Must be product review day! Some friends just had a question about what fan to get for their bathroom. Great question.
Bath fans are important because they can remove the tremendous about of water vapor created by showing and bathing before it has a chance to create mildew or mold issues. And they can be part of your home’s overall ventilation and indoor air strategy.
Too often, though, the cheapo fan—rattle boxes or noise makers, I call then—make a lot of noise, but don’t really move much air. And some older fans can suck a lot of electricity even while they’re not helping much.

Photo from www.panasonic.com
We use the Panasonic Whisper Series fans. First and foremost, they work! They have a great energy-efficient motor that really moves air very close to the nominal rating. And as the “Whisper” implies, they’re very quiet—some models you really have to listen hard to hear at all. And they’re reliable. They are built to last and run a long time—continuously if needed. An excellent choice.
I should mention that regardless of the type of exhaust fan you use, the fan should be ducted to vent directly outside. Do not vent them into your attic—that’s a potential mold farm waiting to happen. And even venting out a soffit isn’t a great idea, especially soffits designed to pull air up into the attic.
Thanks,
Mike
Addendum, Sept. 11, 2009: I’ve just finished an initial evaluation of Renewaire’s new bath fan line, and it appears every bit as strong as the Panasonic line. I can recommend it, too.
Tags: bath fan, energy-efficiency, green homes, GreenHomes, IAQ, mildew, mold, panasonic, Renewaire, review, whisper
July 29, 2009 at 5:36 pm |
A Note on the Panasonic Whisper Green bathroom fan: Great product, but I found mine to be a little noisier than expected and not as quick at removing moisture and odors as I’d like. I asked a Home Performance expert about this and he said that he installs a 4 inch to 5 inch duct fitting at the outlet and uses 5 inch flexible duct instead of the recommended 4 inch ducts. To their credit, Panasonic does insist that to reach max. efficiency one must install rigid ducts and not flexible, but who does that? I like the HP expert’s recommendation, although I haven’t personally retrofitted mine yet. Will post when I do. Best…
July 29, 2009 at 6:19 pm |
Hey Leif. Sorry about the bad experience. We haven’t had this issue–and we’ve been installing these for at least 10 years. Checking the airflow through the unit is straight forward–your home performance expert should be able to do it. You can even get a pretty good idea using the “garbage bag method”. (See the description/calcs from Bob Davis, et al, slide 28 at http://www.affordablecomfort.org/images/Events/15/Courses/419/Davis1_TAM04.pdf). Check the flow to make sure it’s near it’s rated capacity.
Also, verify the sizing of the fan is right for your bathroom. Panasonic has some simple tables you can use. Another thing might be the duct configuration. We do try to use rigid duct wherever possible–and you should NOT sette for vinyl. It’s too easy for it to tear, degrade, or get chewed through by critters, and then you could develop a should moisture issue inside your house–in a spot where it’s hard to see before it does damage. In my own home I used aluminum flex the the gymnastics getting out of the fan and to where a straight run was possible.
Sorry we’re not in your area, or we could tackle it for you. Good luck!
September 2, 2009 at 9:38 am |
[...] in July, I mentioned my preference for the Panasonic bath fans. Well, Renewaire, a company out of Madison, Wisconsin, has introduced a very promising line. I [...]
November 7, 2009 at 10:33 am |
[...] also notice in the picture an ENERGY STAR labeled Panasonic bath fan. It’s quiet and efficient and really gets the job done. In this particular project, it [...]
July 25, 2010 at 6:24 pm |
[...] talked before (maybe putting the cart before the horse?) about the Panasonic and Renewaire bath fans that I like. Excellent choices. Keep making good choices by [...]