the eaves and expels any moist air away from this area?
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Old 02-13-2019, 02:10 AM   #19
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Re: Exhaust fans venting through soffit


Good morning, I'm up checking the progress of our snow storm so not really awake.
I have not seen soffit terminations that extend farther out as you ask, but I noted that what you have is rather close to the house to start. If a new vent could be located as far out as possible the extra distance towards the eaves would work in your favor.

However, just directing the air flow down and away as the vents pictured are doing might be sufficient. I like the first one.

In addition I have seen installations where the soffit intake vents to each side of the exhaust vent are blocked, 6" or so.

In general exhausting out the soffits is not the best, but there are occasions when other locations are exceedingly difficult, thus they make vent terminations available.

Best for now. Kick it back if I did not answer your questions.
Bud
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Old 02-13-2019, 08:01 AM   #20
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Re: Exhaust fans venting through soffit


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Good luck with insulation sleeves. There is no heat source to keep the pipe from becoming the same temperature as the attic until you punch the exhaust fan button to send warm moist air through that pipe. That's too late being condensation is immediate and will continue unless the room air will increase pipe temperature to above and beyond dew-point temperature.

I continually see this through the roof recommended but no one seems to have an answer to water problem.
Actually there is a heat source, it's the air escaping from the home out the vent continuously all day 24/7/365.

The exhaust fan is basically just an open hole in the ceiling. Sure, there may be a damper in the line, but it's not air tight.
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Old 02-13-2019, 08:04 AM   #21
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Re: Exhaust fans venting through soffit


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So, what are my options?? If rerouting through the roof is not feasible, can I add a sheet of foam board in the vulnerable area(s) to discourage condensation?
Why is rerouting through the roof not feasible?
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Old 02-13-2019, 08:10 AM   #22
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Re: Exhaust fans venting through soffit


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Actually there is a heat source, it's the air escaping from the home out the vent continuously all day 24/7/365.

The exhaust fan is basically just an open hole in the ceiling. Sure, there may be a damper in the line, but it's not air tight.
You better get puckered up to go on the roof and chip ice from the vent. Next
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Old 02-13-2019, 01:41 PM   #23
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Re: Exhaust fans venting through soffit


I wanted to get my two bathroom vents off the roof when I got my roof replaced a year and a half ago. Reasoning was different, though. I wanted fewer holes in the roof that could cause leaks. There was a cosmetic piece to it as well - I really dislike when solar panels have to put around vents in a blocky way - messes with my OCD I think :-) So I wanted a good big stretch of open space for some future solar without vents in the way.
I routed mine out the side of the house.
They're about 2-2.5' under the eaves - that's about as far as I could go down with them. The thinking was that the vent flap would then direct the moist air out and down a bit. The exhaust ducting... I don't think I left much of a dip in it to catch any moisture, but I have extra ducting length scrunched up, so I could probably add a little dip in it. I think it only has about a foot rise over about 6-8' run. I'm in SoCal - so extreme cold temps aren't much of an issue here.
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Old 02-13-2019, 02:26 PM   #24
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Re: Exhaust fans venting through soffit


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You better get puckered up to go on the roof and chip ice from the vent. Next
Next? Next what exactly? Often times folks laugh at what they are ignorant about.

Are you aware that most bathroom fans that are vented... vent up through the roof?

It's the "absolute best way"... some folks say... like this guy: https://www.todayshomeowner.com/vide...n-in-an-attic/

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Old 02-20-2019, 08:04 AM   #25
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Re: Exhaust fans venting through soffit


ok, so here's a new one. It's freezing cold this morning, -25C, and I noticed frost around one of my soffit exhaust vents, BUT it hasn't been turned on in over 12hrs. Does this mean I have air leakage?
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Old 02-20-2019, 08:15 AM   #26
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Re: Exhaust fans venting through soffit


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ok, so here's a new one. It's freezing cold this morning, -25C, and I noticed frost around one of my soffit exhaust vents, BUT it hasn't been turned on in over 12hrs. Does this mean I have air leakage?
You have a flapper vent at the fan and maybe one at the outlet but they do not seal tight so you will always have some leakage and the ice is the house moisture that is freezing.
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Old 02-20-2019, 08:59 AM   #27
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Re: Exhaust fans venting through soffit


I can't tell from the picture but do your current exhaust vents have flappers to close them. To me they look like vertical style vents not intended for horizontal applications. If you look at the first image on post #18 you will see gravity would be working for you. Of course it might just freeze shut but that wouldn't be terrible and would go away when the temp picks up.

What style flapper is on that vent?

Bud
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Old 02-20-2019, 10:26 AM   #28
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Quote:
Originally Posted by Bud9051 View Post
I can't tell from the picture but do your current exhaust vents have flappers to close them. To me they look like vertical style vents not intended for horizontal applications. If you look at the first image on post #18 you will see gravity would be working for you. Of course it might just freeze shut but that wouldn't be terrible and would go away when the temp picks up.

What style flapper is on that vent?

Bud
I'm not entirely sure. My plan was to replace all exhaust vents with backdraft dampers. Would this address the air leakage issue, both inside and out?
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Old 02-20-2019, 11:26 AM   #29
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Re: Exhaust fans venting through soffit


The damper pictured in post #18 looks to have a damper designed to close in a soffit installation plus it directs the humid aid down and away from the house/soffit. If this is what you are referring to I do think it will help.

fan pressure can move a damper out of the way, but natural air pressure (called stack effect) has almost no pressure so just the weight of that damper should keep it closed. But they are not perfectly sealed. Should be an improvement.

Bud
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