eCozy Zigbee radiator valve (TRV)

I’ve been looking for a way to integrate radiator thermostats (TRVs) with Smartthings for a while now. Had little luck with this Z-Wave model from Eurotronic. The Danfoss LC13 (also Z-Wave) seems to work, but automation is kind of complicated (you need to use CoRE).

Recently, a Zigbee TRV called eCozy became available in Germany (Europe?). Initial financing took place on Indiegogo, but it’s publicly available for about 70 € now. It uses the ZigBee Home Automation Profile 1.2 (according to the initial spec) and is intended to be used with their own ZigBee base station and smartphone app.

Has anyone tried this or any other ZigBee thermostat that may be available elsewhere? Is there any information concerning support for this product class in SmartThings? In generel, is it easier to get ZigBee stuff working vs. Z-Wave devices?


If it uses the standard ZHA profile, then I think it should be able to integrate with ST. But like the danfoss TRV, someone would have to create a device handler for it. And like the danfoss handler, it’s always possible that there could be issues with getting it to work well. not sure if it’s possible to say categorically that z-wave vs. Zigbee device handlers are easier to write.

This is the first Zigbee TRV I’ve seen.

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From the E cozy website, this is a good sign:

What systems is eCozy compatible with?
eCozy is compatible with ZigBee home automation profile 1.2, and can therefore, opreate with smart home platforms like Qivicon or Almond.
ZigBee Home Automation Profile 1.2

But it would still need a custom device type handler.

If it’s like other TRV systems it’s going to be a combination thermostat and multilevel switch (for the actuator that turns the valve) so it’s probably multiple end points. It would take some work, but it might be done.

But I don’t know of anyone who’s done it already.

They’re about the same, Z wave is probably slightly easier to write. :sunglasses: @tgauchat might have an opinion.

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I’d say “about the same”, unless you already have code for an existing DTH that is a close match; and that has been slightly more likely with Z-Wave in the past…

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Thanks @all for you replies … I suspected as much. Hopefully, Samsung will officially support TRVs sometime soon. I think I read EvoHome integration is on its way. Maybe TRVs will be next.


I’ve developed a DTH for eCozy Thermostats. It works pretty well. I just need to do some finishing touches on it and I’ll post it here in the forum.
Here are the first screenshots.

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Hi Cris,

thanks for sharing your DTH (soon) - refurbished eCozy thermostats are quite cheap right now (39 €), so for people who didn’t go with another system yet, it might be a nice alternative. I bought a Tado kit a a few months ago. While I think tado’s solution is a bit more sophisticated than eCozy, it’s also more expensive.

However, if I understand correctly, one will still need eCozy’s Central Unit in order to do firmware updates, even though the TRVs work directly with SmartThinks. Correct?


Hi Jan,
As of today I think the CU is the only way to update firmware. Although ST also has the ability to update the firmware of ZigBee devices. So, whenever a new firmware becomes available I will look into the possibility of doing it via the ST hub. I do have an eCozy CU just in case, but currently it is not in use since the thermostats work well with ST.
Other than that I plan on implementing most features from the original CU into the ST device handler. The next thing is the weekly schedule, which is a standard ZigBee feature. And since the open window detection of the eCozy is not sensitive enough (at least in my house it only kicks in with fully open windows and the wind blowing :slight_smile: ) I am implementing the ability to associate a contact sensor with a thermostat to do the same when the sensor opens. This is something the eCozy CU can‘t accomplish since it is not aware of the other smarthome devices.
BTW: I don‘t think the 39€ units are refurbished. I also only paid 39€ and got brand new thermostats.

I just wanted to link this thread to my device handler that can add eCozy Thermostats to ST. I will write a SmartApp as well that can add some of the functionality that the Central Unit from eCozy gives you, like creating heating schedules and grouping devices in rooms etc. But, for now I have the device handler finished at least.

I checked about the firmware update capability. According to eCozy, even their CU today does not do OTA updates of their thermostats. And from a discussion with SmartThings I was informed that the ST OTA updates for ZigBee devices is only supported with those devices that they include the firmware within the ST Hub Firmware. So that limits the amount of devices that will ever get OTA updates through the ST OTA Update feature. Basically only the ST devices and a very select few other devices will ever be supported.
With that said, firmware updates is not a limiting factor compared to using the eCozy CU. At least for now.

Hi Chris,
wow, that’s interesting. Every ZigBee system I know (SmartThings, Hue, Lightify) can do OTA firmware updates - for their own stuff only, of course. Those eCozy guys must be pretty confident there are no bugs in their firmware. Just out of interest: is there a USB port on the thermostats that would make it possible to do updates from a computer (should the need arise)?

Actually they have had bugs in the past and I have a few thermostats with old firmware with these bugs as well. Unfortunately, I have to send in my thermostats to get them updated. :frowning:
I hope they do allow OTA updates soon.

I suppose there is some port (JTAG?) behind the casing to do firmware updates, but it is not directly accessible.

@ckpt-martin That’s unfortunate and also kind of short-sighted not to implement OTA updates in a product where the firmware is almost certainly going to have bugs.

As I wrote before, I’m currently using tado’s system, and while I like the product in general, they seem to have issues with quality assurance. I bought five radiator thermostats, two of which have already failed: their weakness seems to be getting the valve to close reliably.

At three occurences, one of my radiators would burn up while the thermostat reported the valve was closed. At first I suspected a calibration issue, but it turned out to be faulty hardware. Luckily, this only happened when I was home - however, my confidence in their product is really declining. Who is going to pay for three weeks of unnecessary heating if this happens when I’m on vacation?

May I ask how many eCozy TRVs you have and if they’ve been reliable for you?

I currently have 7 installed and they have been reliable. I have one that is broken and needs to be replaced.
I did have to calibrate the temperature measurements for a few days by using a separate thermometer in the same room and adjusting the thermostat temperature to get as close to the thermometer as possible over a period of time. You can adjust the temperature from -2.5 to +2.5 degrees.
I still need to code a smart app to allow me to load temperature schedules. And since I have some rooms with two thermostats I would like to group them.

The only thing I don‘t really like is that they decided to only display the „set“ temperature on the device itself, using different colors to indicate if the thermostat needs to heat or cool down to reach that set temperature. That is a little confusing for wifey. Luckily I display both the current and the set temperature in the ST device handler. I would like the thermostat to show both as well, but it doesn‘t. You can only change the set temperature on the thermostat to see what the current temperature is by setting it until it turns green (current temperature = set temperature). But that is not practical in my opinion.

Since eCozy have had some issues with early firmware I would recommend purchasing from them directly to make sure you get units with the most current firmware. I originally purchased over amazon and all of them had faulty firmware that were off by 4 degrees and also drained batteries within two weeks. ECozy replaced them for me and I haven‘t had the issues with these. Only one was broken from the beginning (constantly flashes the open window symbol) and they are going to replace it.

Thanks for your work @ckpt-martin!

I was wondering if the eCozy valves can be used as temperature sensors for other automation stuff in the home?

My idea is to get a smart thermostat (Nest, EcoBee etc) and some eCozy valves. Then I’d like to set everything up so that the thermostat will turn on if at least one of the eCozy-monitored rooms report a too low temperature.

At this point I’ll have the home heating system up, and only the rooms that need to be heated up will have the heaters open.

Do you think this is possible? I don’t mind to write some software if needed.


Well, I‘m not sure why you would need an Ecobee etc. for this, because that is what the TRV does itself. It measures temperature and heats just that room as needed.
But, to answer your question, I suppose you can do what you are looking for because the TRVs do report the currently measured temperature and you could do automations based on those temperatures.
But, the TRV is already set up to do this on its own by way of you setting the target temperature for the room on the TRV and it will open and closed the valve to keep that temperature as close as possible.

So would you leave the boiler always on? I think that even if all the heaters are off, the boiler will consume a significant quantity of energy just to stay on, don’t you think?

The eCozy opens and closes the valve. So when the valve is closed there is no energy produced at the radiator. But, I think you mean at the central heater where the water is heating in the first place. I‘m not sure how yours works, but mine is already quite efficient. So, adding the eCozy just dynamically opens and closes the valves at the radiators for me instead of having to do it manually. In that sense it is still an energy saver since it will close the valve anytime the target temperature has been reached where it would have been open all the time previously if I didn‘t manually close it.

Hmm, I think @FezVrasta might be right. Your boiler is constantly running? Shouldn’t it heat when a thermostat calls for it? It’s the boiler that expends energy to heat water, not the radiator in the room. There’s no reason why the boiler should constantly be churning out more hot water (or steam, I actually have a steam boiler).

I guess TRVs could make your boiler heating more efficient by diverting heated water from rooms that don’t need to be warmed up, thus decreasing the total amount of water that needs to be heated to get the occupied rooms to the right temperature.

But the boiler needs to be told to shut off otherwise its heating more water for no reason…

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