Central Heating System Change - - - - OpenTherm or Weather Compensation - - - - Advice please.

My current setup is a Viessmann 050-W Combi boiler with a tado° Extension Kit (+ Hot Water control) connected in OpenTherm and 10 SRT's plus 1 Wireless Thermostat and 1 Wireless Temperature Sensor. I have 5 of the SRT's without a Zone Controller (INDEPENDENT) I have lowered the Max Flow temperature to 65° C from the tado° default setting of 80°C

I have had my tado° for over 2 years now, and I am frankly getting annoyed with the number of times that I have had to "adjust" my setup to try to achieve a "happy medium" between comfort and efficiency of operation........not to mention the annoyance that I feel every time I discover that a tado° feature either doesn't work at all or simply doesn't work as indicated by tado° (sales gimmicks)

So I have decided that once this current Heating Season is over I need to make a decision regarding my CH system.

I have noted that my current Viessmann boiler can be set up with Weather Compensation. However I'm not sure if I could/should retain any of my current tado° devices. There have been a couple of comments in other threads regarding using Weather Compensation.........however I need to know more information before I decide on a course of action.

I have already "heavily invested" in my tado° system, and don't want to " throw good money after bad" as the saying goes......but I am willing to cut my losses and move on. I could just simply wait for the (supposedly expected) next generation of tado° devices and "hope" that tado° will address all the many well known issues that their current range of devices have.........but even if tado° does manage to produce a great new product range.......what about the customer support.......??🤔 That is a complete unknown !!!

So can anyone provide me with a little guidance on what you think I should take into consideration before I tear it all down and start again........ps......I'm a Viessmann fan.


  • WC and relay. Keep all your tado gear if it's not driving you nuts. Don't micro-zone.

    If you have advanced weather comp with parallel shifting, it'll be like getting a completely new system. Even if it's basic weather comp, it'll still perform better than OT.

    It'll take some trial and error to find the right curve. If on basic WC, don't set back too aggressively (at night or away).

    Assuming you need to get the WC sensor, even with a pro fitting (maybe at the same time as the service), it'll probably cost less than a decent replacement room stat.

    Good info on heatgeek.com, as you'll probably already know.

  • I’m sure you’ve got your Tado system as efficient as it could be by now. Really depends whether you want the possible increased efficiencies of weather comp or whether you’re happy to leave the system as is. If you’re getting regular drop outs I would consider weather compensation.
  • @johnnyp78

    Not having any drop out issues if I'm honest.......👍

    It's just that I seem to have to keep making changes to all/ most room temps on a regular basis to try to achieve stability. I'm on tado° too often for my idea of an "automated" system.

    I would really like to get opinions regarding the operation of a combi boiler using Weather Compensation...........so I'll wait and see who offers any information.

  • @GrayDav4276 - WC operates the same on combi as system save you don’t need DHW priority.
  • I have been using weather compensation for over 10 years in a home-brew control system and the effect on comfort (and cost) is magic. I use tado and older Elv/Conrad TRVs but they don't control the boiler temperature. They are perfectly good at controlling the rooms, and providing a signal that calls for heat. There is an over-riding programmer in charge. The wiring is a bit complicated to get the logic right but the effect is max comfort at min cost.

  • Thank you......anyone else got details of using WC......specifically with a Viessmann boiler would be good.

  • No-one else got any comments.
  • Sounds like you need to take a fresh look. Have a read of sunk cost fallacy and watch some HeatGeek and Urban Plumbers.

    Once you’ve got an idea of how to better set up the system and control it, then going WC makes sense to me. But it’s only as part of the holistic view of the heating system and home, plus your comfort/efficiency needs.

  • GrayDav4276
    GrayDav4276 ✭✭✭
    edited December 2022

    Hi @Montage

    I've had my tado° system for over two years and have tried many various combinations of setups in that time. I've also done an awful lot of investigative reading and viewing of many articles and videos........hence my request for anyone with information on whether they can advise me regarding WC on a Combi boiler system. Any information will be gratefully "absorbed" to allow me to make an informed decision regarding the (possible) benefits of radically changing my current system.

    I'm about to make one more (last) system change to see if I can achieve the balance (that I am after) between comfort and efficiency using the tado° devices that I have already spent a small fortune on. [ Shout out to @eezytiger ]

    I will decide by the end of the current heating period (Mar '23) which direction my CH & DHW system will be using going forward......if I'm happy with my current tado° setup, then that'll be fine, but if I decide to go with a Combi boiler with WC......then that will also be fine.