Attic exhaust fan control

(Pete Molina) #1

I have an exhaust fan in my attic that currently only has an on/off switch. I’d like to be able to have it on a timer, but also would love to integrate it into my SmartThings. I was looking at getting something like this replace the existing switch. I’d like to retain the ability to turn it on (timed) at the switch. Are there any devices capable of handling both?

(Convinced ST will never be unbroken…) #2

I know of none… possibly because a SmartApp can handle the timer function with any switch.

Or better yet, tie it to a temp sensor to turn off when the house cools off.

(Chrisb) #3

Yeah there’s a SmartApp out there that someone wrote that will automatically this your fan on/off depending on if outside temp is lower than inside temp.

I used to have a manual timer on my whole house fan. I just put in a z-wave switch and set it up to automatically turn off 2hours after it’s turned on. This is quite easy to do. It’s harder to do it for different times without changing settings a bunch so if you like to set different times often then this wouldn’t really work. But if it’s a situation where you typical set it to 1 hour 95% of the time, then this would be an easy thing to do.

(Pete Molina) #4

Can I use just a normal zwave on/off switch? I thought, for some reason, that normal zwave “light switches” weren’t designed to handle the load of a fan.

(Convinced ST will never be unbroken…) #5

On/Offs will, dimmers won’t.

(Chrisb) #6

Yeah… what he said. :smile:

There is the potential that if your fan draws a LOT of current that it could be too much for the switch and could potentially damage it, but I have an older fan… at least 20 years old, so it likely isn’t very efficient. I swapped out the switch about two weeks ago and I’ve been using it a lot lately. So far my switch has been operating just fine.

(Convinced ST will never be unbroken…) #7

If your fan is plugged into a standard 15A outlet, you’ll be ok with an on/off switch or appliance outlet (they’re designed for that much current).

With that said, I have several 20A circuits wired for areas like my HT system, and that’s too much if that extra current is actually drawn. Check your breaker box for the supply breaker to your fan. If it’s marked 15A, you’re good. If it’s 20A, you may need to go with some kind of relay setup.

(Pete Molina) #8

It was in relation to dimmers (related to ceiling fans) that I was thinking of, so I appreciate the clarification on that. I think I have an extra switch around here somewhere that I can pop in there (after I figure which breaker actually controls it). I already put a temp sensor in the attic, so I will tie it to auto-turning on the fan. Thanks for the info.