Help With Bathroom Fans

[Dan Mages]

One of the many projects on my honey-do list for this winter is a ceiling fan for the guest bath where we currently do not have one. One thing I really hate is a loud fan running in the bathroom, so I did some research and found some good looking models from Panasonic that run at 20-40 db. The model I am looking at is FV-08VKSL1 http://www2.panasonic.com/consumer-electronics/shop/Building-Products/Ventilation-Systems/Ceiling-Insert-Fans/model.FV-08VKSL1_11002_7000000000000005702.

Last time I bought one I just blindly picked one out at Home Depot and popped it in the ceiling. This time I want to be smarter about it. A few questions:

1. How do I determine how many CFMs I would need? I roughly calculate the bathroom at 350-400 cubic ft (5x10x7.5).
2. These fans have DC motors that can be programmed to run constantly at low CFMs when the switch is "off". Is this wise? How will this effect the motor life?
3. Are there other similar brands I should check out?
4. Does anyone make a multiroom bathroom fan? The hall bath and master bath are practically next to each other. Only having one fan in the attic and one whole in the roof to maintain is rather appealing!

Thanks for the advice.

Dan

[Matt Ocel]

Dan
What are you trying to accomplish with the fan, exhaust odors or exchange air?

[Jim Becker]

If you can do it, a remote fan setup is going to be much quieter than a ceiling unit with an integral fan. We have that for both our new master bath (two inlets, both lighted) and for our new guest bath. For the former, the fan is actually up in the attic and for the latter, the fan is in the crawl space. They provide excellent ventilation with minimal noise. You do know they are on, but you don't have to kick up the radio volume, etc. When I replace the fan/fixture in the girls' bathroom, it will be similar. Our units are from Fantec.

[Tom Godley]

I have used the Panasonic units -- the quiet ones are very quiet.

The last couple of bathrooms that I have totally remodeled I have installed units from Fantec. They are an inline rotary fan and are extremely quiet - this type is often used in radon exhaust systems. The fans are normally installed in the attic -- they also make a exterior wall mount unit that I have used. I also like the vents that they sell - they are round plastic - I use them for the exhaust air as well as for the HVAC air - this makes for a very uniform look. I have used the larger units in other rooms for HVAC

Unless I was installing some type of air change system for a very tight house that also included a heat transfer module - I would stay away from multi room exhaust units.

I like to make bathrooms where you have a toilet and/or shower behind a separate door within a bath. The Fantec units are ideal for this. I place one vent inside the shower area and another over the toilet area and connect them to one fan unit that is controlled by a wall timer. The plastic vents can be installed directly in the shower area. This allows you to install a powerful fan that will do the job as well be silent.

[Bob Rufener]

Check this website. It should provide you with lots of information that will help you.

http://www.broan.com/display/router.asp?CategoryID=100353

[Ben Franz]

I've used multi-room exhaust fans made by Aldes (or American Aldes) several times. I'm not sure about the name as it's been a few years but they advertise in Fine Homebuilding and, of course, Google can find them. They sell through HVAC distributors but also direct if no local distr. They have systems that serve only 2 outlets up to 6 (I think). The fan is mounted in the attic and insulated flex duct runs to the ceiling outlets. They are so quiet you have to look at the ceiling damper to know if the fan is on. Cost wise, it isn't much more expensive than buying multiple high quality ceiling mounted fans. You run multiple switch legs in parallel from each place you want to control the fan.

I tried using a special fan switch once (also in trade mags) that was a 2 ple switch where the 1st (normal) pole was for the light and the 2nd pole was an adjustable time delay off for the fan so that it would run for a set period after the light was turned off. There were a few problems: it was expensive ($40??), it only came in white as a normal paddle switch (no Decora), it couldn't be used in a parallel setup from multiple control points (without some kind of electrical or electronic kludge). I still have 2 of these switches in my electrical boneyard box.

Fan sizing usually is based on 10 air changes per hour so a 400 cu. ft. room would need 400x10/60 or 66 cfm fan.

Hope this hellps.

[Lee Schierer]

Figure out the total volume of the room and size the fan to change the air in about 10 minutes. However, bear in mind that in the winter months or anytime with all the windows closed you may get far less perfomance from the fan as air has to get into the room in order for the fan to blow it outside. If your house is otherwise tight, it may not move much air. Also running the fan all the time will not use much power since it is DC, but it could pull lots of heated (or cooled) air outside. I think the code says they should run when the lights are on in the room. Note that fans can also cause back drafts on gas furnaces, fireplaces, dryers and hotwater heaters. If you have a radon system you can also affect the performanc of that system by installing a fan.

[David G Baker]

As has been written "remote fan" is the way to go if you want quiet. They are as functional as ceiling mounted fans or in some cases better because a larger more powerful fan can be used due to the distance from the room that is being vented.

