We had two ASHPs installed, a Stiebel Eltron one for our house and a small Grant one for our office building. The installer was used to putting in Grant ones, but to his credit, said that he thought our house wouldn't be suitable for a single Grant ASHP. He was honest and said he hadn't installed a Stiebel Elton ASHP before, but had just been on the training for it and he thought a single one of those would be more suitable than two Grant units.

The Grant one was installed fine, and he said he would come back when it is really cold and set up weather compensation properly and improve flow rates. I can't get my head around the controller though, so not sure what temperature it is currently operating at!

However, the Stiebel Eltron was a bit of a nightmare and the unit wasn't working properly and he kept coming back to fix it but it still wasn't working properly. In the end, after he had spoken to another Stiebel Eltron installer he found via LinkedIn, he worked out that the Stiebel Eltron plumbing diagram didn't include a valve that we needed. Once that was fitted, it has been working great. He even got the Stiebel Eltron engineer to come out to check everything, who also set up the weather compensation - albeit at 23 degrees which was way too hot, so I've been adjusting it since. The installer had set the heating temperature at 50 degrees which was obviously wrong, but he did say it was very mild in September (it was) and he would come back when it was colder to get it right. He wanted to ensure we had heating at least if the temperature dropped. 

One major problem we've had is the supply of parts. The controller provided was an older model (works okay) as the new WPM4 is not available. Plus the internet service gateway isn't available and we've no idea when we will get it. I know Stiebel Eltron have had issues securing chips, plus there has been huge demand for ASHPs in Germany for obvious reasons.

Our installer was a small company called Orange Energy, who I'd say was straightforward and did keep coming back to try and fix the initial problems (putting off other paid customers to try and sort ours). I do think he could have been a bit better in explaining weather compensation, and especially how to set the Grant unit. The Stiebel Eltron is much more straightforward and I've been adjusting it and getting it to be more efficient - I just wish we'd had the WPM4 unit which we ordered though. 

@knukes Hi, thanks for sharing. The Grant weather compensation parameters are quite straight forward to adjust once you get into the settings in the less-than-intuitive controller. Grant publish very little information in their installation manual about the controller and the features, I think this is intentional, because it could get screwed up quite easily. It factory defaults to give minimum water temperature supply at +20degC and maximum at -4degC. It's all adjustable in the installer 'INST' level.

I'm in the process of 'suck it and see' on a fairly new Grant 10kW ASHP install, to see if the compensation is set about right. I'll know in the depths of winter if I need to adjust it to improve CoP if I can get away with a lower supply temperature.

@allyfish I think I still need to spend some time getting my head around this! Thank you though.

Mine was so bad Mars wrote an article on it.  But for the installation itself.  No handover, flow temperature at 55 degrees, no weather compensation, hot water return pump running constantly - frankly they had no clue and were just plumbers (and not especially good at that).  Make good was poor.

Since joining the forum and with the help of Vailant's excellent customer service we have a heat pump running well and efficiently.

@witchcraft Sorry to hear that. I'd read your article and it does sound like a really shocking experience.

I suspect most people on here are the sort who like to work things out and gain a greater understanding of what is going on. Not everybody is like that though and they need to be confident when they pay for heat pump installation they get a proper service.

As I've gained knowledge through going through this process, it seems to me that the biggest issue is the lack of consideration of efficiency in heating installation. For example, I wonder how much excess gas has been burned over the years through poor and inefficient installation of boilers. Because gas has been cheap and nobody really noticed, boiler installers basically whacked it up, home owners got heat and were happy. But the energy crisis has shown us that insulation, efficiency and electrification now has to be the solution.

Hi. I've just joined the forum and spotted this post. 

I've voted average but actually feel it's closer to poor. I was very lucky to have a full system fitted on eco4 as my father in law is on ESA after a heart op. I've had a Samsung gen 6 12kw ASHP two zone fitted with new rads and pipework throughout. It's an all rad system, no UFH.

It seems my experience is fairly common with others who have had ASHP fitted on eco4. Basically the system is put in as quickly as possible and left on high defaults, no legionella (which I would turn off anyway) and told just to turn it on and off with the room stats. I'm not one to do as I'm told so I instantly started researching to find out about WC etc and how to make it more efficient. I've learnt more everyday. It's no wonder ASHP has a reputation as being expensive to run as it would be if I'd just left the system as it was handed over. I imagine most people do just that.

There needs to be a lot more education for fitters and from fitters to end users. ASHP manufacturers could make them a lot less confusing too. 

Our experience mitsubishi ecodan 11.2k

New build, zero information told by installer to set and forget at 60 fixed flow ( roll eyes), after loads of research we have finally got the system working both efficiently and the house is warm.

We have no gas in the village we live in, so ashp on paper looked like the best option. When we moved in we had no idea how the system worked, from an end user perspective felt like we were chasing the elusive "sweet spot" which is ridicules and very frustrating, tech should just work in my opinion.

What worked for us was that we bought another wireless controller that we added to the system then after placing it around the house we finally found the correct placement. (Another eye roll, really should this not just work whereever it is placed)

The house is now comfortable on weather comp. so far this winter saved 220kwh on last year, target temp is 19 but always overshoots, which suits us fine.

I do despair for most end users, its not an easy set up to understand  and can be expensive without loads of research and help from this forum.

Voted average, but verging on poor. We have been trying to contact the installers since Sept for a service, thankfully the system is working OK.  On the Mitsubishi website the installers are still accredited, should this be the case? if they cant even respond to customers.

Voted average for a vaillant installation 

No heat loss calc provided, no design provided. Installation done blindly due to poor communications from installer. installer basically connected the pump with no instructions on how to use - I suspect this is to increase the number of their call-outs at costs. Pump is oversized, not insulated which indicates loss efficiency and I’ve had to do a lot of research to try to understand what is going on. Still ongoing issues. Very mixed feelings.

Posted by: @gemiar

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No heat loss calc provided, no design provided. Installation done blindly due to poor communications from installer. installer basically connected the pump with no instructions on how to use - I suspect this is to increase the number of their call-outs at costs. Pump is oversized, not insulated which indicates loss efficiency and I’ve had to do a lot of research to try to understand what is going on. Still ongoing issues. Very mixed feelings.

If that gets an average vote, I wonder, how bad do they have to be to to get a poor/absolutely shocking vote?

@cathoderay Based on the questions they got an average score, if you asked me my views they were charlatans who had no concept of how ASHPs run nor any idea of customer care or service.

@gemiar, welcome to the forums and thanks for sharing. Please feel free to start a new topic for your set up and let us know what your running costs are like, which you can do here: RE: What's your current daily damage?                                    

@cathoderay well,  I am being generous here. I do get hot water and heating but at excessive cost. It’s ongoing and I am trying to educate myself on what expectations with ASHP should be - I’m a consumer with no technical plumbing/installation knowledge. The installer also uses this to their advantage sadly. This forum has been really helpful.