Dillsue

Just check the max power available on the back up output will power the "heavier" loads. The Solis unit I'm thinking of using is a max of 5kw on the back up output so would need a bit of manual load management if we wanted to cook in the winter with the HP running

I think the grid disconnect is done within the inverter as it is with G98/G99 so no external changeover/disconnect needed?? In the second schematic the "on grid home load" will be dead in a power cut and the "load" will be live, fed from the batteries or generator. If the inverter can't sense a stable grid connection it keeps itself disconnected with internal contactors?? In terms of installers knowing the requirements for backup power supplies/generators, are they actually covered in the wiring regs to the level that the regs spell it out in black and white and every spark would know exactly how to wire things?? I've always understood it to be a bit of a grey area??

But if there's a neutral to earth bond, as in the schematic, anything the inverter might apply to the neutral line will run to earth?? I appreciate UK regulation/best practice may want the inverter neutral disconnecting from the grid as well as line, but if the neutral is earthed surely there's no hazard??

Wanting to understand more about this, what is the risk to the DNOs linesmen if the neutral is bonded to earth but the DNOs neutral isn't disconnected from the customers inverter, seemingly as in the schematic??

Its not electrically the same if the DNOs cable gets disconnected/severed which seems to be your concern?? Outside of your house isn't under your control but inside your house is, so you can ensure that link remains. If your inverter meets UK grid regs then there will be people at Growatt that understand the UK grid so should be able to clarify things for you??

As both the house loads and the inverter are connected to both the earthbar and neutral bars in the schematic, I take it that Growatt expect that E-N link to be within your house. It's a poor schematic if that's depicting the link to be out in the grid somewhere. Probably worth asking Growatt for clarification??

No idea about long term longevity but ours has been in since 2020 and works fine. The mat we used is self adhesive so sticks to the tanking membrane and then gets buried in a layer of tile adhesive. Tiles are laid in another layer of adhesive sat over the heating mat. Straight forward to install.

Maybe Im unique in the world as we removed a wall together with 2.5metres of kitchen units. If we'd followed the mantra of only piping open spaces, we'd have a big cold patch where the old units were.

And when you remodel the room so the areas you left unheated are now exposed and the areas with heating are now covered??

Correct that is a plinth heater but nothing to stop you installing a plinth fan to draw trapped UFH heated air from under kitchen cabinets which you seemed to suggest couldn't/shouldn't be done??

Aren't those examples of flexibility rather than redundancy?? Redundancy would necessitate doubling up on loops so if one failed the other can provide the full heating load, in my understanding of redundancy. You'd need to install twice as many loops and twice as much pipe if you wanted full redundancy.

Maybe not in your world:)

Yes, Yes and No! We did a large kitchen/diner with 100mm+ slab and pipe at 150mm centres, I think....it was 20+ years ago. We did the whole floor wall to wall so heated under cabinets and a partition wall. It's been great to have warm tiles:) If there was concern over loss of heat output from the areas under cabinets you could put a fan in the plinth to draw out the warmed air??

Assuming the walkin shower is tiled then put in an electric UFH mat. You can get a former for the shower area to give a fall to the drain, electric mat over the whole floor then tile over the mat. If you're getting batteries anyway and your solar is MCS accredited so you can get paid for PV export, then best £ROI solution that I can see is export everything you can @15p/unit and run the house off the batteries for much of the time charged @8p/unit on a TOU tariff. You'd need to work your own figures but my estimates suggest that's worth a few bob and worth recabling my PV so it's the first connection to the DNOs incoming supply so our new batteries can power the house while the PV runs to the grid

Me to with an older section of the house having 8mm micropore drops down the walls to the rads. Set on the slowest speed it pulls a steady indicated 10 watts. An easy way to retrofit a HP to small bore pipework:)