I live in a small house built in '43. The whole neighborhood is populated by such homes built during WWII to accommodate families with the breadwinner working in steel mills and heavy industry around here. The brick ones like mine are 2 floors with a basement. There's 2 bedrooms and the only bathroom upstairs. They look and are so much alike that when I was drinking I had a florescent beer sign in the front window so I could find my way to the right place.
None of these places have ceiling vents in the bathroom so it fills with steam pretty quick and opening the bathroom window is the only way to clear the fog. If I shower i open the window. New neighbors moved in next door with 2 adults and 3-4 kids. They asked me about a fan/vent for the bathroom that doesn't require an outside vent. They don't want to go through the brick wall or roof. I believe such a device does not exist and if it did exist would be much like black majic or voodoo. But I have not kept up with such things and you never know. Is there a device that remotely resembles a non-vented bathroom fan.

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SOS USA

A dehumidifier comes to mind.

5 Best Cordless Dehumidifiers for Bathroom and Buying Guide

10 Best Dehumidifiers For Bathroom in 2020 - The House Talk

No - if it doesn't vent to the outside, you would just be pushing the humid air somewhere else in your house. If the bathroom is on the second floor, it should be relatively simple to install a vent fan and vent it either straight up through the roof.

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Regards,

Tom

My go-to company for all things fan, is Fantech. Their soffit vent will do what you ask. It vents to the underside of the soffit overhang. You just need to spec out the ducted fan for it.


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Slava Ukraini!

It needs to vent to the exterior. I’ve seen some vented into the attic,but that just saturates the insulation. They could vent it through the gable if they don’t want to go through the roof.

Mine uses the vent for the septic system . You should have a vent/s on your roof for different things . Seeing as yours is older they will probably be cast iron . Either yourself or a plumber can cut the one closest to the bathroom , put a tee in it and connect the hose from the bathroom vent to it . You'll have to have someone cut the hole in your ceiling for the vent/fan , run electric to it , but then your problem is fixed .

Some are just vented into the attic and don't go through the roof. I would not think there is enough moisture to harm anything.

Ours vents into the attic, but the house was built in 1962.

No mold or anything that would indicate it is getting wet in the attic,
but then we don't have a lot of humidity to begin with.

I can tell you after living in a house with bathroom vents dumping into the attic for 30 years that it causes no harm. Attics are vented to the outside. No mold issues at all.

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What could possibly go wrong?

Seems like you could fit one to vent out the window. Google "Vent fan for bathroom window" for a bunch of options maybe some might work for you
Steve W

There is enough moisture to cause problems in the attic, trust me on that, first hand experience.

My upstairs bathroom vents to the attic. Been that way for 36 years. I admit to being skeptical of that situation in the beginning but it has not been a problem.


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Moved into this house in 1998...was built in 1992.

First week there I noticed the bath mirrors steamed up
heavily. Took a look in attic, couldn't find the vent fans...
went back down, turned em on, went back up--could hear
em, still couldn't see em!

Turns out they were mounted, no exhaust hoses, and
buried under six inches of blown cellulose insulation.
I put some 3" dryer hose on both fans, and the steamy
mirrors no longer steamed.

A contractor told me that "code" requires either an
exhaust fan or window in a bathroom, but makes no
requirement on how the exhaust fan is ducted (or not).

I don't understand how original occupants lived there
for several years, without noticing.

New house next door has theirs's vented thru the soffit.

Vented outside with no holes in the roof. Never seen or thought about doing it that way, but it seems like a good and easy idea.

I'm guessing they'll put some kinda cover over it to keep things from getting in.

In the 70’s and 80’s vent fans would got installed in bathrooms without windows and vented into the attic.

I’ve had a couple contractor’s tell me recently that current building code requires bathroom vent fans be vented outside. Those may just be local rules though.

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Vegan by proxy.

I lived in a house that was built in 1936 and had no fans in the bathroom. I just left the door open a little bit and it helped a lot. It was great in the winter with forced air heat.

From the Florida Building Code, Residential:

Bath fans need to be vented to the outside, either thru the roof or to the soffit. Needs to be away from a window that can be opened if in the soffit.I wouldn’t suggest connecting to a plumbing vent, the risk of sewer gasses coming back into the house aren’t worth it.
Yes, in South Florida that’s what the building code requires.

... insulated exhaust piping should be used especially in cooler climate areas. Do it once and do it correctly vent to the outside. Exhaust Fans made by Panasonic run silent for a very long time, can't say that about Broan. Hopefully the information provided by many here will encourage you or change the "unvented" idea to vented outside.

With the humidity in Fl, no way I would vent anywhere else but outside.

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Sure you did

I've had the same experience in two houses - no issues whatsoever. It's not like you're pumping steam up there, it's only moist air.

My house was built in the early 1980's and both upstairs bathrooms vent into the attic. Was skeptical also when I discovered it. The roof had a ridge vent as well as the vents on each end of the house to ventilate the attic space. Recently had the roof replaced and the new roof does not have a ridge vent but a low profile automatic electric fan with thermostat control was installed to come on at 120 degrees to pull hot air out and ventilate the attic space. The roofing company said the ridge vent was not taking enough hot air out of the attic causing premature deterioration of shingles from heat.

Codes and methods are always changing.

I believe the easiest and best way to run a vent is through the eve fascia or soffit. I have two that run above the ceiling right out to the eve with a standard flapper and hood. Never caused a problem and worked for 40 years. The key is to run flexible vent from the hole in the ceiling for the new vent fan and push it out to the eve fascia. Cut a hole in the eve and find the vent pipe, connect and attach the flapper assembly to the vent pipe, then push it back into the hole. Wire the fan and done. Personally, I would insulate the vent pipe so you do not have a problem with condensation on the outside of the pipe in certain seasons.