[Matt Ocel]

Do not just add a fan!!!!!!
There are many factors that need to be considered.
Some, if not calculated properly can be deadly!

[Dan Mages]

Do not just add a fan!!!!!!
There are many factors that need to be considered.
Some, if not calculated properly can be deadly!

OKAY!!! Please elaborate and not just yell fire in the crowded theater.

Dan

[Jim Mattheiss]

I put a Panasonic in the powder room. It's really quiet - it get's left on often as it's that quiet.

What I am going to do is when the Broan Fan in the master bath dies, I'm going to remove the fan guts (2 screws hold the motor / squirrel cage assembly) and use a Fantech inline fan upstream.

I forgot to circle back at the flea market and buy the Fanteck FR100 for $20 (NIB). Now I have to pay retail...

Matt's probably yelling about the possibility of drawing fumes back down the chimney if you run a large fan in a tight house.

Jim

[Dan Mages]

Dan
What are you trying to accomplish with the fan, exhaust odors or exchange air?

Exaust Odors and more importantly moisture.

Thanks for the lead on Fantech. Their remote mounted models will work perfectly!!

Dan

[Matt Ocel]

OKAY!!! Please elaborate and not just yell fire in the crowded theater.

Dan

Sorry for not getting back sooner. Went out for dinner.

Simply put, Whatever air you exhaust out of your house, you need to supply back into your house.

You need to make sure you have adequate make up air. If you have an atmospherically vented furnace and/or water heater and you add a continously running bath fan you can create a back draft, as Jim said.

You really need to have a qualified HVAC contractor run CFM calculations before installing any exhaust fans.

I don't want to scream fire in a crouded theatre, I just want to say in a low voice that there is a possibility of smoke in the air.

I will not reside a house and install "house wrap - Tyvek" on a home with an atmospherically vented furnace/waterheater without proper make up air.
House wrap alone on an old house has been the cause of co2 poisoning.

Please be careful!!!

[Derek Stevens]

Do not just add a fan!!!!!!
There are many factors that need to be considered.
Some, if not calculated properly can be deadly!
hmmm, I have been a historic preservation builder and woodworker for the last 30 yrs, and though many older homes haven't any fan, I haven't run into deadly fan syndrome yet... though after a day of coffee, hot pockets and and an overlarge burrito, there are times that without a fan, death would be welcome...

[Matt Ocel]

hmmm, I have been a historic preservation builder and woodworker for the last 30 yrs, and though many older homes haven't any fan, I haven't run into deadly fan syndrome yet... though after a day of coffee, hot pockets and and an overlarge burrito, there are times that without a fan, death would be welcome...

Although my years of experience don't add up to thirty years, I can speak with over twenty, and what I am saying is you have to be careful.
When you start messing around with a homes ventilation system you have to know what you are doing.
Sure adding one bath fan might not cause a problem, but what if, there has been other past exhaust fans added in other baths of high CFM, or what if there is a high CFM range vent.
All these factors add up and could pose a potential problem.

All i'm saying is "be careful".

[Jason Roehl]

Just something to think about, but if it's a guest bathroom, quiet may not be the way to go. A fan that makes some noise can help disguise some of those, um, unpleasant noises being made in the, ahem, regular use of the facilities. I hate having to use the WC as a guest somewhere that has a hollow-core bathroom door, large gap at the bottom, no fan, and located near the living area, where everything can be heard on both sides of the door. :eek: :rolleyes:

[Sonny Edmonds]

... has become uncommon to find.
Matt has a very valid point about ventilation considerations.
A couple of thoughts to bear in mind:
When replacing things like a forced air furnace, ours went into the attic, from being in a closet. Actually, we replaced the AC unit, and with that I had the entire system replaced and updated.
The only things "in" the living space are the return in the hallway (central point of this home), and the vents feeding each area or room.
When Mike (HVAC contractor, Friend of the family) installed our system, I asked him about a fresh air intake. He said most people don't even consider that. But suggested I simply put a 6" inlet just before the filter box on the return, and feed it from an additional roof vent.
That establishes a real fresh air intake for the living area that the bathroom fans can draw air through to make up what is being exhausted outside. And that make-up air is filtered. ;)
It also allows the system to draw in air when running to create a positive pressure inside of the house. That was my main interest in bring in fresh air.
It will only be ounces, depending on the building, but it is fresh air being drawn in, conditioned (heated or cooled), and ventilating the house.
Moisture naturally occurs and is the cause of molds happening. Even if you bathe in the creek, your breathing and being inside your box/ tent/ outhouse will cause moisture. Ventilation can reduce/eliminate that from happening.
Fresh air in, old air out.
I live in a mild climate, but my shops have always had a roof vent to let rising air out. It keeps the shop dry.
So think about that make-up air, whether for your home or shop. Supply air for combustion and it won't back draft. Folks who run wood stoves or fireplaces, or coal burners or oil heating systems usually understand this. Better yet, move it outside of the living area.
Another nice benefit is the quiet of the furnace/AC unit being in the attic.
But get some filtered fresh air into your home.

