Replies

1. 
   calvin | Jan 15, 2015 06:37pm | #1

   Easy answer her

   Find an excellent remodeling contractor that has done numerous bath reno's correctly.

   I would recommend changing to a remote exhaust unit from Fantech or Panasonic.  Join the two ductworks for one exit through the roof.  More than likely 6" exhaust from fan out.  You can combo 2 - 4" from each bath.  You will have the option to make the exhaust heads both a sealed (or not) lamp as well as exhaust.

   I use well supported insulated flex duct wherever possible.  You'll find the flex offered by and recommend use by both manufacturers, but I've purchased the same rated goods from elsewhere a bit cheaper.  I bought in bulk, holding for the next job.

   Switching.  You can make up both baths to fan with 2 wire w/grnd.  The fan will draw air from both baths whenever either is turned on, unless you install powered dampers which I have never had done.  The power feed is to the fan box, with switch legs dropped to each bath.

   Use timers in each bath.  Too often the old bath fans turned off way to soon and often water was left  collecting in the pipe.

   so, this method of a remote fan may be more wiring invasive and drywall patching than you want to do.  If so, look to each manufacturer for their self contained bath fans.  They will have everything from motion detectors to delayed shutoff settings you can program to your liking.  I think both have the can like look within the housing if you are interested in that change.

1. 
   jimmiem | Jan 15, 2015 07:32pm | #2

   Calvin

   First problem....finding an excellent remodeling contractor.  When you said 6" and 2-4"  did you mean feet or inches?  The front bath has probably an uphill run of 10+ feet to get to the center of the house then another couple of feet to the roof vent. I'll check to see if these fans can handle that.  I don't mind the drywall work or the electrical work if I can do it myself.  My big concern is finding a contractor who will get it right.....are you available?    

1. 
   calvin | Jan 15, 2015 10:08pm | #5

   Jim

   6 inch pipe from remote fan to roof jack.  One 4inch from each bath to remote fan.

   the distances from baths to the roof jack you list is not too much for a decent remote fan.  You can and should install a 6 inch backdraft preventer after the remote fan.  I've siliconed a heavy fender washer to the flapper of the roof jack.  Keeps the flap shut till it's opened by the exhaust.

   too far back to Boston, and I hate bath remodels.  They're always on the second floor, usually are small, and cost the most a sq. ft.........the ho mowers look at you like a bandit.  But thanks.

1. 
   jimmiem | Jan 16, 2015 05:58am | #6

   Remote Fan

   Are both bathrooms ducted to one remote fan located in the attic?

1. 
   calvin | Jan 16, 2015 06:38am | #7

   Jim

   Yes

   http://www.hvacquick.com/howtos/howto_multiple.php

   fantech

   http://www.fantech.net/enus/Product_range/

   http://www.fantech.net/Documents/Leaflets/412220%20Ventilation%20Solutions%20-%20Bathrooms.pdf

   Panasonic

   http://m.shop.panasonic.com/shop/ac-vent-fans-and-tools-ventilation-systems?selectedTopNavId=nav8

   or you can use two fans and connect in attic for one exit through roof.  I'd isolate each bath with a backdraft damper b/4 the "y".

2. 
   jimmiem | Jan 16, 2015 08:37am | #8

   Calvin

   Thank You.

   Do you have a favorite brand/model that you would recommend?

3. 
   calvin | Jan 16, 2015 09:37am | #9

   Jim

   I have used both Fantech and Panasonic exclusively for quite some time.  I am satisfied with both companies and have had good contact with Fantech when needing an answer.  Don't think I've reached out to Panasonic much.

   the folks at hvacquik are good contacts as well.  I do make most purchases locally but sometimes the availability here is limited.

   Once you get your square footage and placement, type of outlets and lengths of pipe figured, that should place you in range of some of the applicable models if you go remote.

   for separate in ceiling/wall units there should be enough options of either brand.  Panasonic I used in the last remodel had built in motion sensors, continuous low speed ventilation, as well as time delay shut offs.  Spec'd and provided by the customer (the owner of my plumbing supply) so he did the research.  They fit his plan for the master and guest baths.

   getting the old out sometimes involves cutting mounting bars from below if there's access issues.  I've used a handle meant for holding sawzall blades.  Less jiggle and damage than a sawzall approach .  You might find adding wire is in your future, to split fan/light/heat options.

4. 
   jimmiem | Jan 20, 2015 07:46pm | #12

   Calvin

   I called HVACQUICK today.  I told the tech what I need to do and he said just provide the sq ft of the two bathrooms and maybe the run lengths and they could provide everything I need....one stop shopping.  Thanks again for pointing me in the right direction.

