Smart Switch needed: No Neutral, must work w/ SmartThings Hub

I have a regular switch in a closet which switches on/off a gable (attic) fan. No neutral wire is available. I only have a SmartThings hub. I am having a terrible time finding a Z-wave / Zigbee device that meets all of the following requirements:

  • integrates with my SmartThing hub without requiring an additional special hub
  • does NOT require a neutral
  • can be just a relay - I could be ok with sacrificing the actual physical switch, keeping it would be preferred though

I really DON’T Want to add a neutral wire.

I have looked and looked and have just about given up and fairly sure I need to run a neutral because the few no-neutral options are smart switches which don’t play with SmartThings.

Thanks in advance

I don’t know what how many watts/amps is needed but there are some no neutral Z-wave switches from Inovelli and some no neutral Zigbee switches from Aqara. All Aqara products say that they need their hub, but actually they work with SmartThings. Aqara is being added to official edge drivers

Aqara Smart Light Switch (No Neutral, Single Rocker), Requires AQARA HUB, Zigbee Light Switch, Remote Control and Set Timer for Home Automation, Compatible with Alexa, Apple HomeKit, Google Assistant https://a.co/d/71vhjXN

I would recommend Inovelli at this time, as Aqara is new product

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I believe all no-neutral switches are designed for lower lighting loads, not the higher wattage and inductive loads of attic fans.

Smart relays such as the Sonoff ZBMini, Shelly 1, and some Tuya relays might work depending on the fan load. They are installed at a location where the existing neutral already exists and are also connected to the existing dumb switch.

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There are a few options.

Can you post a picture of the switch? The reason I’m asking is that there are two battery operated switch covers that work with smartthings and just move the existing switch underneath. I have several of these in my own home in places where I didn’t want to change the wiring.

They just work as a basic on/off switch, but it sounds like that may be all you need.

You will hear a sound as the switch is being moved. It’s not as loud as a garbage disposal, but it’s loud enough to startle the cat. But only for the time while the switch is actually moving.

You didn’t say what country you’re in, but because of the neutral issue, I’m going to assume that it’s North America. If not, let us know, as the device selection does vary.

Anyway, these are just a quick and easy solution which will work for some people. :sunglasses:

Here’s the Zigbee model:

And here’s the Z wave one:

These will work fine even though you are operating a fan, because they just physically move the switch. They’re a good choice for a lot of people with various motorized devices that are controlled from a wall switch.

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Thanks all for your fast responses. I really appreciate it. Just after I posted this, I had an interesting discovery in that it seems there are old (definitely not “smart” but dumb analog/mechanical) thermostats already installed adjacent to the attic fans themselves which apparently have been turned off or disabled. I had no idea they were there. It seems if I can get them working it might be my simplest solution. In which case I won’t need to pursue this ‘smart’ path after all. I can’t find any load info on the fan. If the dumb thermostats don’t work I probably will look again at the smart switch that @JDRoberts suggested. Thanks also to @milandjurovic71 , @Paul_Oliver too for your replies

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There is usually a label on the fan casing which gives at least the manufacturer and model number.

Here are some typical label locations:

For attic ventilators, the label is usually on the wiring box so you can see it without having to remove anything.

I’m pretty sure these labels are a UL requirement, they’re definitely a code requirement in many jurisdictions. But they can get worn and grimy over time and be hard to read. :thinking:

The Aqara does work for fans, I use one for my half bath as it has a single no neutral switch to turn on the fan and light. The switch is rated for up to 1/4 hp motor, 600W incandescent, and 200W LED. The switch pairs easily with ST.
I have a double switch for my kitchen Ceiling/Porch Light, another for a couple tube lights in a suspended ceiling and the one in the bathroom. I also use an Aqara with neutral for my freezer room. The No Neutral switches act as end devices and the switch with neutral acts as a repeater, that is why i put one in the freezer room to replace a zwave Eaton switch.

A bathroom exhaust fan typically has a lower load than an attic fan. And older attic fans usually use even higher horsepower motors.

It’s always a good idea to check the specs to be sure there’s a match between the switch and the motor.

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I didn’t find the label, but did see specs for the official replacement motor part, as shown on Amazon: https://www.amazon.com/Broan-Nutone-Motor-S87404000-Gable/dp/B0716CTHZ8
It says the motor is 4.95A. But the user’s manual DOES state a 15A breaker is needed on the circuit. Soooo, is it a mistake to install the Sonoff ZBMini relay, given it is limited to 10A?
My switch is just a regular toggle switch. I’m leaning towards this one you had suggested as the simple option that avoids my concern about the amp load: Amazon.com: Made for Amazon Zigbee Smart Switch, Gen3. Compatible with Echo (4th Gen), Echo Plus (1st & 2nd Gen), Echo Show 10 (2nd & 3rd Gen), Echo Studio, Eero, and Eero 6 Pro : Amazon Devices & Accessories

Yes.

My switch is just a regular toggle switch. I’m leaning towards this one you had suggested as the simple option that avoids my concern about the amp load: Amazon.com: Made for Amazon Zigbee Smart Switch, Gen3. Compatible with Echo (4th Gen), Echo Plus (1st & 2nd Gen), Echo Show 10 (2nd & 3rd Gen), Echo Studio, Eero, and Eero 6 Pro : Amazon Devices & Accessories
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Yeah, those are a good way to handle it because it’s just going to mechanically move the existing switch, you don’t have to worry about matching the load specs. :sunglasses:

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