DewStop Humidity Sensor Switch for Bathroom Fan, Condensation Control with Adjustable Sensor & Countdown Timer, Automatic Fan On/Off, White, FS-300

Update, late summer of 2019: The weather has been cooling off and we have been turning off the AC more often and opening the house for fresh air. The downside of this is that you can't control the humidity of fresh air and my Dewstop switches have been running quite a bit despite turning the humidity sensitivity all the way down. They sense the humidity coming in the window with the fresh air and activate. I finally contacted the company and was very pleased to receive a quick reply that the switches are designed to allow me to turn off the automatic sensing of humidity so that the switch acts like a regular, dumb, on/off switch. The procedure is, make sure the switch is off (no blue light), hold the main on/off button in for at least 15 sec. (The fan will come on when you let go, but just turn it back off, ignore that) This causes the switch to change modes. If the switch was automatically sensing humidity, it stops doing that. If it was in manual mode, holding the button will cause it to switch back to automatic sensing. This is the perfect solution to the problem. During this time of year, because I know I'll have open windows for awhile and plenty of fresh air ventilation in the house, I've set all my switches to manual mode. I can still turn on the fan with a push of the button, it just won't turn on by itself. When winter comes and I close up the house again, I'll revert them all to automatic mode. Well done Dewstop. Update summer of 2019: We are family that likes fresh air when the outside temps are comfortable. Unfortunately, this also means higher humidity levels inside the house. I knew I would have to adjust the switches for "summer mode" and this is my experience. Again, if you're a household that keeps the AC/Heat on year round with the house closed up, this probably won't be an issue for you. As the them outside temps come up and we start opening up the house more, humidity from the outside migrates inside. The switch doesn't know where the humidity comes from, just that its there and so the switch comes on. I turned the sensitivity all the way down, and the switches still come on. I looked in the troubleshooting guide and it talks about the electrical box enclosure. Basically, the box within which the switch is installed, has openings that allow air from inside the wall. This means that overnight, when the house cools down, the inside of the wall cools down also, and during the day when you open the windows and allow warmer air into the room, the switch is potentially feeling air that is slightly cooler inside the wall. The guide says to power down, remove the switches, and seal all openings in the box. However, that just means its now a seal box that is still not breathing to the room within which it is installed. I tested this idea by removing the cover plate so the box is open to the room, in less than an hour, the box had conditioned itself to the room temp and the switch stopped running constantly. So...not sure how to fix that problem. Light switch covers are not design to allow the box to breath from the room, and I'm not convinced that sealing the elec box with solve the problem. Bottom line, if you're purchasing this switch, recommend before installing it, that you seal the elec box first. If it does work, it will save you from having to do it later. So far, works perfectly. Comes on when condensation starts to form and doesn't shut off until the humidity is back under control. I read the negative reviews, and I can see how people might have difficulty with this product. Its sensitivity and automation will be affected by the static humidity in the house, which varies. I have electric heat, which is very dry. My current static humidity is around 45 percent. In the summer with the AC running, my humidity is in the 60s so I assume that I will have to adjust the sensitivity of the switch for summer. If we decide to turn off the AC and open the windows for fresh air, the humidity can get really high and if I don't adjust the switch for that, it will be kicking on often. Bottom line, the switch works great, you have to know the humidity in your home and adjust the switch to compensate for it. I ordered this one as a test, but am so happy with it, I'll be ordering more for the other bathrooms.

The control device is easy to install for those of us who are experienced in replacing wall switches and outlets. And imagine this: It works as described! When the humidity rises, such as after a shower, it runs the exhaust fan until the humidity drops to normal value. The setting for humidity control is adjustable, so if the default value isn't right for you, you can adjust it accordingly. The unit also has a nice push button which activates the fan for 30 minutes. So, say goodbye to the occasions of the fan being left running for hours and hours, or the instances of the fan being needed but was not used. The push button also serves to stop the fan while running if you wish. Overall, this is a very satisfying product because it works so well.

Really like the design. Fan would turn on once humidity reaches the set point, and shuts off once it drops below. Worked flawlessly, for about a month, then stopped working automatically. Now the switch only works if it is manually turned on, and shuts itself off after ~20 15 minutes, but I could have purchased much less expensive options for a simple timed switched, and wanted this switch so a bathroom exhaust fan would operate automatically due to on humidity level.