[Dan Mages]

Just something to think about, but if it's a guest bathroom, quiet may not be the way to go. A fan that makes some noise can help disguise some of those, um, unpleasant noises being made in the, ahem, regular use of the facilities. I hate having to use the WC as a guest somewhere that has a hollow-core bathroom door, large gap at the bottom, no fan, and located near the living area, where everything can be heard on both sides of the door. :eek: :rolleyes:

Ummm... Thanks Jason, I guess.

Luckily both hall baths are far enough from the living spaces from the house that any loud noises will be covered. I think a solid core door and sound insulation may be in order for the future tho...

Regarding air flow. Our house is 50+ years old and is far from tightly sealed. I am sure any air removed will be easily recovered. Is a back draft a potential issue with oil fired furnace and hot water systems? I do know that there is a barometric pressure valve on the exhaust ducts for both the furnace and water heater.

Dan

[Cliff Rohrabacher]

If you can do it, a remote fan setup is going to be much quieter than a ceiling unit [...] They provide excellent ventilation with minimal noise


Yah what he said. And you can get a much higher CFM and Delta P fan if you mount it on the roof or attic.

I just did a kitchen exhaust fan. I got the Wolf roof mount. I gotta put weights on the cast iron pans to keep 'em down when the thing is on high. It nearly pulled the flooring out. :-p

[Jim Becker]

Cliff, my 48" Broan hood is rated at 1200 CFM...which was required for a range with a grill. It will move air big-time when you have the "peddle to the metal" on the speed control! I exit via the wall, however, through a custom fabricated duct that's contained in a joist bay.

[Joseph Hadley]

I was involved in a renovation for an inn, wherein I had to find an affordable and quiet fan for 20 bathrooms. I compared the Panasonic to the Broan and found the Broan Ultra Silent series to be more than adequate and much cheaper. I imagine the inline remote fans are quieter, but the 80CFM and 110CFM Broan Ultra Silents worked well and at 0.8 to 1.3 sones (audible but definitely not a nuisance). I installed one of these units in a public bathroom at the Inn and it worked for 4 years non-stop (24/7) before needing to be replaced.

I remember paying about $100 to $120 per fan over the years.

[Glenn Clabo]

Just a point from someone who has done an excessive amount of research on noise...
Most high volume fans air flow noise will overwhelm the motor noise. The thought that a remote fan motor is worth the extra expenses and is notably quieter...is a fairly common misconception. At very low speeds...it is. At mid to high speeds...it simply isn't. One of the keys to reducing noise is not using screen filters...but large deflectors.
I actually experimented with both fans...in a kitchen remodel...and had to eat my own misconception.

[Matt Ocel]

... has become uncommon to find.
Matt has a very valid point about ventilation considerations.
A couple of thoughts to bear in mind:
When replacing things like a forced air furnace, ours went into the attic, from being in a closet. Actually, we replaced the AC unit, and with that I had the entire system replaced and updated.
The only things "in" the living space are the return in the hallway (central point of this home), and the vents feeding each area or room.
When Mike (HVAC contractor, Friend of the family) installed our system, I asked him about a fresh air intake. He said most people don't even consider that. But suggested I simply put a 6" inlet just before the filter box on the return, and feed it from an additional roof vent.
That establishes a real fresh air intake for the living area that the bathroom fans can draw air through to make up what is being exhausted outside. And that make-up air is filtered. ;)
It also allows the system to draw in air when running to create a positive pressure inside of the house. That was my main interest in bring in fresh air.
It will only be ounces, depending on the building, but it is fresh air being drawn in, conditioned (heated or cooled), and ventilating the house.
Moisture naturally occurs and is the cause of molds happening. Even if you bathe in the creek, your breathing and being inside your box/ tent/ outhouse will cause moisture. Ventilation can reduce/eliminate that from happening.
Fresh air in, old air out.
I live in a mild climate, but my shops have always had a roof vent to let rising air out. It keeps the shop dry.
So think about that make-up air, whether for your home or shop. Supply air for combustion and it won't back draft. Folks who run wood stoves or fireplaces, or coal burners or oil heating systems usually understand this. Better yet, move it outside of the living area.
Another nice benefit is the quiet of the furnace/AC unit being in the attic.
But get some filtered fresh air into your home.

