Bathroom fan control - building a better mousetrap

Other Devices & Integrations Lighting & Load Control
1

Backstory: I’ve been on the fence on whether I want to automate my bathroom fan control. The general use cases for bath fans are odor or humidity control.

I was hesitant to use a general Z-wave binary switch, while this would work easily for the humidity control use case (humidity sensor in bathroom is tripped, turn on fan, humidity goes below threshold, turn off fan, etc), day to day use, say when someone wants to turn on the fan for 5 minutes and leave, won’t be as intuitive.

Yes, I know I could program some PLEG logic so that if you toggle the switch a certain amount of times you could then start a countdown timer, etc, etc. But this won’t be known to a guest in the house.

I’ve settled on using Cooper RF Aspire devices throughout my house (Except where I can use cheap GE binary switches). I like the looks and functionality of this timer control: http://www.cooperindustries.com/content/public/en/wiring_devices/products/lighting_controls/timers/aspire_timers_9590_9591.html

This timer is perfect for the daily ventilation and humidity control use cases. Short 5 minute intervals for quick ventilation, up to 60 minutes for showers. It’s those times when someone forgets or is not use to using fan control that I want to protect against humidity/mold build up.

Then it dawned on me: this type of timer switch uses a a mechanical relay for load control. Because of that, I can put another relay across it to provide a safety backup in case the humidity goes up and the no one turned the in wall timer on. One of these should be able to fit in the wall box to supply power to the fan when needed: http://www.amazon.com/Aeon-Labs-Aeotec-Z-Wave-Edition/dp/B008VWAPU4/ref=cm_cd_al_qh_dp_t

I already have a Aeotec 4-in-1 sensor in the bathroom to detect the humidity.

So now I should be able to have the best of both worlds, intuitive and easy local fan control anyone can use, and failsafe humidity control when needed.

Has anyone else ever tried this?

-TC

2

I’ve never tried it, but your logic is sound. It should work just fine.

3

This is a great idea, and something I think I will be doing as well!

4

My solution to this (that I haven’t implemented yet) in my master bath (which is likely just specific to my case due to my setup) is as follows.

Background:
There are 5 switches in this room. 1 main lights, 1 shower lights, 1 tub lights, 1 vanity lights (not used as mirrors cover them for now), and one exhaust fan.

Potential solution:
When “shower lights” switch is on, turn on exhaust fan until 10 minutes after it is turned off
When “exaust fan” switch is turned on manually, keep on for 15 minutes (I may vary this)
When “tub lights” switch is turned on keep fan on for 5 minutes after it’s turned off

Now, for some of my lights, my Fiance just doesn’t turn them off. She’ll turn on the shower lights, but not turn off the main lights, so in this instance I am going to also add a rule that when the “main lights” are turned off, it will turn off the shower lights. I will NOT be doing this for the “tub lights” because I can see times where she sets those lights low and turns off the other lights. I may set up scenes to handle this where I use a MultiSwitch to determine if I should auto turn off the “tub lights”.

I think your way is probably a bit easier and it might actually be better, but I wanted to offer my way up with only using the z-wave switch.

To be clear though, because I’m not sure how you are planning on wiring it, are you basically going to wire the microswitch and time in parallel?

                 LINE
                   |
     ____________________________
    |                           |
Microswitch                    Timer
    |                           |
    _____________________________
                   |
                  Fan

Is the above correct? this way either one can provide power? And if so, what are the consequences of back-feeding power into the two devices when the other is on?

Or are you actually talking about opening up the timer switch and modifying it with leads that go to the microswitch?

5

@SirMeili, you are correct. Both devices are binary switches that use internal micro-relays for the load current path. It’s just like two mechanical switches wired in parallel, either one can supply power. Essentially a logical OR condition.

If they were active load control, like a dimmer, that use active circuitry to control the load current, then there might be an issue.

-TC

6

I don’t need a better mouse trap … the rodents have left the building :wink:

I almost never touch a switch in my house. I have wired motion sensors everywhere that control the Lights an fans in all of the bathrooms.
The user can override them … but don’t usually need to.

Behavior is time of day dependent. All get automatically turned on and off. I have thought about a humidity sensor … but have not needed it.
i.e. just a little over night light level late at night …

And yes they are based on PLEG

7

Unfortunately Richard, I just spent >$100k repairing the interior of my home due to Sandy… punching holes back in the walls for wired sensors has zero WAF.

