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No specific knowledge here but I am curious: 1. What is your current plan? 2. They claim to support dual zone heating with different temps? I'd assume so. How are they doing that? 3. Are you referring to purely simultaneous cooling? Can it do one zone at a time at different temps? I have a couple of ideas for things you could do but depends on the proposed setup.

Looks very much like you have a manifold like this: https://ambienteufh.co.uk/product/stainless-steel-underfloor-heating-manifold/ The ports on the far right are fill/drain valves I think.

Sounds like maybe a step back is in order. If you want to export you need DNO approval. AFAIK if you don't want to export you can get inverters and set them to not export and not worry about the DNO. eFIXX interviewed someone who got e.On to approve a non-MCS install for export too (though the whole install was don't by a qualified electrician).

Isn't that the majority of houses that have a cavity? I thought the bulk of houses built with cavities without insulation had now been filled. Obviously there have been a variety of techniques used and problems identified with some but it's been step three of improving insulation in houses since the 80's. 1 and 2 being loft insulation and double glazing.

If you have the space AFAIK there are services you can sign up for that basically put you on a list and when a tree surgeon has a load they want to get rid of near you they will know to call and ask if you want it. Zero cost because they usually have to pay to dispose so its a benefit for them. Though obviously you need enough room to take a decent sized load of chippings.

Did you find any issues? Assume it's been working fine since the incident?

I think it's a fairly common option (in other countries) to use a compost pile to heat greenhouse during winter. Heating a house is a whole other level, maybe if you have a small farm.

Looks good. Congrats! Beer time!

But if you are paying the original installer to do it vs DIY then the benefits might not stack up. Can't imagine an installer would get out of bed for a job thats not costing £1k,

I'd hope the grid aren't designing around this. They have to design for the hottest day of the year being the longest for sun anyway. On any modern solar install where roof space allowed, the inverter on days like that will max out before peak sun is reached as there will be a certain amount of pv overprovision. So adding more panels won't significantly increase load to the grid at the most critical time. Yes it might stretch the load out over a longer time but the difference should be marginal. The benefit of more panels is to generate more in cooler/less sunny conditions where overheating won't be a problem (if the grid can cope with peak inverter load as it should be able to anyway).

I think you need to worry about notificatoin if you are on FIT. Non-FIT I dont think it matters unless you change the inverter. Adding extra panels to an existing inverter needs careful thought though especially if they are in a different orientation. If you have a spare MPPT then its easy, if not then needs careful thought.

Are you looking at the manufacturers site? https://www.edilteco.com/en/catalog/thermal/eps-beads-coated-by-e-i-a-additive-politerm-r-blu/politerm-r-blu Not sure that's the exact product, just the last page I was looking at, following through from the site Nick linked.

Could save a lot of labour if trying to lay a lot of insulation. Is this viable as an alternative to the EPS300 under insulated slabs?

Do you have any photos from when the work was being done?

That seems like a lot more effort and cost than normal boarding.

I've heard it called a level 5 plaster finish though I'm not sure that's entirely the right term in the UK. It's done at the plastering stage not painting stage, though I'd guess you could do a lot of sanding to get there.

Oh sorry. Was thinking it was the Chongfu one. Less likely an easy fix then if it's not a fluke.

Concerning. Definitely possible its a fluke but if it recurs I'd guess something on the control board is faulty and that will be a pain to investigate. I'm just a hobbyist but I'm a little doubtful an overvoltage condition would cause a PFC overcurrent error as the PFC circuit should self regulate whatever the voltage. About the easiest to fix 'electronics' issue that might cause this is bad capacitors but the input capacitors are generally fairly robust. Having said that, your HP is a Chinese up and coming brand rather than big name so maybe they cheaped out there. Edit context: The most common PFC circuits work by boosting the voltage from the incoming supply to around 380-400V DC which is then used by follow on circuits. The boost works with an awareness of power factor so it draws more current at the peak voltage of the mains cycle and much less at the minimum voltage. AFAIK it will draw more current in an undervoltage situation, but it would have to be under by a lot I would have thought, ie, a brown out.

That's what I was thinking. You'd use a decent amount per board rather than a couple of screws. Glue is prob more expensive than screws but likely easier. I did pause after @saveasteading's comment as I did see someone talking about how their 'used once' container had paint peeling. My guess is that assuming you gave the surface a once over pulling off anything loose, so long as you covered a decent area with glue and weren't hanging stuff off the cladding it'd be ok.

Traditional PV to power a traditional electric system will be alot cheaper.

A string of 5 with a voltage less than half the mppt maximum is not going to perform very well, especially poorly in low light, it's operating voltage is too close to the startup voltage. Sounds like one string of 10 would work fine assuming the panels are all in one orientation and no shading issues. If you want to have two strings for shading, orientation reasons then maybe look at a different inverter or optimizers?

If just securing cladding with no structural purpose any reason not to use a flexible glue (CT1)?. Seems to me that would be easier, quicker and thanks to the flexibility possibly better given wood/metal will expand at different rates in the weather.

If you are thinking about something like this then definitely also look into waste water heat recovery. Might not work well for your floorplan but if it does I doubt it would cost significantly more to install than an electric booster and could reduce the need for heat input by 40-60%. Edit: I had second thoughts about this and went to check the specs. These things have a limited flow rate range so they lose efficiency if shared between showers they won't work as well, and installing one per shower gets expensive so it's not as clear cut as I initially thought.

They are basically electric showers with better controls but installed elsewhere. https://www.flexiheatuk.com/product/electric-instantaneous-water-heaters/

I'm sorry if anything I said comes across as this. Sometimes threads on here move away from the actual question and onto the theoretical. In this case the question was a about gas boilers and the early answers were about that. Then, as is common (and generally good) on these forums, you asked how an ashp user would handle this and we diverged off into the theoretical. For what it's worth I think @Indy is being completely rational to stay with gas given the current state of the heatpump market, ie, if you are not careful you can end up with an expensive and shit install. Given that the gas market is unlikely to stick around forever, I do think it wise to allow for a future change to heatpumps but in the near term, it's not wrong to stick with gas for a high demand house. Staying on the original question, the one point that is worth considering is whether the question would be better phrased as 'Whats the best way to provide hot water for 4 people to have long showers without a wait for HW tank refill' rather than asking for unlimited water. The answer may be different to that question than unlimited water, at the very least it opens up more possibilities which can then be compared on a cost/ease of install/maintenance basis.