JohnMo

Mine actually run outside to a summer house and are all boxed in. They pop through the summer house wall.

I would just do Hep2O and then slip on insulation. Depends on flow rates you need, but ours is done with 15mm.

Shows decisions can be made and quickly

Straight in to nearest plug socket - done. But only 800W max, most the time it will be a quarter of that. All without MCS, so nothing is paid for any exports.

The UK government has officially legalised "plug-in" balcony solar panels, allowing renters and flat owners to generate their own green electricity. The legislation (SI 2026/848) takes effect on 27 August 2026, making the UK market look much more like Germany, where similar plug-and-play kits are highly popular. Key Rules of the New Legislation Plug-and-Play Setup: You can mount the panels on a balcony rail, terrace, or patio and plug them straight into a standard 13A three-prong wall socket without professional electrical installation. 800W Output Cap: Systems are strictly capped at a maximum power output of 800W per household to ensure the safety of domestic wiring.Safety Certifications: Only fully integrated, compliant kits meeting BS 7671 (Amendment 4) standards can be legally sold or used. Location Exception: While the law allowing retailers to sell these kits applies UK-wide, the specific rules legalising direct socket-connection currently only cover Great Britain (England, Scotland, and Wales), with Northern Ireland still awaiting an equivalent regulatory update. What This Means for Renters and Flat Owners No Installation Costs: Because the system uses a regular mains socket and doesn't require complex roof wiring, you avoid expensive professional installation fees. Portability: If you move properties, you can simply unplug the panels, pack them down, and take them with you to your next home. Immediate Bill Savings: The power generated feeds directly into your home circuit, meaning appliances use your free solar energy first before drawing paid power from the National Grid. A Note on Tenant Agreements - While the technology itself is now legally approved for standard electrical use, you may still need permission from your landlord, local council, or building's management company to physically mount equipment on exterior balconies, railings, or communal walls. So 800W PV plug and play kit solutions only. Does not apply to batteries only PV.

18 degs is generally above dew point so most likely not

You don't need to, plug in batteries are almost here, if they want batteries they will have them like it or not.

If MCS or octopus approved why not higher export rates, they are not limited to 3-4p kWh.

All build methods can achieve that. Specify exactly what wall thickness you want, because its normal for say 140mm, nothing stopping you saying I want 200mm, then do it in I beams or posi joists style. If restricted to 140mm and then apply counter battens to increase wall thick and get rid of most thermal repeat bridges. Then any high density insulation you want.

You could always add a bit more screed - but that cause many other issues, now I have written it down.

Would agree normally, but multiple houses was mentioned, so would assume one string per house with it's own inverter. Unless @Beelbeebub is doing lots of kW per house. But not knowing the full layout logistics will decide the final cable spec

DC circuits use resistance calculations only. This makes voltage drop simple and linear: V = I × R. Definitely do minimum of 6mm² any smaller you are wasting power. Then you are at or below 3% voltage drop and for a minor uplift in cost. Most panels these days come with 6mm² tails not sure why you would down grade them with 4mm². Do multi core then one cable will carry multiple strings, so 4 core two strings etc. easier to route one cable instead of loads.

Doing long distance AC can lead to inverter switching off depending on the voltage of the grid at the house(s). Taking a voltage drop on the DC has zero effect. When doing the AC over the distance the inverter has to produce more volts to overcome the AC line voltage drop. One of my arrays has 80m of DC cable zero issues and cable isn't that large. If doing DC make sure the voltage is high, low voltage DC for a given amps is big, high voltage for a same amps gets smaller

@saveasteading did - not you, so no idea why it says you did - strange

Trouble with averages they don't really tell you that much - 26p is because nearly everyone is on a standard tariff. I live in the UK and currently pay 10p for all my electric at most, summer it's mostly free. Others pay less and many pay more. I have a hot tub always at 37 degs. Summer use is supplied via solar and battery, it's also heat pump heated, so uses very little electrical. But Scotland is 0.02kg CO2e / kWh and produces more than it can consume at lot of the time - not always. But I'm with @saveasteading charge high users, they are the ones that add an extra power station or result in a gas powered station being started. Generating more or providing more water so people can water the garden cheaply or build or live poorly insulated houses, why? European countries are having to reduce output, because water is in short supply for cooling or just warmer than is helpful.

You can strip with paint stripper's but it tends to leave a raised grain. You could simply sand it down. Or paint the other windows to match.

So can most areas of the world

Yep

Any option that includes PIR is a bad option as it noise transparent more or less. Why not a heavy structure instead of the lightweight ones suggested i.e. concrete blocks, woodcrete ICF etc

You need to bury below deep plow depth. Although sheep today, you have no idea what will occur in year. So that is 910mm to 1000mm

I bought a DeWalt main powered - during the build I used it loads. Great tools.

They should be using a floor moisture tester.

The second floor UFH will ensure the incoming water will get warm in winter also

If you don't really need to bury l wouldn't - would surface run, then you can see them.

Bit like this