Sonny -
Thanks for the back up.;)

[wyatt wright]

I think the most important step in the process to improving your ventilation system is to learn more about bathroom fans (http://www.bathroomfanexperts.com). There are many options you can choose like a wall mount fan, traditional ceiling fan, or even a central ventilation system. Getting more information on each type of fan may help you figure out the best solution as to which kind to install in your own home. It is important to find a good ventilation system to avoid too much moisture which can cause mold. Let me know what you decide on as it may help me when I remodel my bathroom after the summer!

[Dan Hintz]

Can't remember what I bought when I started the bathroom remodel several years back, but quiet was what I was after for a reasonable price. I remember it being very reasonable in price, and the thing is so quiet it has to be dead silent in the room before I know it's on. Even while talking you can't tell it's running. Squirrel cage fan, I seem to remember something around 100CFM, give or take.

[David Larsen]

Just something to think about, but if it's a guest bathroom, quiet may not be the way to go. A fan that makes some noise can help disguise some of those, um, unpleasant noises being made in the, ahem, regular use of the facilities. I hate having to use the WC as a guest somewhere that has a hollow-core bathroom door, large gap at the bottom, no fan, and located near the living area, where everything can be heard on both sides of the door. :eek: :rolleyes:

Sounds like something to do with your diet! LOL

[Brian Elfert]

I decided to have the HVAC contractor install fans in two bathrooms that were only roughed in when my house was built. There was no room in the basement bathroom for a regular ceiling mount fan. The contractor did a remote mount fan.

The remote mount fan is no quieter than a normal vent fan in my case. They put a Panasonic in the other bathroom and it isn't all that quiet either. I don't think I'm being too picky about the noise.

[Larry Edgerton]

I usually have air to air exchangers installed in most houses I build as I am extremely anal about houses being tight. Outside air intakes for furnaces/boilers and intakes to all firplaces behind the glass doors. I like to see timers on bath fans so it is not left on to blow expensive heated air outside when not needed. I like a house that every closed interior door rattles when the outside door is closed. Then I know I have done my job.

Here the cold can be extreme, so what we need is different from somewhere in say, Missouri, where the temps are more moderate. I have pressure tests done on homes to find unwanted leakage, and take great care to get rid of them all. I like Canada's system of makeing a house pass a pressure test to get final inspection. We need that here to weed out some of the lessor builders. In an article I read it said that an average Canadian home has a hole the a basketball. The average American home has a hole the size of a 8x8 garage door! Exchanging air in the average tract home is not an issue, the builder already took care of that for you.

Some people say I build a home too tight. I just laugh. I would rather take steps to control the exchange of air than have it a 24/7 condition. For example I have the air to air exchangers programed to run when people are present, and off at time when no one is home. Same goes with water heaters, why heat water when no one is there to use it or they are sleeping? I cut my gas bill at this house by 25% by putting my water heater on a cycle that heats it in the morning before we get up, turns it off when we are at work, on it the evening, and off while we are sleeping.

So.... Energy efficiency has to be considered as well as air quality, it is our civic responsibility to do better in my opinion, and the benifits are less money thrown away unneccesarily for no gain.

Just my random thoughts.......

[Larry Edgerton]

Oh!

This conversation did have a benifit for me! I am going to check out and see if I can tie my bath fans/kitchen vent in my new house to my air to air exchanger......

[Brian Elfert]

All houses in Minnesota are required by code to be extremely air tight, but they are also required to have air to air exchangers. I have timers on all of my bath fans so they can be run for a few minutes after someone leaves the bathroom.

[Dan Hintz]

In an article I read it said that an average Canadian home has a hole the a basketball. The average American home has a hole the size of a 8x8 garage door!
I imagine this was said tongue in cheek. I expect the average American home has several basketballs worth of holes... but 64 square feet? Drama much?

[David Larsen]

I imagine this was said tongue in cheek. I expect the average American home has several basketballs worth of holes... but 64 square feet? Drama much?

Taking into account an average of all homes including most of the older homes that don't have insulation, minimal insulation, single pane windows, chimneys, 2 x 4 walls, etc, it might not be far off. If it is only new construction, then 64 sq. ft. seems exaggerated.

[Dan Hintz]

A 2'x3' window with a huge 1/4" gap (i.e., you could see your neighbor through the gap) running around the entire window makes up a mere 0.2 square feet of space. This itself is unbelievably unlikely to happen, not to mention physically impossible (floating windows, anyone?). A 3'x7' door with the same gap would amount to double this. Let's say 5 doors in the house, and 30 windows... ignoring all else, that's still only 8 square feet of space.

Real numbers (say, a 1/16" gap along one side of a window, for example) make the statement seem even more absurd... you're likely to find 1/16" gaps around a lot of vents and such, but I think you'll agree the numbers don't quite add up.