gmarshall

Cobalt is the only real issue rare elements (and geopolitics/human rights) wise, if you use LiFePo batteries (which most fixed systems are now- cheaper but heavier) then that issue goes away as they are cobalt free. For estimating costs I took an approach of considering a daily saving on a seasonal basis, i.e. 4 months of good solar generation, operating 95% off grid so effectively paying standing charge only, 4 months of poor generation load shifting cheap rate electric each day saving battery capacity x difference between the electric rates, and 4 months of shoulder season, which is a bit trickier to predict and probably depends on your generation and usage on the best model. For us, using that method I came up with about an 8 year payback for a self install 5 kWh system, with a 10 kWh offering no further benefit, and that is working as expected for us 6 months in.

Very pleased with ours, although I imagine there isnt mutch to choose between most of the different manufacturers to be honest. For what its worth my parents have a mitsubushi which is also good but in my opinion is slightly louder than ours (ironically they couldn't have a panasonic as the spec sheet says its too loud!) and the controller even less user friendly.

Yes, the installer service cloud (which anyone can register for) is what gives you COP (and lots of other) data. The user login is basic controls only with no data- although it does integrate with home assistant relatively nicely.

We used Allan Brothers for aluclad timber. They actually come from one of their sister companies in I think Denmark as their UK manufacturing is timber only. We were very pleased with both service and the final product, and they were our cheapest quote.

We are a 9 kW T-CAP. 60s detached house 110 sq m with moderately good insulation, ufh in slab downstairs, rads upstairs, solar divert to HW so reduced HW usage on the HP. Weather comp set to between 30 and 39 (@-3) December to date overall COP is 4.1, 3.0 for DHW only and 4.3 for space heating only. Year to date 4.3. Total electric usage for the year is 1834 kWh of which 315 is for DHW. A COP of 3 isn't awful and is possibly by being skewed if you are a high % DHW, but I agree I would expect more, especially with your very low flow temps. Our unit is deliberately slightly oversized so does get some cycling when it's not overly cold out, and we run it predominantly overnight during octopus intelligent off peak. Typically 6 hrs use overnight and up to 2 hours boost on an afternoon to 'top up'. If you haven't already I'd suggest getting a installer account so you can see if your unit is cycling badly. If it is, one thing you can do to partially mitigate it is to set it to 'pulse', i.e. instead of running on for 4 hours, you do 2 hours on, 2 hours off 2 hours on. This is what we do in the shoulder seasons as the HP will run nicely for a hour or so and then start to cycle. Giving it a break for the heat to dissipate from the system allows it to start over again and improves the COP. A delta T of 3 also seems low- ours is 5 which I thought was pretty much universally considered best, so might be worth a try adjusting. I think you are firmly in trial and error tuning territory. Ideally you want a week of stable weather to try different things and see what works.

I don't think there is an app- I usually acces it via my laptop as the graphs are so detailed they are hard to read on a phone

The service cloud is what you want- more data than you could ever wish for in there! Just follow the sign up link from this page https://aquarea-service.panasonic.com/

Essentially we just run the system on weather comp with the thermostat set to a high temperature (25 degrees I think) during the off peak period, this then ensures the system runs during this period and puts heat into the building and the slab, on all but the coldest days this was enough for us last winter. Took a few tweaks of the weather comp curve but this is easy to do (and fairly satisfying if you like that sort of thing, and if you get the WIFI dongle thing as part of the heat pump set up you can access a lot of data that is useful for this via the installer portal that anyone can register for. I'd advise a wired ethernet cable to it though as otherwise you are trying to get a wifi signal in a faraday cage which can be frustrating!) The room temperature started to rise towards the end of the heating period and then fell slightly over the rest of the day. Room temperature variation no more than 1-2 degrees over 24 hours downstairs, and if we needed more then it would kick back in during the afternoon to top up, but this was no more than 10-20 days all winter I think. We were on old fashioned ECO7 electric last year, hoping the 6 hours on Octopus Intelligent this year will still do the job most of the time (and the cost saving means a few extra afternoon runs is no big deal). Upstairs, the radiators give more responsiveness, but also much more temperature variance over 24 hours. Without them, I think the temperature variance would be even greater. We put in an entirely new system using standard double panel 1.2m rads in each room. I dont think the single panels we also inherited would have been much use, and i equally had no desire to let the contents of that system anywhere hear the UFH manifold or HP! We are in Nottingham on a Panasonic Aquarea 9kW T-CAP J Series- will DM you. On the planning question, if you have full planning permission with no conditions relating to the HP, then as @JamesPa and @JohnMo say, you should be good to go. Noise complains are noise complaints regardless of installation route, but if what you have done is sensible and in keeping with the ethos of MCS020 the I would be amazed if you ran into any serious issues. My parents have just had to jump through a series of ridiculous hoops for their install as proximity to neighbours meant that the installation was outside the scope of MCS020 that resulted in a full acoustic survey at excessive cost. It is all sorted now but a real example of how silly the planning thing can get- fingers crossed you don’t end up with any daft questions from planning.

