Best Solution for Double Hung Windows

My house is full of double-hung windows (can be opened from the bottom up or top down). I want to get open/close status on both the top and bottom panes. The way I understand it, there are two options.

  1. Two zwave/zigbee sensors for every window. This gets expensive in both sensors & batteries so I was trying to avoid it.
  2. One zwave sensor with terminal connections and a wired magnetic sensor. I bought an Ecolink door/window sensor and a UXCell magentic sensor to connect to it to make sure everything worked how I wanted it to. And it turns out it doesn’t. In order for the combined sensor to indicate a closed state, it seems to be relying solely on the sensor connected to the terminals. In order to indicate an open state, it’s relying on both sensors reporting open before it registers in SmartThings.

What I want is for SmartThings to report Open when either pane, or both panes, are open. And only report Closed when both panes are closed.

Am I missing something with the Ecolink? I used the default DTH since SmartThings even recognized the brand. But it’s definitely not working how I thought it would.

Assuming I got option 2 working, how have people hidden the wires to the wired sensor? That will be very important for the WAF.

Not sure how far apart the 2 panels but can you put the sensor on one panel and the magnet on the other panel?


A single sensor with an external reed switch will not do what you want. This configuration does not turn it into two separate sensors, it just provides two ways to trigger a single open/closed switch. The result is exactly what you are seeing…if both contacts are open, the sensor will report open, if either contact is closed, the sensor reports closed. This is a limitation of the physical hardware rather than a software interpretation issue.

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This is what I did on two patio slider doors and it worked out just fine. If you have space constraints, the magnet can be removed from the plastic holder and cemented in place…

With the GoControl window/door sensor. @krlaframboise created a DTH for both internal and external sensors to operate separately. I have a couple that use the internal reed for open/closed and external for water sensor.


That DTH will work and so will my regular GoControl Contact Sensor handler, but for double hung windows the external switch usually isn’t necessary.

The GoControl sensor’s magnet works great for my windows, but in order to get it to fit between the panes I had to pry the magnet out of the plastic casing.


I have the same situation. There are a few window sensors that have additional terminals that you can wire contacts to. When doing this, you CAN NOT use the built in contact. You basically buy a couple of contacts and wire them in serial. It takes a little soldering but really anyone can do it.

It won’t tell you which pane is open (top or bottom), just if any of the contacts are broken it’ll trip the sensor.

The old FGK-101 sensor is what I have. I hear there’s a new model but they removed the additional terminals. There are a few others (Schlage and Linear).

I hid my wires with some white trim they sell for speaker wire. Blends in with the window and you never even notice it, especially with curtains.

Here are a few pics so you can envision what I’m describing.

Almost all my window openings are 2 or 3 vertical opening windows next to each other, I have done the same thing. The only issue is it can be tricked, if you close the actual zwave sensor and the magnetic sensor is open it will say it’s closed, in my house usually both (or 3) are open or closed at once, but I did put the actual sensor on the least likely/hardest to get to window and haven’t had any issues.

This is exactly what I did with all my windows, right smack in the middle and it works perfectly.I do know that some windows have the lock in the middle, so just stick it next to the lock “almost” in the middle.

I did something similar on a couple awkward doors where I had minimal space to work with in the door swing direction.

Buy a bunch of these 1/4" D x 1/16" H magnets from Digikey, and try and find somewhere they fit in the weatherstripping between the two panes such that the magnet just slides under when either window moves.

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Thanks for the responses everyone, they’re a great help.

I was misunderstanding the fundamentals of how the ecolink worked with external contacts. I think the ecolink will be heading back to Amazon and I’ll give the GoControl a try with the DTH @krlaframboise wrote.

I’m not sure how I’d be able to use a single sensor to detect when either pane moved? Can anyone post photos of how it’s set up? Any way I think about doing it ends up with a magnet scraped off the surface I attach it to when it slides past the other pane.

Maybe post a picture of your window in question…

I don’t have any in your style, but I do have a ~1/16" gap that the weather stripping slides over at the intersection of my window panes.


Hehe! A double hung window has two sashes! Funny how we speak the “same” language. Friends of ours from the U.K. joke about colloquialisms whenever we visit…

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Funny story, we had your tilt and turn style window at my university on the second floor. Turns out if you try and turn and then tilt, they fall out of the frame and you’re stuck suspiciously holding a really heavy window…


My recommendation was based off of that type of window and the magnet of the GoControl sensor fit between my windows, but I had to remove the magnet from its plastic housing.

If you’re able to mount it like shown in that image then you don’t need the GoControl contact sensors because you should be able to do it with most contact sensors or any strong magnet.

That makes sense now. I’ll have to take a look at our windows to see if that will work.

Thank you all for your suggestions and advice… and the language lesson on how weird the Brits are. :slight_smile: