Exhaust fan - bathroom

[Chester11]

Not sure why I'm posting here, but some folks have a wide breadth of knowledge.

My house was built in the 70's and the baths were vented into the attic. (It's ventilated space with vents through the eaves to a roof cap). No mold, but it made me uncomfortable, so I hired a guy to route the vents to the outside.

I would have preferred it go through the roof. (Hot air rising and all). Instead the contractor ran them out the eave (so from the bathroom into the attic and down and out the eave). The vent doesn't work.

My question - who do I hire to get this right? A roofing contractor to install the vent, and then someone else to hook it up? (I'm not going on the roof - and the guy I hired originally is gone).

 

[spasm3]

Consider new fans as well. Most contractor fans are too small anyway.

 

[PimTac]

I’ve seen bathroom fans vented out through the eave. It also depends on the length of the vent pipe as well. Going through the roof is the most efficient.

If you are changing fans as well, Panasonic is the gold standard.

 

[JimPghPA]

In general the wider the diameter of the vent pipe the less restriction and reduction of flow you will have.

And in general the longer the run (distance) of the pipe the more restriction of flow you will have.

And in general the more bends in the pipe the more restriction of flow you will have.

To keep the flow good you want to keep the restrictions low.

So you want short runs, with wide pipe, with few or no bends.

If you have to make the run long, it would be a good idea to keep the pipe wide.

 

[BlueOvalFitter]

Not sure why I'm posting here, but some folks have a wide breadth of knowledge.

My house was built in the 70's and the baths were vented into the attic. (It's ventilated space with vents through the eaves to a roof cap). No mold, but it made me uncomfortable, so I hired a guy to route the vents to the outside.

I would have preferred it go through the roof. (Hot air rising and all). Instead the contractor ran them out the eave (so from the bathroom into the attic and down and out the eave). The vent doesn't work.

My question - who do I hire to get this right? A roofing contractor to install the vent, and then someone else to hook it up? (I'm not going on the roof - and the guy I hired originally is gone).

HVAC companies/contractors do these installs every day.

 

[MrHorspwer]

The vent doesn't work.

It doesn't work? What does that mean? It doesn't work because the fan doesn't turn on? It doesn't work because when you turn on the vent, your mirror is still foggy while you shower?

Venting through the eve is acceptable. It's not ideal, but it is typically to code.

As others have said: What type of fan was installed? How many cfm does it pull? How large is your bathroom? How long is the duct run? Rigid or flexible pipe? 3" or 4" duct? How many turns?

From the sound of your post, you won't be happy until you have a vent on your roof. Unfortunately, if it ends up the original guy used an undersized builder-grade Broan vent fan and you reuse it, you'll likely have the same issue.

 

[SZR48207]

Roofers in my area don't typically like vents that exhaust up.. it's something they have to work around during a reshingle and it's a possible source of leaks.. But it all just depends on how the house is built and if there is even a way to run ducting out an eave.

 

[Donald]

What does not work? I would figure that out before I decided to change the location of the vent outlet. I waited many years with it venting into the attic area. When I had my roof reshingled I gave them 2 vent housings to install on the roof.

Long vent runs can be regular (non flex) vent pipe.

 

[Wolf359]

Probably something to do with the fan. The cheap setup is to have the fan in the bathroom. If you put the fan in the attic near the exhaust, it will be much quieter but they're more money.

Inline Bathroom Fans

 

[wpod]

It would be a great time to buy a high quality bathroom fan.

 

[diyjake]

Not sure why I'm posting here, but some folks have a wide breadth of knowledge.

My house was built in the 70's and the baths were vented into the attic. (It's ventilated space with vents through the eaves to a roof cap). No mold, but it made me uncomfortable, so I hired a guy to route the vents to the outside.

I would have preferred it go through the roof. (Hot air rising and all). Instead the contractor ran them out the eave (so from the bathroom into the attic and down and out the eave). The vent doesn't work.

My question - who do I hire to get this right? A roofing contractor to install the vent, and then someone else to hook it up? (I'm not going on the roof - and the guy I hired originally is gone).

Good thing you don't have mold. Stupid way of doing things but a lot houses in PA are set up this way .

 

[barryh]

The problem is than normal in line axial fans are hopeless once attached to any length of ducting as they can't create sufficient differential pressure to overcome the extra resistance.

What you need is called a mixed flow fan which is a cross between centrifugal fan and an axial fan. These are designed to produce a decent differential pressure and will shift many times more air than an axial fan. I'm looking to buy one right now for a bathroom refit.

 

[TonyTriumph]

I don't like venting up through the roof. 1) Condensation will run back down the pipe 2) Every hole in the roof is a potential leak.
Best IMO is to have a good Squirrel cage type fan (70's era fans were mostly noisy AND pathetic) then vent it first up, then sloping slightly down with rigid pipe to and eve or soffit vent. Keep the run as short as possible.

 

[BISCUT]

I built my house ground up in 2004. I ended up with one single main stack and therefore only 1 hole in my roof. Fireplace has it's own chase. Two of the bathrooms vent out the soffit via flexible duct. I was concerned with moist warm air in the below freezing winter temps we get October through March. Has not been an issue in 16 years.

For me I'd rather keep holes from my roof but I get your wanting the comfort you may feel from having each vent run through the roof.

 

[sloinker]

They sell inline helper fans for clothes dryers. Give it a thought. Venting into the attic was common practice since bathroom vent fans were invented until recently.

 

[JC1]

Not sure why I'm posting here, but some folks have a wide breadth of knowledge.

My house was built in the 70's and the baths were vented into the attic. (It's ventilated space with vents through the eaves to a roof cap). No mold, but it made me uncomfortable, so I hired a guy to route the vents to the outside.

I would have preferred it go through the roof. (Hot air rising and all). Instead the contractor ran them out the eave (so from the bathroom 8 the attic and down and out the eave). The vent doesn't work.

My question - who do I hire to get this right? A roofing contractor to install the vent, and then someone else to hook it up? (I'm not going on the roof - and the guy I hired originally is gone).

O

 

[Chester11]

Thanks for the replies - the fans are about 15 years old and definitively a big part of the problem. They need to be replaced - but the plan was to renovate anyway, so this was a stop gap fix just to prevent mold. (Paint in the one bath is peeling, and rust is forming on the cheap bathfitter hardware installed by the previous owner). The renovation has been delayed.

These are the world's smallest bathrooms - shower and small sink. The vent is 3 inch steel up to a flex tube out the eave. The run is about 6 foot max. (The bathrooms abut each other and the fans go into a shared vent).

I do have a new fan - but was hoping to deal with all the blown-in insulation mess once during the renovation. (Also trying to make the fan fit in the existing opening.) Maybe next month when it cools down a bit.

 

[JLawrence08648]

Electricians install bathroom fans.