I await with interest to hear what you get out of this- we really do need political pressure to change all this nonsense!

In the unlikely event of it being queried I think presenting your MSC020 calculations would be well received by most reasonable individuals (not commenting on the reasonableness or otherwise of any particular planning departments...) There is also the fact that the average modern heat pump is quieter than the average boiler flue!

The planning situation is certainly madness on many levels, but given the stipulation is that it meets the MCS requirements, as long as you download said requirements (MCS020) and apply then yourself (they are pretty straightforward and the only specialist equipment required is a tape measure) then I don't see how you could ever run into a serious issue. Returning to the other points raised by the OP, itsound like you have a very similar setup to us. We have a 9kw Panasonic in a 60s detached house (120 sq m, decent insulation, ufh downstairs, mvhr, but fundamentally still a 60s house!) that works brilliantly, most of what you are saying sounds perfectly sensible to me. To go through your post - Our heat loss cals were just under 6 kW,so similar to you. The spreadsheet on this site is as good as anything. We went for the 9 Kw unit principally to ensure we had some headroom for a future extension. Any bigger would be massively oversized and short cycle (more on that later!) -20 mm pipes at 100 mm centres certainly won't hurt, but seems like overkill to me- we are on 16mm @ 150 centres which is more than sufficient. - The Panasonic units have good weather compensation, ours from memory is set to something like 30-38, so your assumption of an average of 35 is sensible. dT 5 is normal and works for us. Our space heating sCOP for the last 12 months is 4.5. We have UFH downstairs and rads upstairs. My only concern on your design would be the lack of upstairs heating. Even with our rads upstairs downstairs is noticeably warmer due to the constant heat of the slab. This may be because we mostly run out HP overnight on off peak electric to 'charge' the slab with heat which is very cost effective. It's fine for us, but I don't think it would work without the rads upstairs. Happy to answer any specific questions - we were MCS install as we caught the end of RHI, but I was pretty involved in the design and setup (I know the installer through work) and would definitely self install now, they are fairly simple intuitive systems really.

Or you can just use expanding foam adhesive?

We have Allen brothers aluclad windows with entrance doors that have aluclad frames and timber doors based on their advice that the aluclad doors scratch easily with keys etc. In my opinion good advice, but they do a full aluclad door if you want it. Our door is painted timber outside to colour match the windows and frame and pine inside.

We have exactly the same scenario and have one from B and Q that fits well in a 600 DIY kitchens drawer. Not sure about larger sizes, but they had a decent range I think. IKEA drawers are a different depth so theirs never fit other manufacturers.

There are solar diverters that can, in principle do this- I believe the Eddi with the optional relay board installed is pretty much the only option at present. The issues above all stand about available power from solar being low, and you'd need a big solar array to fully supply the heat pump, especially when the water is getting up to temperature, but technically, it can be done. Practically, I think almost everyone just uses the immersion as it's better matched power wise and simpler/cheaper to do, and supplies many peoples DHW demand for much of the year. But if you had a big DHW demand I could see the advantage of using the added efficiency of the heat pump. Eddi manual - see page 60