Whole House Fan (Switch)

I create a SmartApp for a whole house fan (attached to a GE switch). It turns on the fan when

  • Thermostat is off
  • Indoor temp is > Outdoor temp
  • Indoor temp is > minimum temp in settings

Hi Brian,

Thanks for your good work! Is there any chance you could create a version please that does not involve a thermostat, as I don’t have one that is compatible and still would like to use my fan please. I use the Netatamo for temperature.

The other one that would be really valuable to me is being able to simply shut off my fan if the house reaches the desired temperature of 58 degrees. So, I turn on the fan before going to bed and would like it to shut off then the house is cool. Any way you know of of doing this?

Thanks in advance! I moved over from Revolv, Mi Casa before that and Homeseer before that, and am really liking SmartThings!

Andrew Blount

@happyfatguy try this. I haven’t tested it, but I think it should do what you want without requiring a thermostat. Also, this should turn off automatically when the house reaches the desired min temperature. It will only do so if it was turned on automatically by this SmartApp.

Hey! Thanks for your help. I finally got to the point of implementing it today.

Excellent app - I have been using it for a year now and it works great! GE has a new multispeed fan control - any chance of modifying this app so it sets the whole house fan to the appropriate speed based on temperature? Example : if temp is within 3 degrees of target temp fan switches to medium speed to reduce noise and prevent the constant on/off cycling which we have happening now all night long…


It’s certainly possible. I would need more details on the fan control and what commands it requires. I’m also not sure if the platform knows how to control it yet.

Thanks Brian - it’s ge model 12730. It’s used in the smart ceiling fan smartapp.

@Dianoga, any way to include a condition that a certain window (or set of windows) has to be open?

Also I wish there was a way that when I toggled the whole house fan switch on, it would automatically turn off my thermostat. Is that possible?


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Requiring an open window is a great idea. I actually added that functionality earlier this week. It hasn’t been released yet, but it should be in the nearish future.

Turning off the thermostat when the fan is turned on is also possible, but that isn’t something I’m likely to build into this SmartApp.

@Dianoga, just an idea, did you make the open window optional? I am not sure if it’s possible to accept the installation of the app without the definition of such a sensor but issue a warning instead when the app is about to run (“Starting in 2mins - please make sure you have a window open”)?

Brian (@Dianoga),

I am only trying to turn on an attic fan when the temp is above a set variable. I have found one that turns on a heater when too cold, but no luck finding turning on a fan when too hot. I will try to tweak your code, but if there is one already, can you point me in the right direction?

Thanks! Great work!!

You might be able to use an app designed for window air conditioners. I’m not sure if one exists already, but it seems like it should.

Take a look at this. I’m not using it but others are, and it seems to work for them:

Thanks to @amn0408.

Thanks @bravenel. The SmartApp is currently going through the approval process at SmartThings but you can get the latest code on github.

@hutchins79, you can use the app to turn on and off the fan (or any outlet or switch) based on a temperature setpoint (any sensor reporting temperature). You can make that setpoint dependent on what mode you’re in (home, away, etc.). I haven’t tested with only having cooling devices without any heating devices. Let me know if you run into any problems. At the minimum you can put in heating settings but not use the heating mode.

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Hi Brian (@Dianoga),
Were you ever able to add code to check for open windows? I was about to start poking around to add that to your code, but it doesn’t make sense if you already did it.

I think I’m also going to make the app lock to specific mode(s), that way I can have different settings for night vs day vs away.

Hi All,

I have an need where the Whole House Fan by Brian without the thermostat meets almost all I need. I have an attic fan (not a whole house fan) and am using the code with a temp sensor outside and one in the attic. I trigger the attic fan when the attic is above a minimum temperature and the outside temperature is less than the attic temperature.

I would like to add one more bit of functionality. I would like it to trigger the fan only when 1) the attic temp is above my setpoint (app does this already) and 2) when the delta between the outside temp and attic temp is greater than a value I set.

I am missing number two. I have cases where the outside temp is 102F and the attic is 103 and it will turn on. Not much will happen here. I would like to set the minimum temperature to say 95 but only turn on if the difference between the inside and outside is say 10 degrees so the fan can actually make a difference by pulling in substantially cooler air.

Is this something someone can help me code and modify Brian’s code?

Thanks all! I am new to this and love it!

This is awesome! I would love to see it tied to an open window and the GE multi-speed switch. I’m toying with the idea of a QuietCool whole house fan and trying to figure out some automatic venting.

At first I was going to try and have my Ecobee3 control it but I think overall having SmartThings control it is best. But as I type that it might be cool if Ecobee would show the house fan usage as part of it’s reports…

note update in my second post…


Hey Brian,
I am looking for something like this to monitor 2 different temp sensors and trigger a fan to vent out hot air from my garage (to save money on AC/electricity bill; same basic idea as a whole-house fan, but in garage; will eventually be doing something similar for the attic as well, but starting here first).

Is there any chance you would be willing to create a modified version (or show me how; or point me in the direction for where to go to learn how) of this SmartApp that doesn’t require the house thermostat (I had it all set up and just about to work, but then it wouldn’t work, because I don’t have a smart thermostat, and don’t need it in this particular project anyway)?

In my case, since this will be in my garage, the house thermostat won’t be involved. So, I just want the other parts. i.e…

  1. Monitor two temp sensors (one will be inside, at the hottest part of the garage, and the other outside; possibly just using the SmartWeather Station Tile which is already configured and ready for use in my ST system)
  2. If outside temp is lower than inside temp, turn switch on.

I already have all of the smart and dumb equipment that I need for the project (including a dumb fan, smart temp sensors, and a smart power switch). All have been connected to and are functioning properly with my version 1 SmartThings Hub.

Also, I already have a thread for my project (Dual Temp Monitoring Garage Cooling Fan System). So, I am already in the process of refining what’s all going to be involved. Now I just need to get the SmartApp part figured out, and your app looks like the closest thing to what I need among apps that are already out there, ready to go.

If I can get some help with this SmartApp aspect, I could begin saving a little money (less heat in the garage means less heat in the bedrooms above it and the rest of the house it is connected to, which means less electricity needed for AC to keep the house cool) in the very near future. :slight_smile:

UPDATE: Actually, I think I got it figured out.
I just copied the code for your SmartApp, identified the portions that I thought weren’t needed (including those relating to both the thermostat and the windows/doors), removed them, resaved, and republished (for just me, of course). Now it is working! :slight_smile:

So, thank you VERY MUCH!!!
This is so cool!

One more thing though…
Is it possible to configure it to trigger on a relational difference instead of just a pure difference?
e.g. instead of triggering on whether or not one temp is higher/lower than another, can it be more sophisticated and trigger on the temp of one being ‘at least’ 5 degrees different?

I don’t know if it actually matters much, but I’m thinking it may help minimize the time spent running the fan when the benefit would be negligable…or is it definitely better to just have it based directly on the higher-than/lower-than idea?

I recently wrote just such an app for the very same reason. Funny thing is that I discovered that the exhaust fans I have are actually worthless, and don’t reduce the temperature at all. Boohoo.

The app, Garage Vent Fans is on Github: