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Z-Wave StellaZ Radiator Thermostat

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StellaZ is a Z-Wave wireless Thermostat Valve capable of controlling heating, air ventilation and climate control units. The thermostat valve includes temperature sensor, control and actuator functions in a single device allowing stand alone control of a room's heating/ventilation.

The StellaZ can run in four different operation modes (Frost, Energy Saving, Comfort, Direct Control) and reports the room temperature to the Z-Wave network.

  • Frost Protection: The room's temperature will be regulated to about 6 °C.
  • Comfort: The temperature will be regulated to a comfortable level - factory default is 22 °C
  • Energy Saving: The temperature will be regulated to a energy saving level - factory default is 18 °C
  • Direct Valve Control: This mode allows the direct control of the valve as percentage value
  • Note: Comfort and Energy Saving modes can have their setpoint changed by the Z-Wave controller

The thermostat valve also includes an 'Open Window' function that automatically closes the valve when a window or outside door is opened.


Technical Details

  • Technology: Z-Wave (868.42MHz)
  • Thermostat temperature range: 0 - 50°C
  • Operation Modes: Frost, Comfort, Energy Saving and Direct Vale Control
  • Control: The units Setpoint can be changed by the Z-Wave controller
  • Buttons: Include and Exclude
  • Adapters: Supplied with M30 x 1.5(K) valve adapter
  • Power: 2x AA batteries (1-year lifespan)
  • Dimensions (LxWxH): 65 x65 48mm
4.30 / 5.0
10 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Moved from LightWaveRF valves to the Stella and what a difference. These valves make very little noise and look smart. I now have one on all 16 or my radiators..
20 Dec 2016
1 year ago
Good when they work
These units pick a signal well generally. However they don't seem to last all that long and are not very robust. The can get knocked off the radiator quite easily if used in a public hall for example. I have had to replace several and replace the collars that connect them to the radiator on others, because the thread has not held - unit drops off when it closes! Will keep looking for a more robust option!
22 Oct 2016
1 year ago
Good Product and Service
I'm pleased with the performance of the eight Stella-Z trv's installed on my Vera Edge system. I've also received good support from Vesternet with one unit that has needed attention. I also like that the device reports its temperature to the system web page and mobile app. It's also shorter (and fatter) than some alternatives. This enables a Stella-Z to be fitted where the alternative would be too long to fit. This was a major consideration in my original choice, given the proximity of a radiator to an adjacent wall. I've also had superb customer support from the German wholesaler, Eurotronic, with regard to one Stella Z that I managed to lose a moving part from. I've no experience of other Z-Wave trv's.
20 Jun 2016
1 year ago
No the prettiest. Not the quietest. Not the easiest to set up. Like batteries. But… it works. Had a few fail on me, which Vesternet replaced and they appear stable now. Second winter using StellaZs and once everything is configured in your controller they work just fine.
22 Apr 2016
3 years ago
Multiroom Rad stats
Have a couple of these now. The vera lite WILL NOT allow the function of direct control so you can not say close/open/50% etc. BUT if you want to say have the rad off in the bedroom in the morning, or only at 18 deg then this will work fine. Took a few attempts to get it to work but worth the time.
25 Feb 2015
Works with Domoticz / Aeon Zstick but check for a good fit!
Valve works well with Domoticz and Raspberry PI using Aeon Labs Zstick 2. Latest Domoticz versions allow for mode changing (Frost / Economy / Comfort / Direct). If the valve apparently fails to respond to set point changes, check that it is not in Frost mode by mistake. This valve reports temperature back to the controller - very valuable indeed! Be sure to check that the calibration function works when you fit the unit to the valve body - listen for the radiator flow to be cut off entirely! If this does not happen (because the adapter is loose or wrongly fitted) then the thermostat cannot control correctly. Case is a bit flimsy, but adequate. This thermostat allows one to make a zoned heating system without plumbing!
17 Nov 2014
Easy to set up and responds well to commands
The unit was easy to fit and set up, and is much more responsive than another type of valve I tried. My only concern so far is that I've had to replace a set of batteries after less than three weeks. I'm hoping that was a one-off, but we'll see...
12 Feb 2014
as billed
working well with RaZberry module for raspberry pi.
29 Jan 2014
Pretty damn good...
