Conserve Your Energy (and Your Home's) with Bathroom Fan Timers & DewStop Condensation Sensor

Earlier this summer, I finally noticed a pattern in my evening routine. At the end of a long day, after climbing into bed and settling my head on the pillow, a mechanical growling would emerge from the house's nighttime quiet.

Someone left a bathroom fan running and, for all I wanted to ignore it, our climate-controlled air was being siphoned off into the night (and had been for hours). I could either try to ignore the situation (though it felt as wasteful as leaving the fridge door open all night) or get out of bed and turn it off.

A separate trip to the hardware store brought me to the solution: a bathroom fan timer (Pass & Seymour's 7 Button Timer, ~$30). With an engineer dad and a teacher mom, I have been involved in home maintenance and improvements from an early age. The timer switch installation didn't seem much different than replacing a regular light switch, so I bought a model with automatic shut-off after 1, 5, 10, 15, 30, or 60 minutes.

With the kids napping and Dad on the phone, I installed the timer in our highest traffic bathroom.

Almost immediately, I noticed far fewer trips into the bathroom to turn the fan on or off. The kids liked using this switch, so they were happy to deploy it as needed (which had not been the case before), and the fan reliably turned itself off. Jim liked it so much that he asked that I put one in the downstairs bathroom.

The next day, GTR Technologies Inc. contacted us about reviewing their DewStop condensation-sensing fan switch with automatic shut-off. I had never heard of such a switch, but it seemed quite appropriate for a basement bathroom where the shower is used regularly.

DewStop (in center,with blue light) installed between
existing light switch and outlet. Top panel has sensor and LED,
middle button is manual on, and lowest button is manual off.

They sent me the DewStop FS-100 (presently selling for about $48 on Amazon). The installation was almost identical to the timer switch I had already installed. It took me less than half an hour from start to finish (the switch is in a multi-switch junction box, so it took me a little longer to arrange all the wiring and the switch controls into the box and level the switch so it fit under the face plate.

Now, if someone starts showering without the fan on, the switch activates the fan when the humidity reaches it. Our bathroom is long and narrow with the shower and fan at opposite ends of the room and the shower has doors rather than a curtain. This architecture means some humidity accumulates in the shower stall before the fan activates.The humidity is minimal, and dissipates soon after the fan is triggered. Also, the occupant can manually switch the fan on before taking a shower. As when the fan is triggered by the sensor, the timer will turn the fan off after 30 minutes. Both the DewStop and the variable timer have manual off buttons.

The condensation sensor seems most valuable in a bathroom where teens or adults regularly shower. Foggy mirrors and damp walls could be mostly avoided (distance between the switch and the shower may mean a little fog on the mirror right after showering). Jim observes that the switch is great for a guest bathroom because guests won't have to remember to start the fan.

We really like both timed switches. I'm always a little surprised when I realize that the run-time interval has already passed (whether it's 5 minutes upstairs or 30 downstairs). I hate to think how long the fans were previously left running before we turned them off. I can't speak to energy savings as I installed them at the beginning of this heat wave, but I'm sure the fans are running less with the timed switches (even with a 30 minute duration).

And, best of all, when I climb in bed at night, if I hear a ventilation fan running, I know it will turn itself off without my assistance. I love automation.

***Baby Toolkit is the collected reflections and independent opinions of some geek parents in the middle Midwest. Though we know one end of a screwdriver from the other, we're not electricians. While we received a free DewStop from GTR, we're under no obligation to mention it on the blog (much less say anything nice). We have no financial relationship with GTR or Pass & Seymour. We are Amazon affiliates, so a portion of purchases through our links helps cover the blog's overhead. We also podcast about board games at GreatBigTable.com.