My 14-year-old Mains Eco 30 combi has died (£1k repair quote), so replacing it. 2 bed + box room terrace in UK, single heating zone with manual TRVs. Long-term home.
Got three quotes, all 30kW combis:
1. Vaillant EcoFit Pure 30kW - £2,800inc VAT (10yr parts & labour)
2. Baxi 800 30kW - £2,950 inc VAT (10yr manufacturer warranty)
3. Ideal Logic 2 30kW - £2,400 inc VAT (10yr warranty) + £80 for outdoor OpenTherm sensor
OpenTherm questions
One of the plumbers was quite blunt - said OpenTherm is “a waste of time” and he wouldn’t fit it in his own house. This has put me off a bit, but wanted to get the HA community’s take.
• Is OpenTherm actually worth having for real-world efficiency gains?
• Does it make a noticeable difference to running costs or boiler longevity?
• Or is it more about smoother temperature control with marginal savings?
I’ve done a fair bit of reading and I’m genuinely not sure if it’s marketing hype or genuinely beneficial for day-to-day operation.
Tado X rant (sorry):
Currently running a Tado X wireless thermostat and honestly feeling a bit stung by it:
• No working Home Assistant integration for 2+ months now
• The hub won’t integrate into Matter at all, despite me having a Smlight SLZB06-MR1
• Now reading they’re locking smart TRV features behind a yearly subscription in their app
So I’ve deliberately not invested in any Tado X TRVs and I’m stuck with just the basic wireless stat. Wish I’d researched this more before buying into their ecosystem.
The actual question:
Which boiler would you go for? And should I bother with OpenTherm, or save the £80 and potential headaches?
Eventually want to rip out Tado entirely and move to a proper HA-native setup (thinking Shelly TRVs or similar), but that’s a future project once the boiler’s sorted.
Any advice appreciated - don’t want to make another costly mistake!
Installing heating is a profession of its own. I would not trust a plumber to give great advice on it. It might just be he lacks the knowledge and does not want to admit to that. OpenTherm is most certainly better than (modulated) on/off switching. It will both save money and be better for the equipment. Heating without OpenTherm is like trying to drive 30Mph when you can only go full throttle or slam the brakes.
As for Tado X I understand your frustration and Tado may no longer be a brand I’d recommend. Also because their tendency to be cloud dependent. I own Tado V3 with smart features and no rate limit without paying subscription so I’m lucky. You should be able to add the TVR’s as Matter devices though that way it won’t support all features of the Tado integration. You might want to look out for another brand, preferrably not Matter or you’ll likely still be limited. The technology is still in its infancy.
But as for switching to full HA operated I would advise against it for multiple reasons. First of all you won’t be able to get nearly as good a heating system as with a dedicated zone based thermostat system. Things like operating the pump at the right times, preventing overshoot, smart start etc. are difficult if not impossible to get right from HA. HA is not designed for that. But also you would not want to sit in the cold when HA is somehow down.
Get a good zone based thermostat from a reputable brand and use HA to step in where the thermostat is lacking in smartness. For instance, in my home Tado controls the temperature in my home as if everyone is home. HA steps in for exception handling. For instance when people leave to shut of their room(s), when windows open, when people start up the shower to crank up the bathroom heat a little. Stuff like that. If HA would go down, the heating can still operate like a normal home.
For an explntion of the benefits of OpenTherm, this is a quite good expantion: