15 February 2011

Green in Action: Bathroom Vent Fan Timers

Yesterday I wrote about our humidity-sensing bath vent fans. (In sum, we have two of them, and they've been a big disappointment.)

Today I'm going to write about the other piece of technology we are using to "green" up our bath vent fans: timer switches. Instead of regular light switches that we turn on before we get in the shower and turn off some time after we get out, these switches have a built-in timer that can be set for anywhere from 5 to 60 minutes (plus a regular "on/off" setting):

See the red dot to the left of the 15-minute mark? Pressing the button once on the way into the shower will ensure that the fan stays on for some time after to ensure that all of the humidity is gone. (If you turn your fan off as soon as you leave the bathroom, it's likely that a lot of moisture will remain, but if you leave a modern, super-quiet fan on after you've left the bathroom, there's a good chance you'll forget about it and continue to suck conditioned air from the house long after the humidity level has returned to normal. And by "you," I mean me. There's a good chance that I'll forget to turn it off.)

The switch shown above, by Lutron, is easy to program (just touch the narrow buttons on the right to increase or decrease the set time). It's also easy to install, as it goes in just like a regular outlet, so it can easily be retrofit for existing construction and any fan (just remember to take all appropriate safety precautions when messing with electricity, or call in an expert).

The one shortcoming of this bath fan solution is that, unlike the (theoretically) humidity-sensing fans we looked at yesterday, you have to remember to turn it on. I give it a solid A.

(For anyone still interested in trying out the humidity-sensing option, I hear Panasonic has just released a humidity-sensing switch, which turns any fan into a humidity-sensing fan. I don't know if it has the same issues as our humidity-sensing fans -- which are Broan/NuTone -- but I'm enthusiastic enough about this technology that I'd be willing to give it a try.)


  1. You know I never really knew the purpose of those vents? I usually don't turn them on because I find them loud and annoying. Yeah for learning something new!

  2. Here's a really green vent: Open your window. Our family bathroom has no fan and has double glazing which means after every shower, no matter how cold it is, I have to open our window to let the fresh air in and the humidity out. Perhaps it isn't so green because I usually have the heat on at the same time...