View Full Version : Venting a bathroom...
I have an older home (1940's) that has a bathroom without a powered fan. We've been getting by with opening the window in the shower to vent it, but I redid the shower and put in a glass block window with a much smaller window and really need something now.
First option I looked at was putting in a ceiling fan. But that entails cutting into the ceiling, mounting the unit in the joists, running the electrical up there, ducting 10 feet across, up into a crawl space (one story house, finished attic) and going out the wall. I don't have enough space in the soffit/fascia for a vent, so I'd have to go over ten feet, 90 up into the crawl space and then 90 again and out the wall. Plus the crawlspace is unheated, so I'd also run the risk of condensation in the ceiling.
What struck me as an easier, quieter and more efficient option was to use an inline fan. Put a 6x10 register near the top of my bathroom wall, drop 4in insulated flexible duct down into the basement, one 90 turn down the joist, into the the inline fan and then out the side of the house.
The basement joists are exposed and much easier to hang duct and fan than the ceiling. The flex duct can be fished down the wall. Electrical would be much easier...
So, a couple few questions...
From what I've been to glean online, it appears it's perfectly fine to put a fan in the basement and draw air downwards and out, in fact, Fantech shows this in one of their brochures. Is this correct?
Fan choices in my price range are the Nutone ILF120, Fantech FR100 and Fantech FG4. All move about the same amount of air. Bathroom is about 6x10, it appears they will all deliver enough CFM. I'm leaning towards the Fantech FG4, seems to be the better choice.
With the fan on in the winter, will I basically be blowing all my paid-for hot air right outside? Bathroom gets plenty of warm air blown into it...
Thanks in advance, Jim.
the dangling wrangler
10-06-2008, 05:02 PM
Don't know if you could use it but, there's a company that makes a recirculating type fan. No duct at all.
Don't know if you could use it but, there's a company that makes a recirculating type fan. No duct at all.
For a bathroom? Wouldn't that just move the moist air to another part of the house?
the dangling wrangler
10-06-2008, 05:27 PM
For a bathroom? Wouldn't that just move the moist air to another part of the house?
Yes, for a bathroom. I wouldn't use it but, there must be a need, or they wouldn't make them. From reading your post, I think you have a handle on this.
Ha, I just realized I said ceiling fan... I mean one of the exhaust fans you mount into the ceiling, a regular bathroom fan.
the dangling wrangler
10-06-2008, 05:31 PM
Ha, I just realized I said ceiling fan... I mean one of the exhaust fans you mount into the ceiling, a regular bathroom fan.
I understood what you meant.No big deal.
Yes, for a bathroom. I wouldn't use it but, there must be a need, or they wouldn't make them. From reading your post, I think you have a handle on this.
Thanks, what I've read seems accurate, but I thought I'd stop here and seek the opinions of some experienced people first.
hivacer
10-06-2008, 05:34 PM
The inline fan should be fine and fantech makes a fine product. I dont see any problem with doing it the way you propose. That 4" flex likes to kink so you will need room for wide turns with it or use hard elbows. This will also be a very quiet system. You could also have it installed on a humidistat to remove humidity from the bathroom if you want to get real fancy.
the dangling wrangler
10-06-2008, 05:36 PM
Thanks, what I've read seems accurate, but I thought I'd stop here and seek the opinions of some experienced people first.
We're limited to the information we can dispense here. So, if I'm beating around the bush, that's the reason.
The inline fan should be fine and fantech makes a fine product. I dont see any problem with doing it the way you propose. That 4" flex likes to kink so you will need room for wide turns with it or use hard elbows. This will also be a very quiet system. You could also have it installed on a humidistat to remove humidity from the bathroom if you want to get real fancy.
Yes, I was going to use a hard elbow, kind of a tight turn at one point, figured the flex duct would want to fold itself closed.
As far as fancy, I was going to use a timer switch of some sort. We'll need this for fart gases also. :)
We're limited to the information we can dispense here. So, if I'm beating around the bush, that's the reason.
Understood, thank you.
the dangling wrangler
10-06-2008, 06:01 PM
Understood, thank you.
You're Welcome.
pecmsg
10-06-2008, 06:30 PM
This is what you want
http://www.fantech.net/
This is what you want
http://www.fantech.net/
Yup, been all over that site, thanks.
Going to pick up the FG4.
Shophound
10-07-2008, 11:29 AM
If you're concerned about sucking heated air out of the bath, that is going to happen any time you run the fan. Unless a window to the outdoors is open, the make-up air will come from the house, and any leaks in the house envelope will also pull in air from outside, which in turn must be heated or cooled, depending on the season.
So...to minimize the exhaust fan's effect on your indoor environment, run it with discretion. Run it during showering and for odor removal; the timer is a good idea.
The strategy you outline, without actually seeing your place, sounds doable.
Excellent, thanks.
I'm a little concerned this fan will be too powerful for the small bathroom. According to the calculations I can find, I'll need about 60CFM to vent it properly. The FG4 will pull 135CFM max.
Not really knowing how to calculate this, I've come up with an Equivalent Duct Length of about 85ft. 25ft 4in insulated flex duct + 90 elbow + wall cap. But I have no idea how work that back to Static Pressure (inches WG) to figure the CFM for the FG4.
If I need to throttle then fan back, which is better? Speed controller or some sort of iris/baffle?
DanW13
10-07-2008, 11:53 PM
Why not have a HRV/ERV installed with exhaust for your bathrooms, kitchen and other rooms to remove the stale air from the home and will also bring in fresh air or make-up air back into the home to give you the proper amount of air changes needed for your home to give you better indoor air quaility.
ronnrs
10-08-2008, 01:30 AM
Home depot sells a timer that looks like a light switch and can be set to four different time durations.
fat bob
10-08-2008, 10:45 AM
You might also consider a mini-dehumidifier. I got one for my master. I also have an exhaust fan, but the mini-dehumidifier is nice especially in winter, since it generates some heat, uses only 60 watts, and does remove some humidity.
amigadude
10-14-2008, 05:36 PM
I did the attic route some years back, but I did the PG100 style unit which sounds ideal for your situation as well. Mine has been running the attic for 7-8 years, at least, without any trouble whatsover. So, I'll second the call for Fantech!
I'm a little confused as to why you want the FG4 since it sounds like it is better suited for HVAC vents than ventilation. Might be me though...
Also, around here we don't use the vent in the winter, except for those aforementioned gases, since the humidity is already low.
From what I've been able to garner... going with the FG4 because the cost difference between that and the FR100 is minimal. The FG4 appears to be a little more heavy duty and offers a few more CFMs.
Problem I'm having now is finding a stack head/register box (not sure of the proper term), 10 x 6 x 3 1/4 with a connector at the bottom I can use to put the 4in flex duct down the stud wall.
Fantech has this unit:
http://www.fantech.net/accessories3_12.jpg
http://www.fantech.net/accessories3.htm#11
That would fit their round grilles, but the Significant Other says she doesn't want the round grille... Plus there's a 10x6 register down the wall from where I wanted to put this, we were going to find some nice register grilles to match.
DanW13
10-14-2008, 08:14 PM
If you haven't made you purchase for the ventilation fans yet you may want to check out this site which I happened to come across last nigth while doing some searching for fans myself for the bathrooms, there mixvent centrifugal fans similar to what fantech sells but there smaller fans and have the ability to connect more than one motor inline with other motors should the need ever arise. Another feature of these fans is when you need to pull the motor there's no need to disconect the duct work to pull the motor as the motor is connected separtely from the duct work. Here's a link for the fans motors
http://www.hvacquick.com/catalog_files/solerpalau_TD_Extended_Catalog.pdf
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