• Share:
Prevent Mold with the DewStop Fan Switch

Control bathroom humidity more efficiently with a new type of humidistat switch that turns an exhaust fan on and off in response to changing humidity levels.

By the DIY experts of The Family Handyman Magazine

Remove the old switch

If you just turn your bath fan on when you start a shower and off when you leave the room, it doesn’t run long enough to remove excess humidity. If you leave the fan running too long, you’ll waste energy.

A new fan control switch called DewStop solves both problems. It calculates when condensation will occur and turns the fan on and off automatically to keep the humidity at an acceptable level. This computerized switch is a vast improvement over the humidistats that have been around for years. You simply replace the switch or timer that controls the fan with the DewStop switch. It’s available online at www.dewstop.com or from online retailers. If you’re replacing a double switch that controls the fan and the light, order the version that includes a light switch.

Caution!

Turn off the power at the circuit breaker box before removing the old switch.

Back to Top

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

    • 4-in-1 screwdriver
    • Electrical tape
    • Non-contact voltage tester
    • Wire stripper/cutter

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

    • Wire nuts
    • Fan Control

Comments from DIY Community Members

Share what's on your mind and see what other DIYers are thinking about.

1 - 6 of 6 comments
Show per page: 20   All

January 10, 1:24 PM [GMT -5]

I love this! I have one in each bathroom, I Highly recommend purchasing at least one.

November 20, 10:26 PM [GMT -5]

The automatic humidstat is certainly a good idea to reduce the usage of electricity as compared to not using any and leaving the exhaust fan always on. Another way is by ensuring there is enough ventilation in the bathroom through open windows and doors. This will keep the humidity out and prevent mold from thriving. Natural wind is a good alternative to using a fan during a bath and is even more energy efficient. Also, you can practice prevention methods by mixing 1/2 cup of bleach with 1 qt. of water and spraying onto your walls/tiles to keep the mold out. A similar mixture of 1 portion baking soda and 3 portions vinegar does the same trick. Try both and see which works better for your bathroom condition.

November 19, 3:39 AM [GMT -5]

The automatic humidstat is certainly a good idea to reduce the usage of electricity as compared to not using any and leaving the exhaust fan always on. Another way is by ensuring there is enough ventilation in the bathroom through open windows and doors. This will keep the humidity out and prevent mold from thriving. Natural wind is a good alternative to using a fan during a bath and is even more energy efficient. Also, you can practice prevention methods by mixing 1/2 cup of bleach with 1 qt. of water and spraying onto your walls/tiles to keep the mold out. A similar mixture of 1 portion baking soda and 3 portions vinegar does the same trick. Try both and see which works better for your bathroom condition.

August 25, 2:27 AM [GMT -5]

Yes! this is a better option but I want to add one point i.e., if we ventilate our house then moist air will become dry and hence mold will not form. By doing so we may breathe fresh air also which is good for our health. So i thing ventilate our house is also a best option.


mold remediation great neck

October 07, 12:23 AM [GMT -5]

Is it possible to add a single pole switch to run a vent fan? Right now i have one single pole that is running 2 recess lights and a vent fan I want add another single pole to operate the fan separately. The problem is that it is only one wire coming into the box and both of them are hot.Is this a possible project?

February 20, 8:46 AM [GMT -5]

i just put one of these into my teenagers' bath. It works as advertised, although it seems to take a long time to sense a shower (about 5 min). If you breathe onto it it will start in 10 sec. since this was a retrofit I added it to a 3-switch box. Beware that the switchplate holes do not match standard leviton, etc. stuff and need to be wallowed out. If you just use the switchplate it comes with (use it by itself) does not matter. I am remodeling a master bath and will add one there too.

+ Add Your Comment
closeX

Add Your Comment

Prevent Mold with the DewStop Fan Switch

Please add your comment
closeX

Log in to My Account

Log in to enjoy membership benefits from The Family Handyman.

  • Forgot your password?
Don’t have an account yet?

Sign up today for FREE and become part of The Family Handyman community of DIYers.

Member benefits:

  • Get a FREE Traditional Bookcase Project Plan
  • Sign up for FREE DIY newsletters
  • Save projects to your project binder
  • Ask and answer questions in our DIY Forums
  • Share comments on DIY Projects and more!
Join Us Today
closeX

Report Abuse

Subject
Reasons for reporting post

Free OnSite Newsletter

Get timely DIY projects for your home and yard, plus a dream project for your wish list!

Follow Us