bigp26

Thanks all - appreciate your comments. My post was all written manually for avoidance of any doubt (the formatting looks a tad weird as I copied and pasted it from my Notes app!)

Hi all, I appreciate you help in advance, and hope this post also helps someone else in the future! I need to make a decision on what heating and hot water system to get installed. All new pipes are being laid, and I will have radiators everywhere (no UFH). My options after quite a bit of research: System boiler: Vaillant ecoTec Plus 630 (30kW) Viessmann Vitodens 100-W B1HF (32kW), Worcester Greenstar 8000+ (30kW). Unvented cylinder: Vaillant UniSTOR 250l, Joule Cyclone Platinum 250l (big price difference). Controller / thermostat: Drayton, Honeywell, Tado X, or the control / thermostat from the brand of the boiler. The other question is of course the setup - I was thinking two zones + TRVs, or if that would be too complex, TRVs or zones (in that priority order - as I feel as though room control would be better?). The trouble I am having is to match everything together in a way that the system runs most efficiently. I like the idea of modulation - but this has led me down a bit of a rabbit hole - my understanding: Viessman works with Opentherm, but may be expensive / difficult to get parts? With Opentherm, it could modulate with Drayton, Honeywell, Tado X which all have smart TRVs. Tado was my preference, but with the recent subscription scandal I think I'd like to go for one of the others which I am less familiar with. Vaillant is eBUS - can't modulate with Drayton, Honeywell, but can with an EU version of Tado v3+ if I want TRVs. I'd rather go with the Tado X + see my comments above. The other option is Vaillant's own controls but they are v. pricey, and their TRVs are discontinued. Worcester 8000+ - it's the loudest, has an aluminium heat exchanger (sub-standard to the stainless steel ones in the options above?) and uses it's own modulation protocol, so only their own controls would do the trick. They do have TRVs but I struggled to find much info / reviews on them. I have also read about Ideal and Baxi boilers but reviews seem to be rather mixed... Thank you!