Bathroom fan
 

I have an older home that I want to install a bathroom fan into. Is it ok
for the exhaust air to duct into the attic, or must it be ducted to to the
outside of the house through the wall. If it can just be ducted into the
attic it will save a lot of effort.I can't imagine a small amount of
moisture messing up the attic.

Tom

Tom Edelbrok wrote:
I have an older home that I want to install a bathroom fan into. Is
it ok for the exhaust air to duct into the attic,

No.

It is not OK. I can cause serious damage in the attic. Warm moist air
up there can do a number of very bad things. You want the fan to move that
moisture out of your home, not just move the problem to a different part of
your home.


or must it be
ducted to to the outside of the house through the wall. If it can
just be ducted into the attic it will save a lot of effort.I can't
imagine a small amount of moisture messing up the attic.

Tom

--
Joseph Meehan

26 + 6 = 1 It's Irish Math

If you had done a search for bathroom fans or ventilation within this
group, I'm sure you would have found a number of strings discussing
your issue.

Mr. Meehan has summarised the issue nicely.

Tom Baker

The first two respondents took care of the "where to vent" question. I'll
add this: There are a few different sizes of fans for bathrooms. It makes no
sense. Get the one that moves the most air. Don't even think about noise
level. When you finish your shower and the bathroom's almost totally devoid
of steam, you'll be glad for the noise of the fan.

"Tom Edelbrok" wrote in message
news:_shDd.34659$nN6.29239@edtnps84...
I have an older home that I want to install a bathroom fan into. Is it ok
for the exhaust air to duct into the attic, or must it be ducted to to the
outside of the house through the wall. If it can just be ducted into the
attic it will save a lot of effort.I can't imagine a small amount of
moisture messing up the attic.

Tom

Doug Kanter wrote:

...When you finish your shower and the bathroom's almost totally devoid
of steam, you'll be glad for the noise of the fan.

It's more energy-efficient to finish the shower, then turn on
the fan switch, and let a humidistat turn off the fan.

Nick

wrote in message
...
Doug Kanter wrote:

...When you finish your shower and the bathroom's almost totally devoid
of steam, you'll be glad for the noise of the fan.

It's more energy-efficient to finish the shower, then turn on
the fan switch, and let a humidistat turn off the fan.

Nick


Probably, but at that point, your walls are soaked. Not good for wallpaper
(if any), no matter WHAT the manufacturer claims about it being made for
moist environments.

wrote in message
...
Doug Kanter wrote:

...When you finish your shower and the bathroom's almost totally devoid
of steam, you'll be glad for the noise of the fan.

It's more energy-efficient to finish the shower, then turn on
the fan switch, and let a humidistat turn off the fan.

Nick


I think this is a bad plan. Better to vent the steam directly from the
shower stall and leave the bath room dry. They make fan light combinations
that are rated for over the tub use.

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.

Tom Edelbrok wrote:

I have an older home that I want to install a bathroom fan into. Is it ok
for the exhaust air to duct into the attic, or must it be ducted to to the
outside of the house through the wall. If it can just be ducted into the
attic it will save a lot of effort.I can't imagine a small amount of
moisture messing up the attic.

Tom

First of all is this bathroom used for showers?
If not, you can definitely vent in the attic.
If so, in spite of all oter advice, it would appear to depend on the
attic venting and how well the attic is insulated. We have a fan in a
bathroom used for showers that vents into the attic and have had no
problems. House is now 40 years old. As usual YMMV.

LB

Pop wrote:

It's more energy-efficient to finish the shower, then turn on
the fan switch, and let a humidistat turn off the fan.

I disagree.

Why? Say 1.25 gpm of 105 F water comes out of the shower for 10 minutes,
and the bathroom air is 70 F at 50% RH to start with, and we a) run a
50 cfm fan during the shower and afterwards until the bathroom reaches
60% RH, or b) run it afterwards until the RH reaches 60%...

Nick

wrote in message ...
Tom Edelbrok wrote:

I have an older home that I want to install a bathroom fan into. Is it ok
for the exhaust air to duct into the attic, or must it be ducted to to
the
outside of the house through the wall. If it can just be ducted into the
attic it will save a lot of effort.I can't imagine a small amount of
moisture messing up the attic.

Tom

First of all is this bathroom used for showers?
If not, you can definitely vent in the attic.
If so, in spite of all oter advice, it would appear to depend on the
attic venting and how well the attic is insulated. We have a fan in a
bathroom used for showers that vents into the attic and have had no
problems. House is now 40 years old. As usual YMMV.

LB

Of course, you neglected to mention where you live. That makes a difference.

