Bathroom fan exhaust vent

[buckeyefarmer]

Inspector got me for venting bathrooms to soffit when i built in 1997.

It is a national code, not everyone follows it.

 

[EddieWalker]

I can see where venting to the soffit would create issues. That's where the air enters the attic. Running the vent duct up high to the ridge vent is what I see done in a lot of houses that I work on. This way the natural air flow carries the moist air out of the attic.

 

[TractorGuy]

The ones in my single story house are ducted up just under the ridge vent of the roof. I have considered replacing them with a remote version that isn't as noisy but it just doesn't ever come up on my list.

 

[teejk]

I can see where venting to the soffit would create issues. That's where the air enters the attic. Running the vent duct up high to the ridge vent is what I see done in a lot of houses that I work on. This way the natural air flow carries the moist air out of the attic.

I've seen the vent piping terminate into the attic also, I'm sure code says it has to be carried outside and worse yet I think each fixture has to be on it's own )other than a whole house unit). That can be a lot of holes. Introducing moisture into an attic space in cold climates can allow it to condense on the underside of the roof sheathing. It also lowers the effectiveness of insulation.

 

[dmccarty]

Our fans are vented out of the roof. We used Panasonic fans for the bathrooms and I think the attic fan as well.

The bathrooms have a little room for the toilet. The inspector made us put in fans in that little toilet space. We used cheap contractor fans to meet code but seldom use them but we do use them from time to time....

The only problem with the Panasonic fans is that they are VERY quiet. :shocked::laughing::laughing::laughing: Which is why we bought them. The problem is you can leave them on and forget about them. So, sometimes we turn on the noisy fan to remind us to turn off the Panasonic fan. :laughing::laughing::laughing:

No way would I vent our bathroom to the attic or any other closed space. When it gets really cold the shower vent will sometime condense water vapor which then drips from the vent. No way would I want that moisture in my attic.

Later,
Dan

 

[CMV]

Do the panasonic fans have lights too?

In the little toilet closet the light & fan are separate. But the main bathroom area has vanity lights over a 6' sink counter as the primary lights and a small ceiling light (one bulb fixture) at one end, then the vent by the shower in ceiling at other. One reason I chose this vent/fan was it had a light fixture too which helped a lot.

Sad it only lasted a few years before rusting & looking crappy. It wasn't cheap, but not top of line. Hunter brand I think. Kohler maybe? Something from Lowe's or HD...but not the cheapest there by any means.

Quiet would be nice. But needs a decent light fixture also....

 

[dmccarty]

Do the panasonic fans have lights too?...

Our Panasonic exhaust fans do not have lights but they might have models that do.

Later,
Dan

 

[buckeyefarmer]

put a night light bulb in this one.
I posted installation pics on TBN a few yrs ago when i installed this fan.

 

[teejk]

Our fans are vented out of the roof. We used Panasonic fans for the bathrooms and I think the attic fan as well.

The bathrooms have a little room for the toilet. The inspector made us put in fans in that little toilet space. We used cheap contractor fans to meet code but seldom use them but we do use them from time to time....

The only problem with the Panasonic fans is that they are VERY quiet. :shocked::laughing::laughing::laughing: Which is why we bought them. The problem is you can leave them on and forget about them. So, sometimes we turn on the noisy fan to remind us to turn off the Panasonic fan. :laughing::laughing::laughing:

No way would I vent our bathroom to the attic or any other closed space. When it gets really cold the shower vent will sometime condense water vapor which then drips from the vent. No way would I want that moisture in my attic.

Later,
Dan

I've heard stories about "rain" in attics if the fans are not vented outside particularly in cold climates. Never a good thing (mold, detriment to insulation value, destruction of wood sheathing and framing members, etc.). We planned this house ourselves and my HVAC guy and I concluded that a whole house system would work. Being in a freeze/thaw climate, I personally hate penetrating the roof any more than I have to. Each bathroom (and the kitchen) would direct to a single unit in the basement that then exhausts out of 1 hole (6" round transitioned to 8" oval) in the sidewall. That was all done before the sheet-rock went up. Would be hard to retro-fit because the vent flex piping and wiring for independent timer switches had to be in place and dropped to the basement for the eventual connections. In your case, you can certainly add timers to replace your fan switches...old fashioned types like on a pizza oven (tick, tick, tick) or for a bit more money some now come with humidistats.

 

[ray66v]

I have seen an attic full of mold from the bath fans venting into it.

It has a lot to do with how many people shower, how often, and how long they shower, how dry you keep your house, how well the attic is vented, and the weather in your area.

You can get away with it for years, under the right conditions.

Venting a bath with no shower into an attic, isn't necessarily going to cause a big problem either.

But, putting moisture in the wrong place can be an expensive lesson.

I would find a way to run a duct to the outside.

And, I would highly recommend the previously mentioned back draft damper be installed as close to the fan as practical. If it is a long run, or has more than 2 bends, I would up size it to 6", or possibly bigger if that's what you started with. If not, you may lose airflow.

Install a push button timer in place of the fan switch, and you can forget about having to remember to turn the fan off.

 

[RoyKing]

Exhaust fan's are problem in today's tight houses with central air. If your AC duct work leaks at all and is in attic. Then house will be under negative pressure unless the AC Return has fresh air vent. So your exhaust fans often just vent outside air in, probably why many just vent in the attic. Many have flap vent on top but become inoperative with age. Mold in your attic probably caused by something other bath fans.

 

[kcflhrc]

Duct work in the attic must be a Florida thing. You don't see that in cold climates.

 

[ultrarunner]

Not surprising. I found one not vented to the outside when I remodeled my house. Took a bit of work to snake a vent through and fix it. As an aside, when we remodeled we took the contractors advice and got Panasonic vent fans. They are almost silent and well worth it. I cringe every time I go into an expensive house and hear the economy grade fans.

I wonder if Panasonic Fans would work to move warm air created from a wood stove?

 

[3Ts]

The only problem with the Panasonic fans is that they are VERY quiet. Which is why we bought them. The problem is you can leave them on and forget about them. So, sometimes we turn on the noisy fan to remind us to turn off the Panasonic fan.

Replace the switch with a timer. (as has been mentioned in several posts)

 

[dmccarty]

Replace the switch with a timer. (as has been mentioned in several posts)

Not really needed and a bit overkill since we don't use the fans that often. We do have a built in space heater in the bathroom which is on a timer.

Later,
Dan

 

[ray66v]

So your exhaust fans often just vent outside air in, probably why many just vent in the attic. Many have flap vent on top but become inoperative with age. Mold in your attic probably caused by something other bath fans.

Exhaust fans always cause outside air to be drawn into the house. If you push air out, other air has to come in somewhere to replace it.

Whether people realize it or not, doors and windows leak substantially more air than normal bath fans can draw.

In the example I mentioned, the mold was from the bath fans. The mold was worst where the vents were.

And, venting them to the outside, has kept it from returning after it was removed.

The reason builders vent into the attic, is simple cost cutting.

 

[BAP]

One without rats, bats, or squirrels I guess. :laughing:

You forgot the mice.

 

[buckeyefarmer]

Duct work in the attic must be a Florida thing. You don't see that in cold climates.

Sure you do, very common. Just insulate.

 

[ultrarunner]

Duct work in the attic must be a Florida thing. You don't see that in cold climates.

Standard here in California too... at least the SF Bay Area.

 

[CMV]

Mine looks like a great big silver octopus sprawling thru the attic. Very common around here to be slab foundation, HVAC & ducts all in attic