I’m not sure how you can have proper humidity control without a sensor. Most experts agree you have to have the exhaust on for 20 to 30 minutes (a manual approximation) after a hot shower. We do that now, but of course the teenager will forget to turn off the fan and then I’ve got one running the whole day until someone comes home. I pay the highest electric rates in the country.

Without a timer control or humidity sensor, how would one get a fan to stay on for say 45 minutes instead of 5 minutes?

8

Put a zwave switch for the light. Then a zwave switch for the exhaust fan. Turn on fan when humidity exceeds a threshold. Shut off x minutes later. Turn on fan whenever light switched (ie use light on as a trigger to turn on the fan) on for y minutes. Maybe x=30, y=5…

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9

@CuriousB, I already thought about those use cases. Not crazy about turning on the exhaust fan every time someone uses the bathroom, whether they need it or not.

I also like solutions that don’t have to rely on a central controller unless necessary (in case the controller goes out). Case in point, I’ve been installing Cooper RF Aspire devices, and their ability at direct associations is awesome. Hence why I’m leaning towards my initial idea of a local timer with a Z-wave override for fan control if necessary. But I appreciate the suggestion and I’m keeping an open mind about this before I settle on a final solution.

10

I have been wanting to put a water meter counter in for my automation. I am only have rain water collection… Water usage could be used to change the timer period.

11

Well let’s take this further. A water flow sensor in the shower hot water line and a weight sensor on the toilet. If the shower goes on turn on the fan for an hour. If the toilet is triggered 10 minutes… Well maybe 20 minutes…

I put one of these in my bathroom several years ago. I call it the mother in law switch. For whatever reason people don’t like to switch on fans. I took the option away…

http://www.iaqsource.com/product.php/fantech/fld-60/?product=112151

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12

@TC1 - I misunderstood your intent. I thought you planned to wire the time to the microswitch as below:

             Timer
         /             \

Line ==| |
\ |
====MicroSwitch===Fan

I’m confident that either way would work fine. But with this method, Vera will always be aware of the fan’s state. With @SirMeili’s method the fan could run for 30 minutes without Vera being aware of it. Not that it would matter…

13

I was going to use cold water … whole house usage … If delta usage is > XXX and bathroom activity … I infer a shower … set fan timers appropriately.

14

Speaking off… I wish the prices would come down on electric water valves. I really do want to install a mainline valve that could be triggered by a water sensor. Last thing I need is my new wood floors or base cabinets being ruined by a pipe/hose leak.

15

Those valve tend to restrict flow … you might notice when filling a tub or washing your car.

16

As noted earlier I do turn on fan every time the light is turned on by my dedicated light/fan delay switch I mentioned earlier. I combined this with newer super quiet fans so you don’t get the rev’ing of the 747 engine for the fan noise.

I understand the sentiment to not have the controller intermediate all control aspects of a home. I was that way too. But over time I’ve come to see Vera is highly reliable. I wish my Comcast data service were so reliable.

I have actually removed timer switches for my various outside lights and swapped to Vera controlled switches. Now I have Vera turn on outdoor lights at 20 minutes after sunset and off at 11:30PM every day. I don’t have to worry about daylight savings time, changing sunset throughout the year, reprograming individual timers after power failures and so on. Vera just handles it. I can also override and control the lights as I please with my cell phone.

I find the true power of Vera is in chained events. My wife thought this HA stuff was just me playing with a new toy. That was until I implemented a scene such that when she enters the deadbolt code on the garage keypad the deadbolt unlocks then the alarm systems automatically disabled. If its after sunset a few lights go on inside to welcome her home.

17

Interesting. What if you oversized it? Let’s say your normal water supply is 3/4" pipe, you buy a 1" valve control, and use some coupling adapters to put it in inline?

18

Yup, this scenario is the first one I setup when I got the Vera, some Schlage locks, and some GE switches. If it wasn’t for this one hitting the WAF home run, I wouldn’t be chatting with you folks ;D

19

I would recommend oversize … Unless you already have flow restricted service.

20

Talking about exhaust fans, is it possible to use the wall switch to trigger a set delay before the fan is turned off? The idea being that when the wall switch is turned on, the fan turns on normally, but when turned off, it runs for an additional 15 minutes.

I can’t see a way to make the Aeotec module ignore the physical switch, in effect making it a soft switch to trigger scenes. Anyone with ideas on how to do this?