Bathroom exhaust fan

wndnns · 05-02-2012, 12:10 AM

I am installing a bathroom fan in my main floor bathroom. I am forced to wall mount it because i don't want to go up in the attic. I am running the duct down the wall to the basement. Then through the outside wall. I was hoping to use 4" duct but this is not possible due to my 2 x 4 walls. I will use 3". My question: is there any benefit to running the 3" down the wall & then connecting the duct to a 4" in the basement to the outside. Can anyone recommend a good 3" fan?
Thanks

carmon · 05-02-2012, 12:12 AM

wow the caps are killing me..................

carmon · 05-02-2012, 12:14 AM

go in the attic and do it right .....why add all that pipe for nothing....... sometimes doing it right is not the easiest way.......

wndnns · 05-02-2012, 12:20 AM

I normally would not have a problem going up in the attic but when I open my attic door the insulation is everywhere. You cannot see a thing for blown in insulation. If I could work up in the attic where would you choose to vent it? Believe me going down to the basement was no easy chore either.

wndnns · 05-02-2012, 12:36 AM

Also my roof is 4 sided so I can't add a vent to the outside wall in the attic. I have heard mention of venting to the soffits. I can't even see mine with all the insulation. I really don't want to be cutting a hole in the roof at this time. Is it really that bad going down 6 feet into the basement then 6 feet to outside? Only the one 90 turn. It has to be better than the no fan which has been like that for 50+ years??

**beenthere** · 05-02-2012, 05:36 AM

Quote:

Originally Posted by carmon

wow the caps are killing me..................

Its fixed.

wndnns · 05-02-2012, 07:51 AM

Can anybody tell me if there is any benefit going from my 3" duct to 4" duct outside. If there is no benefit then I will use all 3".
Thanks

hammerlane · 05-02-2012, 08:04 AM

Quote:

Originally Posted by wndnns

Can anybody tell me if there is any benefit going from my 3" duct to 4" duct outside. If there is no benefit then I will use all 3".
Thanks

I do not know how much more airflow thru the 3" vertical section you will have because of the 4" horizontal in the basement but I do not think it would hurt.

What at size does the fan call for?

As a side not I'd be concerned about:

Quote:

Originally Posted by wndnns

I have heard mention of venting to the soffits. I can't even see mine with all the insulation.

Can you see light from the soffit venting in the attic. If you do not see light, then most likely the vents are covered by an improper blown in insulation job.

wndnns · 05-02-2012, 08:17 AM

The bathroom is 5' x 8'. I was thinking a 70 cfm. Any thoughts on size?The 3" duct has disappointed me because on the one wall it was wide enough for a 4" duct but when I tried installing the 4" it would not work because of water pipes & venting in this wall. I am not sure why the one wall is 2 x 6 and the rest 2x4 but it is. Good point on the soffits. I may have to have a look up there again. Ugh.. Is there a soffit style vent?

kenatofc · 05-02-2012, 08:27 AM

If this is an exterior bath room, why not vent through the wall to the outside ??

Ken in WV

wndnns · 05-02-2012, 09:22 AM

It is an exterior bathroom. The issue I had is on the exterior wall there is a window (I guess that is where my ventilation is suppose to be but its a pain to open & never happens) Also If I installed on the exterior wall I would still need to run the electrical to the switch which would be a problem. Thanks for the reply.

sqslist · 05-02-2012, 03:14 PM

Quote:

Originally Posted by wndnns

I would still need to run the electrical to the switch which would be a problem.

No you dont. There are modls on a market with all sorts of built in switches: infrared, light sensors, motion sensors, humidity sensors and even programmable combinations. So you just need a power provided to the installation spot, which is easier to implement.

M3 Pete · 05-02-2012, 10:12 PM

Quote:

Originally Posted by sqslist

No you dont. There are modls on a market with all sorts of built in switches: infrared, light sensors, motion sensors, humidity sensors and even programmable combinations. So you just need a power provided to the installation spot, which is easier to implement.

I'm no electrician, but I think you have to wire a fan to a switch, even if it has a humidity sensor.

I'd welcome input from the electricians here.

kenatofc · 05-02-2012, 10:51 PM

Well, here I go again butting in. Your measurements lead me to believe that your window is over the toilet and the tub is next to the toilet with the sink near the door... Does not really make any difference but if there is sufficient space over the window, I would mount the fan there and run the electrical off of the ceiling light (if my assumptions are correct) directly. Then the fan would come on when the bath light goes on and all you wound have to repair would be the channel you would have to cut into the sheet rock or plaster for the electrical connection. If the only light for the room is over the sink, I would still rather cut into the rock or plaster and run the electrical rather than try to run the exhaust down and then out. Don't install a fan ? heater as that will certainly be too many amps. An exhaust fan should be no problem. My 3 cents !!

Ken in WV

how · 05-02-2012, 11:14 PM

Dropping from a vertical 3" into a vertical 4" is going to be a dumping area for lint in the 4" pipe with the reduced air flow. If you are commited to going the basement route, is there a way to oval a 4" to fit where you were going to use the 3".

05-02-2012, 12:10 AM	#1
wndnns Newbie Join Date: Apr 2012 Posts: 15	Bathroom exhaust fan I am installing a bathroom fan in my main floor bathroom. I am forced to wall mount it because i don't want to go up in the attic. I am running the duct down the wall to the basement. Then through the outside wall. I was hoping to use 4" duct but this is not possible due to my 2 x 4 walls. I will use 3". My question: is there any benefit to running the 3" down the wall & then connecting the duct to a 4" in the basement to the outside. Can anyone recommend a good 3" fan? Thanks Last edited by beenthere; 05-02-2012 at 05:35 AM. Reason: Fixed all caps

05-02-2012, 12:12 AM	#2
carmon Member Join Date: May 2010 Location: winnipeg manitoba canada Posts: 712	Bathroom exhaust fan wow the caps are killing me..................

05-02-2012, 12:14 AM	#3
carmon Member Join Date: May 2010 Location: winnipeg manitoba canada Posts: 712	Bathroom exhaust fan go in the attic and do it right .....why add all that pipe for nothing....... sometimes doing it right is not the easiest way.......

05-02-2012, 12:20 AM	#4
wndnns Newbie Join Date: Apr 2012 Posts: 15	Bathroom exhaust fan I normally would not have a problem going up in the attic but when I open my attic door the insulation is everywhere. You cannot see a thing for blown in insulation. If I could work up in the attic where would you choose to vent it? Believe me going down to the basement was no easy chore either.

05-02-2012, 12:36 AM	#5
wndnns Newbie Join Date: Apr 2012 Posts: 15	Bathroom exhaust fan Also my roof is 4 sided so I can't add a vent to the outside wall in the attic. I have heard mention of venting to the soffits. I can't even see mine with all the insulation. I really don't want to be cutting a hole in the roof at this time. Is it really that bad going down 6 feet into the basement then 6 feet to outside? Only the one 90 turn. It has to be better than the no fan which has been like that for 50+ years?? Last edited by wndnns; 05-02-2012 at 12:46 AM.

Bathroom exhaust fan