5. 
   calvin | Jan 20, 2015 10:41pm | #13

   You're welcome

   And best of luck in the install.

   up in the attic or on the roof, remember.  Never back up.

2. 
   jimmiem | Jan 15, 2015 08:09pm | #3

   Funny You Should Say That

   We bought the house new.  Guess who installed the exhaust in the first bathroom  (the second bathroom exhaust was done a few years later)?  You guessed it....the GC had the electrician install it and all he did was lay the duct on the insulation in the attic.  I said not a good idea.....he said that's the way he does it.   I brought in an HVAC guy to duct it through the roof.

3. 
   jimmiem | Jan 15, 2015 09:33pm | #4

   Lucky I found it but my luck eventually ran out as the condensation ran in.

4. 
   renosteinke | Jan 20, 2015 02:09pm | #10

   So Easy & So Hard

   Bath fans are typically installed in new construction by the HVAC guy (less often the plumber), with the electrician installing the switch & wiring. BUT- that's new work.

   That's where your troubles begin. The parts house has pallets of minimalist bath fans they literally give away when the HVAC guy comes in for the the other stuff on the job. That's the fan you probbly have installed right now.

   The cheap fans are adequate only if the bath is very small, and the exhaust path is both short and straight. That 'foil flex' ducting uses has the air resistance of a cork in the line. All such fans ever do is make noise.

   A good fan will set you back a C-note. Houses rarely have space for someone to access the ductwork, and opening sizes vary, so you'll need someone competent to fix the ceiling when the new fan is in. Ditto for the outside- placement of the vent matters, and flashing can be critical. The installer will also need to add blocking to support the fan.  

   Timers,  lights, night lights, heaters are all nice ... but your existing wiring probablywon't accomodate it all. Again, someone needs to fix the wall and ceiling after the new wires are run.

   The best fan won't work unless fresh air can enter the room. You want plenty of clearance - one or two inches - under the bathroom door for this reason.Or, have a vent louver in the door.

   On a personal note, I am fond of Sola-Tube, a line of tubular sky lights. They have models with integral exhaust fans and lights. Google them. For 'simple' exhaust fans, Panasonic rules.

1. 
   DanH | Jan 20, 2015 07:09pm | #11

   I did manage to replace the builder-grade 50cfm fan in our downstairs bath with a much better 80cfm unit,using orthosopic surgery (and hence no ceiling repair), but the existing ductwork was at least short and direct (if a hair undersized for the new fan).  And you probably couldn't pay someone to use the techniques I used to do the install (taking easily 3 times as long as it would if I'd chopped the ceiling).

5. 
   IdahoDon | Jan 25, 2015 10:42am | #14

   there's nothing wrong with metal duct if it's insulated, but if not the moisture condenses rapidly and drips into places it shouldn't.  Flex duct cuts way down on noise, is inexpensive to install and overall it's hard to beat.  Fantec is my go-to fan since they are relatively inexpensive when bought on sale (less than $150), easy to install, and so quiet the only noise you'll hear are the draft flaps opening up when it's turned on.

6. 
   renosteinke | Jan 25, 2015 12:34pm | #15

   Flex Duct is for Losers

   You read it right ... I stridently oppose the use of the most common material foundon bath fans.

   Let's be clear: I am referring to that foil-accordion stuff .

   What's lost? First off, air flow. The CFM figures advertised for fans are based upon smooth, rigid, straight duct over a short length, with a single formed 90. Vary from that at all, and you lose air flow.

   FlexDuct loses air flow first when the air contacts its' very rough corrugated inside. As the duct is stretched, you lose diameter. Air pressure is lost flexing the thin duct material, meaning more flow lost. Bends are extremely likely to cause constrictions, often because the stuff is forced to make tighter turns than are proper.  The material is subject to crushing, and easily damaged.

   Insulated? I've never seen an  bath fan exhaust duct that was insulated. Yes, condensation is a concern. With rigid duct, you can pitch it towards the outlet. Flex will simply trap the water, catch any lint / or dust in the fan flow, and make a very nice fungus farm in the duct.

   Note that, since the fans are rated using unrealistic assumptions for the duct, you will NEED a larger than minimum-size fan to accomplish anything.

1. 
   calvin | Jan 25, 2015 01:52pm | #16

   'Reno

   have you used the insulated flex recommended and supplied for bathroom exhaust venting?

   do you never vent out the roof?

   thanks