HomeHome AutomationShelly TRV - WiFi valve that lasts years?

Shelly TRV – WiFi valve that lasts years?

Forgive my Bulgarian accent

All thermostatic radiator valves I have seen so far were either battery-powered and utilising ZigBee or required a wire to bring the power in and keep the power-hungry WiFi operational. It looks like Shelly has solved that. After Shelly Motion got treated to a beefy battery and low-power WiFi. it’s time for a Shelly TRV to hit the consumer market. The timing couldn’t be more unfortunate for me, as I just acquired 11 ZigBee thermostats for my house!

Heating, but smarter

Shelly TRV
Shelly TRV

Clearly, releasing a new line of products: Shelly Plus wasn’t enough, Shelly decided to surprise me with yet another cool product: a connected TRV (thermostatic radiator valve) to try with my home automation system. Smart TRV is the next best thing if you want to save on energy bills as they let you reduce the temperature or isolate completely less frequently used rooms without affecting the heating system. Intelligent use of the TRVs can also boost how quickly other rooms heat up as less energy is spent on distributing the heat evenly to each room. Considering what’s going on with electricity and gas prices in the UK, this is going to be a hot topic very soon!

Shelly TRV – close up

Shelly TRV and adapters
Shelly TRV and adapters

Shelly TRV is slightly bigger than I was expecting, but its sleek white design and rectangular shape make sure that the device will blend in next to your radiator. It latches to the existing radiator valve and directs the hot water flow to it as needed. While compatible with some valves directly (and through the included attachments), check this list to see if you need to get an adapter for your valves.

The control interface is basic: two buttons on the side for basic adjustment and a very limiting 2 digit eight segment display to show the basic info on button press indicates that Shelly TRV is all about smart control. It’s clear that you won’t be adjusting, or setting this from the unit. The display and controls are spartan and are made to be only used in emergencies. At the bottom of the TRV, you will find a USB-C port to charge up a non-removal 6500mAh battery.

Shelly claims up to 2 years of use on a single charge. Since it’s a new product, I can’t comment on that, but if a single charge carries me through a heating season I’d be more than content. Three weeks in with the TRV mindlessly attached to a test valve and self-adjusting according to my office temperature and the battery went down from 100% to 99% – that’s very promising. Power consumption will depend on various factors like the frequency of use, but also on how smoothly your valve is operating. It’s as hassle-free as it can get, connect a power bank overnight and your device is ready for the next year of use.

What sets Shelly TRV apart is the WiFi interface and no need for a dedicated hub, which wasn’t the case with Moes TRVs I purchased earlier this year. In fact, you could ditch the Shelly Cloud app altogether as a built-in web interface will serve you just as well – if you like to keep things local.

Shelly TRV – compatible with all.

Unlike most ecosystems, Shelly strives to bring the ultimate compatibility to all platforms. They showcased this well with Shelly Plus, so I’m expecting nothing less from Shelly TRV. While Shelly Cloud comes at standard, the inclusion of mobile apps, smart voice assistants, MQTT, Webhooks, and LAN modes assures support with other systems. It’s something I really like Shelly for and recommend others to pay closer attention to how their ecosystem is evolving.

Support for external sensors

Shelly TRV & Shelly T&H sensor
Shelly TRV & Shelly T&H sensor

As you would expect, placing a temperature sensor next to a hot radiator is a bad idea. I resolve this with a self-calibrating script for ZigBee TRV I purchased, but shelly comes with support for external sensors and calibration by default. Have they read my article about TRV calibration? Whoever gave them the idea, deserves a medal.

Shelly TRV settings
Shelly TRV allows temp input via REST

Instead of keeping this feature locked to the ecosystem and driving extra sales of Shelly T&H sensors, they opened up any sensor that can supply data over the internet. It’s genuinely nice to see this done in such an open way.

Somewhat confusing app

While the Shelly Cloud app does a great job with relays and all other Shelly devices, the interface for the TRV is somehow confusing. At the first glance, the UI displays the current temperature, valve approx position and quick ways to enable/disable it. But the actual thermal aspects of the thermostatic valve are hidden. In Shelly TRV settings, you can toggle between temp-based controls and relay position controls. While most of us will pick the temperature-based controls, I appreciate having the option.

To drive the temperature profiles ShellyTRV uses time-based schedules. These are pre-named based on random rooms names not even present in my home which confused me even further. A Shelly TRV located in the office had a list of schedule names (none, Livingroom, Livingroom1, Bedroom). It took me a while to figure out that these are just custom names for whatever your planned schedule for that thermostat should be.

To fully take advantage of the Shelly TRV you will need to add a dedicated thermostat device to your ecosystem. This could be a Shelly relay connected to your boiler with a Shelly Temperature sensor. It’s a nice, easy and relatively inexpensive way of adding Nest alike thermostat to your home. It’s precisely what I’ve done 4 years ago with my 30-year-old thermostat. I guess they do read my blog after all!

Shelly TRV can link up to MQTT (automatic updates every hour+ state changes), issue REST requests on state changes (and limit these to a specific time) as well as work in LAN only. It can work over WiFi (2.4GHz) and create your own AP access point and let you use a web interface instead of the app. I had issues applying MQTT settings from the app (reported) but using the web interface allowed me to set Shelly TRV with MQTT without any problems.

I played with MQTT and NodeRED for a bit, and I was able to get information out of the TRV, but while the device is in pre-order and the API documentation is lacking, I will hold off with direct control until more info is available. This would make a great follow-up to this article!

In use

The state of the pandemic, winter and constant lack of time delay the day I can install TRVs in my home. As none of my radiator valves is compatible right now, I have to book a plumber for a day, bleed the system and re-weld new valves across 11 radiators. It’s a big job, and until then, all my opinions about Shelly TRV are purely speculative.

Get Shelly

Check out other devices from the Shelly series to build your ultimate DIY automation:

Final thoughts

Shelly TRV is available for pre-order only at the time of the writing at €59.90 with subsequent discounts for buying Shelly TRVs in packs. Buying it all at once can be expensive, but as winter ends soon, buying 1-2 Shelly TRV a month would be the most wallet-friendly way of getting your house ready for the next winter. There is enough tech inside to feel that the price is justified, but considering that the average house will require 5-6 of them, it’s considerable spending, especially if one is as unlucky as me and valve replacement is needed. With massive energy hikes coming, we may see more people investing in TRVs to bring the price down. Let me know what do you think about Shelly TRV in this Reddit thread.

🆓📈 – See the transparency note for details.


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