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Exhaust fan upgrade

PoppyNovice | Posted in General Discussion on July 17, 2009 06:17am

Good morning,

I am about to undertake a project that I need some experienced help with.

Our master bath is 5’ wide 4’ in length and about 20’ or so high (all the way to the roof…with a skylight).  We are about to remodel and I would like to improve the ventilation.  There are some mold issues around the register overhang I would like to eliminate…the chief cause being condensation during the high humidity seasons; oddly enough it’s not in the higher levels of the ceiling?

The current layout is typical: through the door the toilet is to the left with the shower stall running parallel. The current fan is about 8’ over the toilet (standard wall mounted fart fan), opposite the toilet  is the register ducting, a little over 8’ from the floor, runs the width of the room, and overhangs about 18’’; otherwise the walls are unobstructed floor to roof.

I have a few questions:

1)      Is this worth doing?

2)      What size fan?

3)    Do I need to add ducting over the shower? If so how?

3)      Are there any codes I need to follow?

I have a few ideas but welcome all suggestions, comments & ideas….after all I’m just an ambitious armature who knows just enough to be dangerous.

Thanks

Shawn

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Replies

  1. billzbz | Jul 17, 2009 06:20pm | #1

    Take a look at Fantech remote exhast fans.  I have them in 4 bathrooms and never have consensation or mildew anymore.  I put in two exhast ports per bathroom, one over the bath/shower and one over the sink.   Vent the exhaust air to the outside. 

    1. PoppyNovice | Jul 21, 2009 08:37am | #3

      Thanks for the suggestions billzbz. I’ve downloaded the PDF’s from Fantech trying to decide which one I can make work.

      I’m really bad at follow-up but I’ll try to remember to let you know how it worked out.

      <!----><!----> <!---->

      Thanks again

      Shawn

      1. Pelipeth | Jul 22, 2009 02:51am | #6

        Be aware that to put one Fantech on you put ALL the exhaust fans on. Can
        suck alot of conditioned air OUT of your home. I'm a big fan of Panasonic (no pun intended). Great product, super quiet.

        1. User avater
          Jeff_Clarke | Jul 22, 2009 06:22am | #7

          You can adapt to that by including a 24 VAC operated Honeywell damper in line above the ceiling grille, wired to the switch in each 'exhaustable' location - at a cost of maybe $150/per location (damper + transformer) of course.   Then again, there's only the cost of one fan.

          Jeff

  2. DanH | Jul 17, 2009 06:25pm | #2

    The standard code-minimum bath fan is 50 CFM, which is barely adequate for a normal sized bath -- 70-80 CFM is the more realistic minimum. You don't need a fan sized exactly in proportion to bath size, but you do need to increase size as the bath gets larger, maybe in proportion to the square root. My thumb suck would be that 100 CFM would be the minimum you should have.

    As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
    1. PoppyNovice | Jul 21, 2009 08:40am | #4

      Thanks for the suggestions DanH. I’ve downloaded the PDF’s from Fantech trying to decide which one I can make work. I agree about the bigger size…I would like to use the PB370 but I’m concerned about the noise….maybe a happy medium like the 190?

      I’m really bad at follow-up but I’ll try to remember to let you know how it worked out.

      <!----><!----> <!---->

      Thanks again

      Shawn

      BTW I really like the quote…

      Edited 7/23/2009 11:44 am ET by PoppyNovice

  3. User avater
    Jeff_Clarke | Jul 21, 2009 02:17pm | #5

    Make sure the bathroom door is undercut for ventilation.

    Add a NuTone QT200 (200 cfm) fan or even QT300 - you can do this 'remote mount' if you want.

    I've done a remote fan tied to a linear grille above the shower glass enclosure line - expensive but it worked.

    Paint with 'bathroom paint' - mildew resistant.

    Jeff

  4. wookie | Jul 22, 2009 06:31am | #8

    I second the Panasonic suggested. Excellent product, VERY quiet.

    wookie

    1. PoppyNovice | Jul 23, 2009 06:49pm | #9

      I’ve removed the old fan…the joints were duct taped…good grief! Anyway the existing ducting is 3’’ and I’m planning to replace it with flex ducting, I’m pretty sure I can go from 4’’-3’’ but not 6’’-3’’ without replacing the roof vent (that’s not an option…3 stories) correct?

      I’ve looked at both the Fantech & the Panasonic…I’ve always been satisfied with any Pansonic product I have, but I like the Fantech’s ‘ceiling grill housing’…I’ve never had one apart, do the non-housing grills mount into the surface and join to the ducting? Is the convenience of the ‘housing’ worth the extra cost? Panasonic wants $200+ for 2 grills…that seems a bit steep?

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