You may run into insulation, which will require you to go into the attic and run the vent on top of the insulation or remove it to place the vent on the ceiling drywall and reinstall the insulation after done.

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Gary
SWCA 2515

Call a glazier and have him cut in an Extractor fan. I have not seen one of these in years but I had a house years ago that had one of these mounted right in the glass. It works very well and needs no electricityhttp://smith-wessonforum.com/attachment.php?attachmentid=473260&stc=1&d=1601474160

Attached Images

fan.jpg (85.8 KB, 63 views)

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NRA Range Safety Officer

Another angle on the vent fan to the outside is that it takes conditioned air from inside your home and dumps it outside, and the home makes up for that exhaust by leaking air from outside to the inside through drafts. With six occupants using that bathroom and it's exhaust fan, that's a lot of infiltrating air needing to be heated or cooled.

Perhaps a HRV (Heat Recovery Ventilator) instead of just a vent fan might be an option. They are larger and relatively expensive to purchase compared to bathroom fans, but the payback through energy savings after being used by six occupants might offset quickly because they lower the load on your HVAC equipment. They might also qualify for utility rebates and tax credits.


VHR70R ES Fresh Air Appliance - Fantech

THANK YOU ALL for all information and suggestions. I really appreciate it. I kind of thought with all the knowledge on this board I'd get some great solutions. I may print them out or email them to the neighbor and let him figure out what to do. You all are making me look like I know what I'm doing to my new neighbor.

Thanks again, Jim

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SOS USA

Before 1974 many bath fans were just ducted into the attic, In the northern climate that has become a major Black mold issue. When I worked for our cities 2nd largest slum lord we had Section Housing Authority require us to remove the mold in the attic it two buildings. The first was cleaned with a approved Bio-cyde (high priced bleach water) and then the entire surface area sealed with Bullseyes paint. After that the other build was due for a new roof, we got a one year extension and installed new decking (plywood) and new shingles. That ended up being the cheaper method.

Now days bat vents are ducted all the way out doors to the soffit or to the hat/ridge vents.

Ivan

Are you sure that is not the dryer vent? I have seen many dryer vents vented through the attic and then through the roof. Not something I would want but it is done often.

As far as venting a bathroom exhaust fan into the attic I have never seen one cause any moisture problem as they don't pull enough moisture to do harm. If you have moisture problems in the attic it is a lot more than a bathroom exhaust fan causing the problem.

Just my opinion but it seems if the fan is already ducted to the attic it's not a Herculean task to attach some piping or flexible duct to run it outside and not be concerned if the moisture is affecting the attic space.

It seems this may be more an issue in colder climates as the moisture freezes and creates frost on cold areas of the attic rather than dissipating as it would in a well vented warmer attic space.

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John. SWCA #1586

There isn't a fan or ceiling vent in their roof yet. There's no insulation in the attic, neither the floor or walls. It will get cold up there but heat lost through the bathroom ceiling should be enough to keep it from freezing.

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SOS USA

I had a bathroom remodel done. So, I got a higher CFM fan. Of course the builder put in the cheapest ones made. The exit piping was larger on the new fan, I think it went from 4 inch to six inch. It was vented through the soffit, the unit came with an adapter to reduce from 6 to 4. Didn't make sense to reduce it and restrict the flow. Got some basic duct work and ran it up to the vent ridge. I would not suggest venting directly into the attic. Might be fine, but if it isn't you are gonna have quite a mess to fix over time. Moisture is always a problem you want to prevent not fix.

If you open the link in post #25, and look at the "Accessories" tab, you'll see insulated flex duct for those cold areas.

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Slava Ukraini!

I have vented several into soffits but did a little neater job than shown. And many into the attic. Best is to take flex strait up and hang 18” -24” from
roof. If the vent tube is snaked around water will condense and end up in low spots. If severe enough you can cause a trap like effect that will act as a plug. Then you get no ventilation.

Nope, it's a bathroom vent. The laundry room is on the other side of the house. The master bath and dryer vent are also vented thru the soffit.

They almost have the house finished. Has 2 AC compressors, one it almost as tall as me and the other is a normal sized one just for the 3 car garage.

My bathroom vents and stove vent is thru the attic and out the roof.

We were just discussing a similar topic on another forum,,

Homeowner in state "A" says vent into the attic, it will be OK,,

Homeowner in state "B" says NO WAY,, MOLD!

The relative humidity in different states makes both answers possible to be true,,

Vent into an attic in coastal South Carolina, or Florida,, the moisture will destroy the structural wood in the house,,

Vent into an attic in Colorado, the moisture may actually strengthen the house!! (Just kidding, but, it is dry in CO!)

I would think the "OTHER" (PHEW!!) reason for bathroom fans would be enough to want to duct the air out of the house!!

We just open the bathroom window & turn on a small fan by the sink. The steam goes outside in a couple of minutes. We do run a dehumidifier in the winter since w/ propane heat the exhaust is hydrogen (which mixes w/ oxygen & adds a lot of moisture).

If you mix warm,moist air into cold air what do you get?
Rain,snow or condensation. I doubt it’s going to snow in the attic,but you are dumping condensation onto the wood and the insulation. Just do it right the first time. Or you can pay twice and do it again or give your buyer a discount beyond the negotiated price when you go to sell the house.Its 2020. The buyers inspector is looking for everything that isn’t up to code and/or is unsafe

Here you could probably vent to the attic, I routed mine to the soffit and when I did the addition ran the vent to a roof vent. Installing a vent through a wood roof with asphalt shingles that are in good condition isn't that hard.

Besides humidity another part of venting to an attic would be having a well vented attic.
I am thinking of running a larger vent above the stove at my place.