Dillsue

Are you sure he uses the same every day all year round? If that's the case then you already have the figures in your spread sheet. If that's not the case and his usage varies then you'll likely export more in the summer and import more in the winter. Because of the difference in unit rates between import and export your figures won't be quite so rosey

How big an array you install is a personal thing dependant on lots of factors that vary in importance from person to person. We installed an additional 8.5kw of panels a few years ago on top of the 4kw we already had. No battery for us and no export payments at the time. All self installed and kit bought at discount prices. Having plenty of "free" eleccy and happy for the neighbours to use our surplus is a good enough ROI for me. Octopus now buy our surplus so a big dollop of unplanned icing on that cake:)

Will your neibours demand profile match the generation profile? Usually there's a big seasonal mismatch because you generate the most in the summer but use the most in winter. Total annual Generation can match total annual demand but because they peak at differing times they'll not balance out.

You're right that businesses can behave like that and have unbelievably biased Ts and Cs that they will throw in a customers face and stick 2 fingers up to complaints against them. Fortunately there's a piece of consumer law called the unfair terms in consumer contracts regs that effectively remove unfair terms from a consumer contract thus holding a business accountable if they've not delivered a service they've provided with reasonable care. Once the OP has worked out if he has a single or multiple contracts then anyone trying to hide behind biased Ts and Cs and shirk their responsibilities should be referred to said legislation.......it does work:) It's alway best to resolve things amicably though

G98 is factory limited to <3.68kw. Anything >3.68kw is G99. Anything >3.68kw that can be installer/user export adjusted is G99+G100 3.68kw is a fair bit of power and there's lots of G98 inverters that can have much more PV connected than 3.68. Solaredge allow 100% oversizing so their 3.68kw inverter can have 7.4kw of panels connected, and much more if the panels are facing differing directions. We have 8.5kw hooked up to one of our 3.68kw inverters but the panels are facing 3 differing compass points so the peak is reduced but generation is for much longer

The display on the front of our meter shows import and export readings. The In Home Display shows the import reading but I've not found an export reading. Can't see why the IHD couldn't show the export but maybe it just needs setting up?

If you go for a larger than 3.68kw system but export limit it, you can draw what you want but just not export it. Save peeing around with a second off grid system and the headaches that could come with 2 differing systems.

?? You said you can export all your PV through one hybrid inverter so its AC output likely powers the house/grid and would have your FIT generation meter in the output?? Maybe you've got a FIT system inverter feeding the hybrid inverter via the FIT generation meter??? I seem to remember you've got a complex system??

Unlimited export?? Are you sure it's unlimited? Why wouldn't you need to involve your FIT provider if you've increased your TIC?

Depends is the honest answer. If currently on a combi then you'll likely need a new DHW cylinder. If your emmitters are predominantly radiators then there's a fair chance some or all of them will need replacing/swapping round or additional ones fitted. To get the best out of the ASHP system you want accurate heat loss calcs so the HP and rads can be sized correctly. Having excess solar is primarily a summer issue so will likely have little impact on the economies of running a HP predominantly in the winter. Finding someone who can design and commission a system for you may take some doing. My advice would be spend a good while researching how to get HPs to work efficiently and what constitutes a well designed/commissioned system before you start talking to suppliers. You'll be better placed to know if they know what they are doing!

For G98 compliance the inverter must be factory limited to 3.68kw and manufacturer certified as such. If it can do more but you limit it to 3.68kw then it's not G98 compliant. It then needs a G99 application plus a G100 supplement to cover the set up of the export limitation. My very limited experience of G99 is that it's straight forward and worth the effort to get consent for the max your local grid will support. Imagine export payments being £1 a unit and your neighbours had grabbed all the spare export capacity:)

There's a circulation pump for the secondary/cylinder side of your PHEX in the schematic you've not long posted????

Isnt that the same as heating an indirect cylinder via an internal coil?

No idea if cool energy provide this but on post 2020 LG Therma VS there's two inputs for thermostat control, one to call for heat and the other to call for cooling. Might be worth having a trawl through the cool energy manual to see if they provide similar

Thanks for that. Hopefully Dave can share how he's "powering" the cylinder side of his PHEX without a pump.