Exactly, but they have no incentive to do so. Until one manufacturer decides to try and get market share by producing a better controller, none will try - it suggests market manipulation. 95% of consumers will never know they could be running the HP more efficiently so don’t care especially as HP manufacturers are allowed to report exaggerated efficiency with impunity.
Heat pumps will be forced on consumers.
Many installers are even worse. Throw in a system then walk away.
Just like boilers, at least in the UK. Most ‘condensing’ boilers in the UK are still run at 75C because thats how the installer set it up, and indeed reset them if adjusted by the householder each time the boiler is serviced. At this temperature they almost certainly don’t condense, but the householder doesn’t know any better and it guarantees no callouts (which is the only criterion that matters to most installers).
In addition they are forced to cycle madly because, even though boilers have a turn down ratio n much better than heat pumps, they are hopelessly oversized. Together these add at least 10% to the running cost and significantly reduce the level of comfort.
I guess that this is a legacy of two decades of dirt cheap North Sea gas. Unfortunately its now rapidly running out and the UK is dependent on despot states for a large part of its energy supply.
IMHO there is a very sound argument that the push for renewables is a matter of economic security irrespective of any environmental benefits.
Let’s not go down that rabbit hole.
I’m under the Impression that Aira and octopus are doing something like that? The Aira my neighbor has has only an inside temperature control. Once it was understood that there is nothing else to control it seems to just work.
That rather depends on what its actually doing under the hood. If it is simply applying a thermostatic control rather than actively optimising weather compensation then it is potentially trading efficiency for simplicity. From another fourm that seems almost certainly to be the case with Octopus, Aira is more difficult to tell. We really need these people to come clean on either what they are doing or the out-turn performance before the ‘simple’ approaches can be judged.
Can this be split out into a separate thread? As it’s going off track from Arotherm stuff?
The lack of any detailed local control is extremely concerning for me. Do we know whether this happens locally or cloud-based? It’s 20€ down the drain if your smart bulb manufacturer shuts down the server required to control it. For a heatpump, suddenly having no control over your device in that case is catastrophic. Aira is investor financed and probably not (yet) profitable, so I’d be very careful here. Their #1 target is growth and that’s it. My Vaillant also got installed by Aira before they had their own devices. The install quality is good, but using their default settings of weather compensation I would be burning money. They also did not perform a hydraulic balance as “the TRVs will take care of it”. Surely, the latter issue depends on the local team doing the install, but just because someone offers an all-in-one solution with only a single temperature dial exposed to the customer does not mean that the internals are working as efficiently as possible.
It should, absolutely.
=> Most ‘condensing’ boilers in the UK are still run at 75C because thats how the installer set it up
They are reset to max flow temperature as part of practically all gas checks! So it makes little difference what the original installer did unless weather compensation is fixed.
… or indeed when they are serviced as far as I can tell. Madness!
Different topic …
Anyone have an thoughts on the appropriate diverter valve to use for a Vaillant ASHP and why your choice could invalidate the warranty?
For my install, my installer reused the old Honeywell Diverter valve that’s been on my system for over 15 years when it was a gas boiler. Yesterday I had another supplier looking at my install for a maintenance contract, he mentioned that because I had a Honeywell Diverter valve this would potentially invalidate my Vaillant Aerotherm warranty. He recommended this old Honeywell valve be replaced by ESBE Diverter valve. Two questions:
What’s the reasoning for having an ESBE valve over an Honeywell valve? Is it a flow / pressure issue and does the Honeywell valve impact performance?
Despite digging I can’t find anything in the Vaillant warranty. I assume the system needs to be installed in accordance with the manufactures guidelines, but as a consumer I don’t have access to them to check. Does anyone know if having a Honeywell Valve would invalidate the warranty
Thanks in advance
Ian
I believe that Honeywell valves are/were specified by Vaillant, and are/were supplied with their ‘all-in-one’ installation kits. This may have changed since ours was installed 18 months ago.
I expect the diverted valves maybe technically undersized, so if there is a issue that can be blamed on low flow rates….
Hi Zarch, I think the electrical power in the tables in [Energy Stats UK – 11 Nov 25] may need revised. I am assuming the Valliant COP=(H+E)/E and not COP=H/E, which seems to be the basis of the Tables in the link. I predicted the electrical power as follows…. E=H/(CoP-1).
I enjoy your articles, so keep up the good work.
Regards,
Frank
What’s H and E in your equations?
H=(useful) Heat output power, E=Electrical power.
It looks like the “useful” heat output power is similar to Yield for Valliant.
OK, but then Vaillant also uses COP = H/E. One slightly confusing thing is that they show yield power, which is what’s extracted from the environment. Calling that Y, we have Y = H - E and COP = (Y + E)/E.
Your correct. The article refers to EN14511 COP definition. So per EN14511, it is indeed Heat Output/Electric Input.
Apologies in advance to Zarch, the table matches the EN 14511 terminology.
I now need to re-check the terminology used across Valliant again.
It appears the EN 14511 defines COP= “useful” heat output/ Electrical input.
In Valliant terminology, it is equivalent to COP= Yield output/ Electrical input.
Valliant handover information indicates Valliant COP= total heat output/ electrical input. COP= ( Yield+Electrical)/Electrical.
A little confusing, but it appears some brochures inflate the COP performance on the arotherm+ by a change in the formulae.
I thought so too at first but in the end I was wrong with my interpretation. I also just looked at the Vaillant Website where they state Heat/Electricity as COP. The confusion definitely arises from their use of “Yield” which sometimes gets mistaken for heat. But even in the app they show heat and yield to be two different things. Also pay attention to the fact that cooling COP is different. For cooling, the heat gained from electricity ends up outside the house and is hence not usable.
Hi Andre, thanks for all the constructive help.
I am still confused why Valliant would include the electrical power with the “useful heat” generated for my heating COP. It’s not following EN 14511 and looks like a marketing manipulation to me. After all, the heat pump is outdoors and my house will not benefit from any heat dissipated by the compressor, circulating pump, etc. It looks like a marketing gimmick to improve the COP number. Most homeowners seem to be highly focussed on the COP number, the higher the better, which may explain the motivation behind such a move by Valliant. To be fair to Valliant, maybe other manufacturers play the same game.
The Valliant COP number will always be higher than the industry standard COP with the same data.
Have I missed something obvious?