The only issue is that the valve itself suffers from a little heating from the radiator itself, leading to slight temperature errors. I guess this would be an issue for ANY thermostat connected to the radiator itself. Works find with Domoticz and RaZberry on Rasperry Pi.
23 Jan 2014
Far better than Danfoss
Easy to install, works well with Razpberry pi and Razbian Z-Wave, battery life is far greater than the Danfoss Living Connect. Excellent.
18 Dec 2013
Browse 8 questions Browse 8 questions and 15 answers
Why did you choose this?
Vesternet Store
Replaced Danfoss with these and its a much better product. Quite large and does not fit in every location. The current temperature reporting works well.
esilvester 16 Nov 2016
Replaced Danfoss with these and its a much better product. Quite large and does not fit in every location. The current temperature reporting works well.
esilvester 16 Nov 2016
Have 4 already and please with performance so far.
Dan L. 15 Apr 2016
Have 4 already and please with performance so far.
Dan L. 15 Apr 2016
Excellent Chose these to allow me to control each rooms temperature independently. Not easy to setup with Vera Lite but worth the effort. Would highly recommend.
ian m. 16 Apr 2016
Excellent Chose these to allow me to control each rooms temperature independently. Not easy to setup with Vera Lite but worth the effort. Would highly recommend.
ian m. 16 Apr 2016
Hi - via Z wave, can you use a temperature sensor somewhere in the room as the control input to this, rather than it's onboard temp sensor?
James H. 28 Nov 2016
How much noise do these make? One review says "Not the quietest" - I've never heard noise from a TRV, and I do not want a buzzing sound in the bedroom when trying to sleep!
Brian G. 21 Nov 2016
BEST ANSWER: Mine is near silent. Thing to remember is they use small electric motors to open and close the valve so there is bound to be some noise. I have another valve which is electronic but not wirelessly controlled and is considerably noisier in operation.
When I change the batteries the devices always stop working. The last time I tried I ended up giving the device a new network id. There must be an easier way (6 valves, zstick v2, pi3, Domoticz(latest beta) 2 years)?
Guest Visitor 15 Nov 2016
BEST ANSWER: For support and help with products purchased from Vesternet it's best to raise a Technical Support request using one of the following methods: 1) Click on the "Support" link at the top of any page of the Vesternet web site 2) Complete the form at 3) Email One of our Technical Support team members will be glad to assist you further!
Stella Z - What is the best valve to use with Stella-Z (Honeywell V120-15A TRV Body Only (15mm Angled))?
chris P. 19 Sep 2016
BEST ANSWER: You can use it with any standard valve fitting so long as it is M30 x 1.5 - this is probably the most common type used in the UK and other countries, so easily found from companies like Honeywell and Danfoss...
Hi there, does this work with the Fibaro HC2 controller?
Andy 10 Jun 2015
BEST ANSWER: Hi. Currently StellaZ does not work in HC2. We have tested it in v3.xx and the current versions of v4.4x, it is not possible to set the StellaZ setpoint from HC2, and is therefore incompatible. We show this in our Z-Wave Compatibility Guide -
How can we control these from Vera Lite? There's no easy way to control them, They constantly fail to update set points. and whilst there are several "Workarounds" on the forums, theres nothing that just works. Anyone got one working correctly? Thanks.
Andrew 28 Jan 2015
BEST ANSWER: They work fine for me, I have been using them for over a year. Make sure that the wakeuptime is not to long, I have mine set to 240 of 480 (have to be multiples of 4 minutes). unless it is for a room that you don't use very often. The Vera interface might say that there is a failure to communicate, but I think that is because vera doesn't handle wakeup times very well. As soon as the device wakes up, the SetpointTarget argument is passed to the unit and the vera interface recognises that the communication has been re-established. This might take up to the wakeup interval, which out of the box is 28 minutes. If you change the wakeup interval, I think it works better if you press the reconfigure button as well, and press the button on the Stella for a number of seconds until the red light starts flashing. Hope it works, any more questions I'll try to help, or check the micasaverde forums, I found them very helpful. Kind regards, Hans
I'm trying to fit one of these to a radiator at the moment. The radiator valve has GB 15 on it. I'm a bit confused how to connect it though as it seems slightly too big
Tony 15 Jul 2014
BEST ANSWER: Hi Tony, It's best to send us a technical support request, that way our technical team can quickly help you resolve this issue. We don't have your contact information on this review, so can you send a request to

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