JohnMo

Pretty easy, add counter battens. These will jive you a thermal repeat break as well. On mine I did 50mm packers then 50mm counter battens on that to give an additional 100mm.

Only risk is it against the law and BC can tell you to make good everything the way it was before you started. Other than that I don't see many issues.

Buy a pump with built in thermostat and timer. Set thermostat so water is at a comfortable level - not super hot. Only time when you are likely to be there to use the tap. We have to our ensuite (20m from cylinder), only have it on first thing in the morning. I shower at night, and don't have secondary circulation on then as it's not needed, start shower when a go into room, by the time I'm undressed and finished messing about, the shower is almost hot anyway. A visual of what it does, from this morning, a temperature measure of the cylinder in orange and the other is the water flowing out of the top of the cylinder. So pump effectively does two short runs over a 3 hour period.

Ask them 3 quotes

That isn't how you run a heat pump so why do that with A2A (which is a heat pump)? You keep on top of the temps and run low and slow. So when sun is out, the house starts to heat up and cooling starts then. You can always add a battery then it's still powered by solar overnight as well.

Not sure what was risky about PV, domestic systems had been about since the 70s, just super expensive. Once the feed in tariff disappeared, funny old thing prices dropped like a stone. Not sure where your job fits in to the discussion! Doing cooling when powered by PV, is better than heating and having to take energy from the grid. Even better if your getting paid 75p per kWh while you are doing it, whatever the inflation index is used. But not that great for the tax payer.

Let's step back a little How do you pay for your energy is it via a heat meter? Think I see one on the top of first photo on the left. You can use the heat meter to help set up the system, it will tell you flow rate, instant kW, and dT. So use this as a performance monitor. You need to pulling as little kW in as you can get away with. I would be doing it all low and slow, running UFH at 60 - not sure. I assume hot water comes in through a plate heat exchanger? And you pay based on how much energy is extracted via the plate exchanger?

You need to be careful with voltage drop on the AC side. The inverter can trip if grid voltage is high and you have a voltage drop. You are better taking the voltage drop on the DC side. Turn into a shed, then it's not a ground mount array.

It's doable and works. Ran the gas boiler hydraulically separate via a large 40 plate PHE. Control was outside the heat pump, so heat pump and boiler ran their own control. I had mine set to do gas at about 5 degs when defrosts start to happen. So at 5 degs when the compressor cycled the flow temp was low enough for the gas boiler to step in. From that point the the gas boiler ran. I did hybrid DHW all the time, so 210L cylinder with a max flow temp of 60 from the boiler, with a very low ramp rate set in the boiler. Heated cylinder in 20 to 30 mins. During the cylinder heating the ASHP and gas boiler would slowly ramp up together. Downside on any decent electric tariff you have a cost penalty - running costs are lower even at cold outside temp, its close to zero all day today, so in the defrost zone and average CoP including DHW is 3.4, paying 14.33p per kWh, is still only 4.2p per kWh. Yesterday would have been an all gas day on the hybrid system and the costs would have been about double compared heat pump (on Cosy and battery). Gas I assume is about 7p and you have a standing charge to pay. So no longer have gas connected - just isn't worth it.

That sounds good until you read the rules "Shading must be avoided" how do you avoid shade on the west panels in the morning?

Some have a option to add ventilation and air mixing to manage humidity. More to stop air drying out too much, rather than ventilation.

If doing that on two roofs, the amps produced follows the lowest output panel, so if you had a side in shade and the other in the sun, output of whole system would be equal to the shade side. You can get around it with optimisers, but not fully. Each side of roof needs it's own MTTP. Plenty of cheap string inverters with 2x MTTPs. City Plumbing is my go to, for solar.

Decrement decay is real. The other issue is noise transfer. SIPs are quite noise transparent, ICF aren't. Are you comparing similar U Values?

Nothing be careful with price, current adverts look more expensive than new for panels. I have a fully second hand system and bought a inverter the same as the the one above (just slightly bigger) second hand, no issues. cool energy do a diverter, it will drive two immersions one after the other. Other brand tags for the same item, selling lots cheaper, so do an image search - may have to wait for it come from China.

Just run a timer. Octopus offer a similar tariff to cosy for storage heaters. Nothing wrong with a smart meter, saving me a fortune now it's up and running. My heart bleeds at the 75p per kWh generated whether exported or used. Madness they get that much.

Resistive heating via a storage heater, is a good solution for many properties, especially if the electric price drops. A passivhaus with low heating energy use a simple solution.

The reports aren't really saying scrapped, going back to the first first post of this thread and the links article "The move will mean restricting heat-pump subsidies so that only those receiving certain benefits will be allowed to claim them, sharply bringing down costs to the government" So adding an element of means testing - your rich enough you don't get the grant. Suspect the same will be true A2A etc also.

Aren't there are only 4 MC4 connectors per string that aren't factory made. The panels just daisy chain together using factory connections. Then you have the +/- leads to inverter. So you need to make up 4 connectors in total. More strings equal more connections.

Ask others? Are you talking to them? Phone them.

How often do you inspect - if it's that bad, maybe up the inspection and replace frequency? Small mesh can equal frozen inlet in winter or an issue you need a ladder or scaffolding to fix

Ask a plumber?

You experience the ventilation heat loss on heating days only. Plus you experience it based on dT between and outside, not a set figure every day. Plus if you do demand based the ventilation heat loss is proportional to actual demand, not a steady state.

Some better looking stuff on here https://www.aereco.co.uk/products/air-inlets-uk/eht2/

https://www.bpdstore.co.uk/glidevale-fresh-99hdb-humidity-sensitive-acoustic-wall-ventilator/p/232 The first one I came across

You can buy then with acoustic sound deadening as well.