Radiator valve with percentage rather than temperature

We do have a floor heating with thermostats in each room turning each cycle on an off.

In the distribution box there is a valve (similar to the one on a radiator) to change the temperature sent into the heating pipes. Currently there is an old-school valve which works okay, but allows only static temp setting.

The idea was to replace it with a smart one - while the issue here is that all “smart” thermostats are a bit too smart for this purpose since they allow only an air temperature to be set rather than setting a percentage opening. (just tested with the fibaro, but didn’t do the trick)

Any ideas on smart radiator thermostats (either z-wave or zigbee) which either don’t have an actual thermostat or allow disabling it in favor of percentage opening? (or 3-5 settings 1-2-3-4-5 like the existing one)


It is not zigbee nor z-wave but wifi: The Shelly TRVs have a valve-only mode:

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Thanks, sounds good - while I would prefer a zwave/zigbee solution this looks like a reasonable alternative - I will check it out!

The alternative way would be to have a temperature sensor on the pipe and then use automations to close and open a normal TRV by setting radical temperatures, like 0.5C or 1.0C above or 3.0C below the target.
These target temperatures would then open or close the valve and since it is now smart, then around 30s later you will be able to update it again to keep the temperature at the target.

The radical target value above is small because the valve will have to actively heat to reach it.
The radical target value below is big to avoid the valve thinking it can handle the cooling by natural dissipation from the room.

That was my original idea for the Fibaro using a the external Fibaro sensor, however the maximum temperature setting of 30° was a blocker since the water temperature may be up to 55° if the valve is fully open.

If you measure the temperature with a smart thermometer connected to HA, then you can just set the TRV to a value that will fully open the valve anyway, since the temperature it measure will probably not be the 55C, but the air temperature around it.

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indeed, that would be the fallback if I don’t find another solution - I just want to prevent the constant opening and closing which may be caused by this kind of setup, also the air temp around the valve may also be influenced by the pipes for warm water generator and the pumps

There are some Zigbee TRV that have a valve opening percentage function, but it’s only accessible using Zigbee2MQTT. It’s been a couple of years since I looked into this tho, so I can’t recall any specific model at this moment.