Doug Kanter wrote:

wrote in message ...
Tom Edelbrok wrote:

I have an older home that I want to install a bathroom fan into. Is it ok
for the exhaust air to duct into the attic, or must it be ducted to to
the
outside of the house through the wall. If it can just be ducted into the
attic it will save a lot of effort.I can't imagine a small amount of
moisture messing up the attic.

Tom

First of all is this bathroom used for showers?
If not, you can definitely vent in the attic.
If so, in spite of all oter advice, it would appear to depend on the
attic venting and how well the attic is insulated. We have a fan in a
bathroom used for showers that vents into the attic and have had no
problems. House is now 40 years old. As usual YMMV.

LB

Of course, you neglected to mention where you live. That makes a difference.

Northern NJ - Just south of Rt 80 Its about 34 right now.

LB

wrote in message ...
Doug Kanter wrote:

wrote in message ...
Tom Edelbrok wrote:

I have an older home that I want to install a bathroom fan into. Is it
ok
for the exhaust air to duct into the attic, or must it be ducted to to
the
outside of the house through the wall. If it can just be ducted into
the
attic it will save a lot of effort.I can't imagine a small amount of
moisture messing up the attic.

Tom

First of all is this bathroom used for showers?
If not, you can definitely vent in the attic.
If so, in spite of all oter advice, it would appear to depend on the
attic venting and how well the attic is insulated. We have a fan in a
bathroom used for showers that vents into the attic and have had no
problems. House is now 40 years old. As usual YMMV.

LB

Of course, you neglected to mention where you live. That makes a
difference.

Northern NJ - Just south of Rt 80 Its about 34 right now.

LB

Either your attic is extremely well ventilated, or the steam hasn't caught
up with you yet.

Doug Kanter wrote:

wrote in message ...
Doug Kanter wrote:

wrote in message ...
Tom Edelbrok wrote:

I have an older home that I want to install a bathroom fan into. Is it
ok
for the exhaust air to duct into the attic, or must it be ducted to to
the
outside of the house through the wall. If it can just be ducted into
the
attic it will save a lot of effort.I can't imagine a small amount of
moisture messing up the attic.

Tom

First of all is this bathroom used for showers?
If not, you can definitely vent in the attic.
If so, in spite of all oter advice, it would appear to depend on the
attic venting and how well the attic is insulated. We have a fan in a
bathroom used for showers that vents into the attic and have had no
problems. House is now 40 years old. As usual YMMV.

LB

Of course, you neglected to mention where you live. That makes a
difference.

Northern NJ - Just south of Rt 80 Its about 34 right now.

LB

Either your attic is extremely well ventilated, or the steam hasn't caught
up with you yet.

The venting is an eve vent at either end of this very simple attic -
just a 50 X 26 rectangle. There are just two of us in the house so
maybe low use is a factor.

LB

I have an older home (1920) with 2 bathrooms missing fans. What I did
was to get the fan/light combo and cut out the ceiling from the fan to
the wall. I then cut through the outside wall, just above the ceiling
to install a vent. Connected the vent to the fan with a flexible metal
snake tube (think dryer vent). After, patched up the hole in the
ceiling and put a coat of textured ceiling paint over it (hides the
ametuer job of patching). Connected the fan/light to same switch, so
both fan and light come on when switch is turned.

Keeps the bathroom much dryer after showering. Took abolut 2 days to do
each bathroom, between the installation and painting.

It's more energy-efficient to finish the shower, then turn on
the fan switch, and let a humidistat turn off the fan.


Probably, but at that point, your walls are soaked. Not good for wallpaper
(if any), no matter WHAT the manufacturer claims about it being made for
moist environments.

Personally, since my toilet is in a separate enclosure than the shower,
I blast the shower air into the rest of the house, which
desparately needs the humidity anyway. During the summer, I have to
stop doing that.

Jeff Wisnia wrote:

Me too. We have two second floor bathrooms with tub/showers whose vent
fans just dump into the attic. I was concerned too, but took our
builder's word that there was adequate attic venting to handle it.

Location is near Boston and the attic is vented by grills all along the
undersides of the front and rear eaves and a ridge vent along the whole
length of the roof.

I had about 25% of the attic "floor space" covered with plywood and put
plenty of lighting up there too. We store a lot of inherited "chatckas"
we can't bear to throw out up there, and go up at least ten times a year
to hunt for stuff or to change filters in the HVAC air handler.

In the 19 years since we had the place built I haven't noticed anything
wrong in the attic.

Today's Massachusetts building code requires that bathrooms have exhaust fans
which vent directly to the outside. Venting to the attic is no longer
acceptable Building Code 1205.2.1 .