JohnMo

But would say big grant, but you pay big admin fees to get grant and installer adds a premium - or it's a rip-off You pay 2x standing charge, been there son went direct heat pump. Solar is great in summer a d rubbish in winter 0 That's why you do full heat loss calculations, so you know they can. I just heat our DHW via immersion, that leaves the heat pump to do what it wants to keep house warm. Current only pay 10p per kWh off peak, by the time you factor in all the inefficiency of gas it not far off the same price in real terms, maybe cheaper if you factored in standing charge in the summer months.

If you haven't paid for construction drawings you will not get them. It's more normal for the architect to do them, again you pay extra.

Welcome. Sorry I'm the polar opposite, had some home automation and basically stripped it all out, preferring simple light switches etc. use home assistant only to monitor stuff now, but generally it controls nothing that matters.

What do your plans actually say about roof angle? Big difference between 12 degs and pretty much flat. Our 12 degs roof is 2.5 block work one side of the building and closer to 3.5 to 4m at the other (staggered wall).

1026 kWh are you sure, that is correct - I have 9-11kW (added another 1840W just recently) of panels and 7kW of inverter in NE Scotland, so far this year at nearly 4000kWh. Plus most my panels are vertical, so optimised for winter production not summer.

Yep, volts is key here, low volts mean big amps and big cables. So if your battery is 48v dig deep in the pocket, it won't be cheap. Have battery and inverter close.

Google says 2.86 degs, long way off 12 degs.

Our lounge is all glass on one wall but to make things worse it comes out to a peak to form a bay window 6m tall. So we get Westerly sun which circumvents the roof overhang. Fine mid afternoon. But on the upside we have only used 144kWh of electric doing cooling this year, getting SCoP of 6+. All of that supplied direct from PV. So missed out on £17 of export.

Datasheet confirms 12 Deg is ok gse-in-roof-datasheet.pdf

GSE trays can go on a 12 Deg roof I believe, they would displace the steel roof where installed. You may need to clean the panels regularly as the self clean function wouldn't work well at 12 degs.

Oh to have the solar output, we have 11+kW of panels, but lots of trees and up in Scotland. We almost never import expensive rates always cheap, but our bills are still way higher than yours. But still very low in reality. Considering we cool most the summer months and shoulder months as well as well. But yes even so the battery is allowing all our current electricity to come in at 10p instead of 27p(?). We seem to consume around 10,000kWh, so even without any export or PV we save £1700 a year. So battery is about 2.5 years payback.

So not a flat roof (for insurance purposes). You can have them on a 12 Deg roof, but winter performance will be utter rubbish. So I would tilt on stands to to a higher angle. Depending on width of roof the panel could go on the low side and still be below the ridge height and be tilted up.

From a personal perspective having lived with intermittent fans for most my life, then experiencing dMEV, there is zero chance I would let an intermittent fan anywhere near a house a lived in ever again. Generally poor performance and f'ing noisy. dMEV are silent and use next to no energy. Coupled with smart humidity sensing only boost when they really need to to (Greenwood CV2 or CV3). So no connection to light switches etc. Add some humidity activated trickle vents you have a very smart system that actually ventilates and only just enough to keep house dry.

If that's the case you may need max flow temp from boiler to get anywhere. Turn your thermostat down to what it achieves, then that is the simple no cost solution. Walk away and have a cup of tea. Other than that your options are spend money. External plate heat exchanger and pump or new cylinder with a big coil (do 3m²) then you can flow at 60 degs and get 55 Deg water and heat in about 10 to 15 mins.

I used 45 x 50. But it depends what you need to run in the cavity. Our ceiling lights needed just under 50mm to get the ballast in. If it's just cables 25mm will be fine. But if doing again I would use a wider section of wood so less likely to split near ends. Also consider the spacing between battens and what plasterboard you use. I did 600mm centres and then had to add additional to support the plasterboard correctly.

Not sure only importing in winter is practical, rainy days generation is pants any time if the year. We import all year, but export more than we import most of the summer. Yes we have lots more panel capacity compared to inverter capacity. The inverters rarely run at max capacity anyway. But we have tried to optimise for winter rather summer as summer you over produce anyway. But with big arrays you really need to export and import most the year - we do in NE Scotland, maybe different 500/600 miles further south.

You maybe took as long to write the above that it takes to make 20 of them. For the cost just buy some pipe

So maybe the 30 year old cylinder is showing its age and it's time to buy a new one. If you do get one with a big coil for fast reheats and heating at a lower flow temp. Maybe scale on the inside of the cylinder protected, but could just as easily be bunged inside the coil. So you could clean with chemicals. But a 30 year old cylinder the risk is yours to take.

So are you on an S or Y plan? Assume you are. If so the flow temp of the boiler will be the same for heating and DHW. So would suspect you have turned the flow temp down to be efficient, but you now have a flow temp too low to heat cylinder. Set to 70 degs flow temp and see what changes

You and around another 1.5 million registered installs completed prior to 2024

No. Except the builder shouldn't be charging you vat anyway, if he is installing the parts he buys. His service to you should be free of VAT.for goods and service. Trust us nothing to do with the subject.

Just did a Google search Bi-directional RCBOs became officially mandated for domestic installations with generating sources on July 31, 2024, following the introduction of BS 7671:2018+A3:2024 (Amendment 3). Manufacturers began releasing compliant domestic hardware around early-to-mid 2024. So lots and lots of installs done prior to that date, so doubt they were retrofitted. Our install was done in 2021 way before bi directional were available.

How many homes have 2 way RCBOs/RCDS with solar currently - suspect not many. Does yours?

Yes, UFH/cooling in house

A typical 400W panel is around 1134 x 1722mm, so that X2.