PV Bathroom Fan

So we’re thinking of installing ventilation fans in the bathrooms — the window just doesn’t cut it for steam nor stank. Electrician can cut a hole in the ceiling, but says we should hire a roofer to cut the roof hole. Does it take a Ph.D to cut a hole in a roof? We can’t get one person qualified/willing to cut both holes and wire it up?

If we want to be able to control the fan independent of the light, need to run wiring down through the wall – a tedious job, and Electrician Dude says it’ll take all day to do both. There’s got to be a better way. Gave Berkeley Solar a call (the guy I talked to was really helpful, BTW), to see if there might be a way to power the fan from a PV cell and switch it on from a pull-chain. You’d think a unit like this would be available pre-fab, but no dice. Will have to assemble a kit from scratch.

$35 – 300W inverter
$35 – charge coupler
$50 – motorcycle battery
$300 – 50W photovoltaic cell
$100 – consulting fee to work out the whole kit, make sure everything plays nicely together
$20 – mounting brackets, switches, etc.

In other words, no savings over paying Electrician Dude to wire the wall. Except that it would be a fun project and have some geek cred. But we’re talking about a circuit that runs, what, 30 minutes a day?

If any entrepreneur wants to put together a self-contained solar unit like this, with integrated fan, for a fraction of the cost, I’d think you’d find a sizable market.

Music: Mike Watt :: Pluckin’, Pedalin’ and Paddlin’

16 Replies to “PV Bathroom Fan”

  1. If you’re going to go for geek cred, what you really need is a humidity sensor to power on the fan automatically. To heck with a pull chain! Besides, some of the really quiet fans are so quiet you will easily forget that they’re on and your fan could be running all day, or until it drains down that motorcycle battery….

  2. Great idea Dylan – I love it.

    Of course an alternative, which would not require wire down the wall, would be to attach it into the light’s wiring up in the ceiling, so that it goes on whenever the light is on. Or put both on a timer.

    A friend also suggested a wireless RF switch that would tallk to a small junction we’d install up in the attic. That way we could have a separate switch in the wall for it, but still not have to tunnel the wall.

  3. Putting the fan on the existing light circuit, and replacing the light switch with a timer switch, would probably be the simplest solution of all, and one you could easily do yourself. In fact, if your attic is well ventilated you may not even need a roof vent… our bathroom fan vented into the attic for years with no real ill effects. I disliked it, but I can’t say I observed any problems.

    If you do go with a roof vent, though (and that’s the *right* way to to do it) you probably do want a roofer. Unless you have expertise with roofing, you’ll wind up calling a roofer anyway, when it leaks this coming winter…

  4. Not sure I like the idea of venting steam into the attic, even with roof vents – that would seem to encourage mold growth up there. We don’t have roof vents now, but installing them is also part of the current plan, since heat build-up is prematurely aging the roof tiles. So yes, that’s a good point – we’ll be hiring a roofer anyway, so if we can sync up the two jobs, then there’s no hassle or overhead in hiring two people rather than one.

    Re: A humididy detector to trigger the bathroom fan – wouldn’t do the trick for stank, unless someone was capable of generating a whole lot of humidity at the same time!

  5. The bathroom in our new apartment has a fan that comes on at the same time as the light. I find it very annoying to go in to brush my teeth and have to listen to the fan running.

    I like the idea of a fan triggered by a humidity detector. I never knew how long to run the fan to get rid of all of the humidity in the bathroom. Also, I never found running the fan got rid of the stink that quickly.

    We had our roofer at our old house cut a hole in the roof to extend a plumbing exhaust pipe. He also put a cap on it to keep the rain out. He didn’t charge us anything extra for that.

  6. Gattaca, I think you might benefit from just replacing the fan unit itself. A newer Panasonic will run nearly silently and is probably capable of moving up to 4x the amount of air as an older fan, which means it would probably do a much better job at removing stink (though you do have mneptok to contend with, and that can’t be pretty).

    I only mention Panasonic because a relative has one and I was wowed by it, then a contractor recommended the same model to us just a few weeks later.

  7. Scot,
    Unfortunately, we live in an apartment right now. I had heard about the Panasonics when I was thinking of replacing the fans at our old house.

  8. Another venting option, whether for a solar or conventional fan would be to vent it to an existing vent under the eaves, or to cut a new one yourself. (definitely a more doityourselfer manageable and less disaster prone process than going thru the roof proper). Dont vent directly into the attic.

  9. I don’t like the idea of venting into the attic at all for reasons given above. My attic has vents under the eaves. They are a bit small but one could be enlarged easily enough. This could be a much easier way of providing the vent. I would use a flexible pipe to take the steam straight out.

  10. When we bought our house it had bathroom fans dumping moist air directly into the attic..and i didn’t care for that either Scot. My solution (from This Old House) was to run 4″ insulated flexible ducting along the ridge of my attic and “t” off that into each bathroom fan housing. Works great. I’m finishing a remodel of the main bathroom and plan to install a humidity sensing fan/light/nightlight combo rated at 1.0 sones (very quiet). I’m paranoid about mold growth since we have young kids, so this is the best option as far as i’m concerned.

    Stank? I’d suggest keeping matches and a few scented candles near the throne. The phosphorous from the matches will help neutralize the odor initially, and when the candle is blown out, the wick will be starved for oxygen and will steal from the surrounding air in an attempt to save the flame;) Good luck!

  11. yep..straight out the gable vents at the peak of the roof.

    Panasonic may in fact have a good product, but their customer service is about as helpful as a tightly pressed coil in the porcelain. I’ll NEVER buy a panasonic product (or anything from the matsushita corp) as long as i live..and i promised customer service that i’d spread the word. Take THAT matsushita!! My work here is finished.

  12. Hi fellas – I’m a lady searching for answers on bathroom ventilation fans..

    I had a ac/ductwork guy come out to give an estimate on how to fix the lame fan in my first floor Master Bath. He said that he’d put in a more powerful fan and a wider circumference (4 in instead of 3in) ducting up to the attic, where he said the vents in the attic would pull the steam outside. I simply do not want the steam to end up in the attic & hope that it travels out the existing vents; sounds like a recipe for mold in the attic.

    Do you think that I should just have someone install a more powerful bathroom fan, leave the 3 in ducting up to the attic, and then do what Danno did i.e. add flexible ducting from the opening of the existing 3 in ducting in the attic, up to the vents in the peak of the roof?

    Separate from that question, here’s another one: why can’t I just have the first floor Master Bath fan pull the steam up to the struts in the ceiling of the Master Bath, then have ducting go horizontally out the wall to the outside (instead of making the air travel all the way up to the roofline)??

  13. Must be ladies week! I have a bathroom fan challenge, too.

    My house is 120 yrs old with a flat roof. The only bathroom is one the second floor. There is already a fan vent in the roof over the bathroom but no fan in the bathroom! I don’t want more holes drilled or more switches (ie no electrical). I want a solar powered fan with a remote control or pull string. The roof has full sun light. So, all that is needed is a clean cut in the bathroom ceiling under the existing fan vent in the roof. There is no attic. Any ideas would be greatly appreciated! PS I live in Bucks County, PA.

  14. you could even do one other thing, connect ceiling fan to light wiring and be sure to buy one with a remote control. This way you just need ti provide power source and dont need to bother with controling ceiling fan.

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