Due to unforeseen events, my DIY Heating System had been paused. I was about to install smart TRVs in each room… A long story short, I’m in a new place, hoping to buy a house soon and resume the project. It’s far enough from the heating season on this side of the planet to plot and plan heating solutions ahead and ITEAD thinks they have something to help you out. An inexpensive, smart thermostatic radiator valve. Is Sonoff TRV any good?
I got mine a month early, so I could test it with eWeLink, submit the feedback and perhaps try things out with my custom Sonoff ZigBee Dongle. After all, a lot of you will be interested in the ZigBee aspect of the Sonoff TRV. It’s not my first TRV. I ended up with 11 TRVs from Moes (I made the purchase before Shelly and Aqara released theirs). I’m looking at Sonoff TRV and I wonder if I made a good decision.
Sonoff TRV is white and seems featureless. At first glance, the only interactive element is a very smooth rotary encoder that doubles as a push button. The box comes with 6 adapters to increase compatibility with the most popular radiator valve fittings. As Sonoff TRV works with ZigBee 3.0, you will need a hub. ITEAD advised me Sonoff ZB Bridge Pro and they sent me one, as I flashed mine with Tasmota a long time ago. I was also assured that Sonoff TRV will be supported by iHost – so if you have one, or have been planning to buy one – now it’s your time.
Three AA batteries power the thermostat and offer a lifespan that should last a season. Slide out the cover to reveal the battery compartment, two-digit display and a reset button. The 8 segment display is actually castellated and looks really nice once the cover is put back on. As the display only offers 2 symbols, most interactions will be done via the eWeLink App. The thermostat will indicate it’s “on” with a small fire icon.
In action, the Sonoff TRV is very quiet, and I had to keep my hand on it to check if the valve was actually being actuated. Just note that my test valve is brand new and your circumstances may be different.
How many do you need?
Thankfully, the Sonoff TRV isn’t expensive compared to other TRVs out there. At $26.90 it’s a steal especially if you order enough to cover your shipping costs. At most, you need enough TRVs to cover the number of radiators -1. It’s a good idea to leave one open, to keep the boiler from overheating, especially on older systems.
You can start with a single TRV and expand from there. It may seem counterintuitive, but you should “smart up” radiators in the room you use the least. It’s all about removing the heat from places that are not in use often while keeping other rooms pleasantly hot.
At the time of the writing, the iHost was not supported, but ITEAD staff assured me that soon enough (November), you’ll be able to add your Sonoff TRV there. Without this option, I linked my Sonoff ZB Bridge Pro again and paired the unit to the ZigBee bridge. It feels very responsive with commands being executed within a second or so, the same goes for the updates in the app.
The user interface in eWeLink is very pleasant. The clean temperature controls are featured on the main card for quick adjustments, while advanced scheduling is possible in the Smart Schedule tab. Schedules provide you with an easy-to-read bar interface showing the time intervals where TRV is on, but for information about the temperature set for this period, you have to refer to the list below. It’s a shame as it would be nice to see the temps at a glance too, each period changes into a more intense colour the higher the thermostat preset is. Hidden in the corner, the export option allows you to quickly replicate complex schedules between multiple TRVs – nice!
Extra options include a child lock, Open Window Detection (It’s nice to see a note explaining conditions that will activate this option) and Frost protection. It took a long (20min+) firmware update (1.1.1) to enable temperature calibration in settings, so if you don’t see it at first, make sure to update your Sonoff TRV. There is no option for adding an external temperature sensor. It comes as a surprise, especially since Sonoff recently released new ZigBee Sensors.
eWeLink also provides you with a statistic panel that will record activation times and recorded temperatures. As the intervals are set to hourly instalments, these won’t be as detailed as many of us would like. It’s a shame that the device card doesn’t feature the current temperature settings or the temperature reported by the internal sensor.
Amazon Echo ZigBee hub?
I was losing hope, as the pairing process took some time, but Sonoff TRV paired with my Amazon Echo Hub directly. The interface is… barebone, but that’s Alexa’s fault. The only options available to me were the temperature readout, thermostat temperature and the current mode.
Granted, I added it as a Thermostat, not a TRV but that was the only option in my Amazon Echo device. It will work, but not every option is exposed.
About that… My Tuya hub is no more (I left it behind while moving), so I can’t test it right now, but I suspect it will work just fine considering the fact, that the Sonoff TRV paired with my Amazon Echo.
NodeRED and ZigBee2MQTT next
My next step is to work with ZigBee2MQTT and create (or adopt) a custom converter to support Sonoff TRV. I’m especially keen to find out if this TRV supports direct commands ON|OFF just like Aqara TRV. It would help a lot in developing my custom heating solution.
Shop with Sonoff
Take a look at the ZigBee and WiFi range of the devices compatible with eWeLink:
You’ll have to tune in next time to learn more about Sonoff TRV and custom coordinator use. I hope that this article left you hopeful about getting inexpensive TRVs that would help you lower the heating bill. After all, the winter is coming, and soon it will be too late to play with heating systems. Until then, let me know what you think about Sonoff TRV in this Reddit thread.
🆓📈 – See the transparency note for details.