The bathroom I used this in had a spring-based timer that was often not used or the hour max was not enough, Droplets of moisture would be on ceiling all day. This product solved the problem. You need access to the black hot and white neutral. If the fan wires do not directly to box you will need another wire (lets say red) to bring the power to the fan. The device itself has HOT (black), NEUTRAL (white) and RED (FAN), and GREEN ground. You can download the instructions from their web site. Basically the device gets fan HOT from the black, and passes it on to its RED to turn on fan. I will not attempt or answer wiring questions. All I can say it works as advertised. I used a humidity gauge to actually monitor its operation. This has worked perfectly for over 2 years . It works exactly as advertised. Don't expect it to know the difference between a damp basement (if used in basement) and humidity from a shower or from a damp house from humidity from a shower. Apparently some reviewers don't understand that and complain. This product saved us from mold, wasting electricity. I will buy another one for my next bathroom project.

We have a small bathroom that was growing surface mold due to humidity build up. We first got a timer switch so you could select a time for the fan to stay on to remediate this surface mold problem. That worked well but we'd forget to turn it on. I really wanted to put a humidity sensing fan in but they are expensive and the affordable ones are less powerful than what we had or don't have a light. This then became our solution. At first I was worried it wouldn't turn on much because the sensor was half way down the wall and steam rises but the opposite is true. This turns on at the drop of the hat. We've adjusted and adjusted and no matter what we do, it turns on a lot. When we have our heater or AC on, this seems to mostly function well (within a minute of turning on the hot water for a shower, the fan switches on) however, on those nice days when we open the windows, there is often enough moisture to keep it running all day and night. We live in central Illinois so this problem would be worse in more humid areas. Additionally you can click it off when it automatically turns on but there is no time out for a long time of time so if it senses humidity again it will turn back on quickly. I'm looking around for another option with more range of sensitivity but for now we use this and just waste some electricity and/or have a sound machine on for some days out of the year.

A little about my situation: I live a few hundred feet from the ocean in Alaska, so my climate is cool and humid. My bathroom is pretty small. I like this gadget because it is makes it impossible to really drench the bathroom in humidity - the DewStop sensor kicks in and starts the exhaust fan, as expected. Even on the lowest sensitivity, it turns on after a minute or two of being in the shower. Great. What I don't like is that it stays on MUCH longer than is necessary. It is very expensive to heat my home in the winter, and this device keeps the fan on for a half hour AFTER I get out of the shower. Since it only takes about five minute to expel the humidity from my bathroom it means that for twenty five minutes I'm expelling dry, hot air from my house. I have additional bathrooms in my home and I'm unlikely to install additional DewStop devices in them because I don't like how long the sensor keeps the fan on. I'm also considering replacing this device with a standard switch. Also, as other users have stated, the fact that you have to unscrew the lightswitch cover before you can access the unit is a pain.

I was going to install a somewhat expensive, stand alone humidity detection unit…but it was going to be very ugly and protrude out. Instead I looked at this, and while I was little hesitant to trust my bathroom to such a small sensor, to its credit, it does its job wonderfully. At times the fan does not kick in when I am showering though -- it seems to sense the moisture much more when I actually open the shower door at the end, despite a lot of humidity (seemingly) being in the bathroom. It doesn't seem like the mirror fogs up though, so maybe it really doesn't warrant it coming on. There is a humidity detection dial that can be adjusted, so I may just need to tweak this a little more… though where it currently is sits just about as high as you I go without it staying on all the time. Nicely, if the humidity gets too high – whether I am in the bathroom or not – the fan will turn on. If I want to turn the fan on otherwise, it is very easily done by just pressing the button, which can also be set to stay on for a certain time before automatically turning off. I'm very happy with this unit; is low profile works wonderfully!

I purchase one of these in 2016, has ran fine for the past 5 years. Recently it has stopped turning on automatically, so I considered replacing it with another model, but based on the reviews of the Nutone and Leviton humidity switches, I'm buying another DewPoint.

This sensor is very easy to install and works great in controlling humidity in our washrooms. No more sweaty windows.

I have it for a year, it just don't work. The fan never start. I move the moisture sensitivity fully to the left and fully to the right and results are the same: Nothing!!! The timer switch is working fine. BUt if you want a timer, buy a timer, not that.

Looking for auto on auto off Fan sensor for months. Found this but read mixed reviews but took a chance and ordered. Had it for a few days now and it works exactly as described, great for my household and kids that forget to turn on Fan during long showers. Timer shutoff works great too, Very pleased.

It works very well i would definitely recommend it however you should look at your wiring because if you don't have a wire going directly to power your fan it will not work. The answer of attaching the black and red wires together does not work. It will work but only as an on off switch. The switch needs a neutral (easy enough white wire) it needs its own power ( black wire). The red wire sends the power to the fan. That's why you need a wire that goes directly to your fan.

Bought one of these to control the bathroom fan in my previous house. Loved its ease of operation, and customizing controls — set and forget — so much, I bought this one for the fan in my new home.