Smart TRV's - are they worth it to add to a tado smart thermostat and boiler control?

I was looking for local control devices and came across this site which may be useful for those going down the home automation route but wanted local control. It's dated this year so it has relevant information.

https://hometechhacker.com/5-local-control-alternatives-to-popular-smart-home-products/

Peter

Thanks for the link which I’ll study later.

I suspect that most of the smart thermostats on the UK consumer market use internet data for outside temperature.   Here’s a DIY system listed on the BBC that I saw a while ago, costing only £15, I suspect using a raspberry pi pico or similar.
https://www.bbc.co.uk/news/business-62900202

Unfortunately, after checking with Bosch, it looks as if my older condensing combi isn’t compatible with weather compensation anyway.
 

But if you manipulate the thermostat so that it looks like weather compensation then it is weather compensation. I'll give you an example.

I've got a new Vaillant gas boiler with a remote thermostat RT (that transmits and receives both ways) which has a temperature readout on the front. But, the temperature readout on the RT is a lie, an untruth a fabrication. How do it know this? I have an accurate digital thermometer DT next to it and most of the time they read the same until the boiler starts the pump to sample the radiator return water temperature which happens when the room temperature edges down a bit. If it's close to the set point the boiler instructs the RT to suddenly display a lower temperature, significantly lower than the DT next to it. The RT tells the boiler to come on for a short while and after a while it then instructs the RT to display the same temperature as my DT and to switch the boiler off.

The boiler is manipulating the RT display so you can't use it as an actual thermometer. In old school terms it's removing the hysteresis inherent in heating systems by pre-empting a temperature undershoot but manipulates the display to ‘justify’ its actions which is quite unnecessary unless it needs the ‘lower temperature’ to cause the RT to command the boiler on. I'm not complaining, it works extremely well, but I hate displays that lie because ultimately you can't trust what they are saying.

Back to the weather compensation. If you are monitoring the outside conditions, presumably you could add in solar gain (heating) and high winds (cooling) for your particular house, then you could manipulate the temperature set point of your thermostat to cause the boiler to react accordingly. Voilà

But weather compensation on my heat pump alters the flow temperature, it doesn’t switch it on and off…. 

​@juliamc Good point. I've just had a look and it's the same for gas boilers and heat pumps. My Vaillant modulates the water temperature so maybe it's a halfway house mechanism to achieve its high efficiency because that is what weather compensation is about. Probably wouldn't work for an older condensing boiler so well.