Rob99

Quick question on PVGIS data..... Can I assume that the hourly data output uses UTC and not local time? The PVGIS user manual doesn't seem to say one way or the other.

Yes, go with this. This avoids any possibility of the trees becoming a consideration in your planning application. If you leave them in place you will need to mention their removal in your application. Don't take the risk that some neighbour complaint results in the council tree officer wacking a TPO on it and killing your application.

What sunsync inverter model did you go with?

Don't think I mentioned anything like that...

Ah yes, makes sense otherwise you'll need 4 seperate strings and AFAIK inverters tend to come with 2 MPPT max

Quote from an FB group - Octopus say "nobody can swap to flux right now and they don't have an ETA for when that plan might be available again" That pretty much kills some of the economics for my planned PV system 😞 Just did a bit more checking - apparantly if you're on an existing Octopus tariff you can still switch to Flux. You can't switch direct if you're not already with Octopus

The process depends on your local DNO. For mine, where UKPN are the DNO, they have an online process which will give you automatic approval for install and inform for anything up to 5kW. Higher and it is an application and wait for approval process. Another classic case of making things inconsistent across the country!!

Have been doing some research into panels and optimisers for my planned PV and there seems to be a view now that, unless you have some really bad shading issues, optimisers don't help output that much (and can reduce it) as modern panels and decent inverters (e.g. your sunsync) are very good at managing shading now. Apparently there's also been some major firmware issues with some Tigo optimizers which causes issues. Blog here.

On the contrary, Loxone have had proportional radiator actuator valves running on batteries for several years.

It's different with gas. Every gas fitter has to have an individual registration with gas safe.

So, any business could become MCS certified by sub-contracting the various elements (electrical/heating) to competent electricians and heating installers). No wonder there are so many out there now. Does make me wonder now though...........!!!

Another classic case of inconsistent rules misapplied by jobsworth planning departments. As far as I understand it, MCS installations under permitted development don't have the 10dB below ambient requirement and don't have to prove noise levels with a noise survey or anything. They really are making it impossible for well intentioned people to do the right thing.

For me, this is one of the biggest issues and sadly indicative of the big developer lobbying that must go on with government/planners etc. There are a lot of new build housing sites in my part of the south east and driving past several over the past year, without exception every single house has a gas boiler and no solar panels. Clearly developers won't add them as it adds to their cost model and few people would be prepared to pay the premium for heat pumps and solar. Planning and building regs should compel every new home to be fitted with a heat pump and the roof covered in PV. It's unfair to expect existing homeowners to pay for an overpriced MCS heat pump installation whilst developers get away with it. Retrofitting heat pumps should NOT require planning permission and if permitted development it should NOT require to be an MCS installation. Whilst on the subject of developers, I also understand that some water companies are now paying developers up to £1,000 per house to "encourage" them to fit low water usage taps and showers. It won't cost developers any more to install them so why aren't they being compelled to fit them anyway. I don't want my water bill charges to be used to subsidise developers costs so they can make even more profit.

That's quite interesting. I wonder if the MCS data makes some assumptions which isn't part of the PVGIS data. Also wonder whether there's a commercial element in this too whereby MCS don't want installers or themselves to be criticised for PV generation estimates which don't materialise and therefore use much more conservative figures. Yes, that's true with shading although I have been quite surprised by how much sun actually falls on each roof slope as the sun moves around. The pitch is 35deg so not huge (its why we never ended up doing a loft conversion 😞) Each array will need to be on a seperate string so will have to make sure I source an inverter with at least 2 MPPT controllers. We also have a bit of shading from trees which shades between 15-20% of the East array in the first couple of hours of sun and around 10% of the West array is shaded very late in the afternoon for no more than an hour. Having looked into optimisers I don't think they wil be worth having as panels and invertors these days seem to be designed to manage shading really well. I've downloaded the hourly data from PVGIS for the whole 16yr period and dumped it into excel (all 280,000 rows 😱) and will now spend some time pivotting and analysing the data. Your generation of 4.26MWh seems pretty good if your inverter limits output from your PV arrays to 3.8kW

That's good to know. Do you have any shading at all on your array which might account for the slight reduction? Oh, and what size (kWp) is your PV system?

After a bit of a false start on this last year I’m looking again at a PV system for our house. We have East and West roof elevations suitable for panels and I intend to max out the kWp of the array as I just want a “one hit” roof install without revisiting later to add any more. First step I’ve been looking at the PVGIS database and modelling output on East and West. For initial purposes I’m using 5.39kWp (14x385W panels) on the East and 3.08kWp (8x385W panels) on the West. I’d always thought East and West were poor cousins to South but PVGIS shows East as generating 4,647kWh (86% of array max) per year and West as 2,297kWh (75% of array max) per year. This seems high to me but do people find PVGIS outputs to be a good match to real world outputs of installed systems? I’m going to start modelling generation against usage so I can size the invertor and battery correctly but don’t want to just blindly use the PVGIS data if it’s over-estimating. I've attached the PVGIS results for both. West-PVGIS.pdf East-PVGIS.pdf

We have 3 Velux windows from when we extended/modernised our house 4 years ago. We had a price for electric ones at the time but it was more than we were able to afford and "stupidly" with so many other things going on with the house I didn't think about running cable until after the roof was finished and ceilings boarded and plastered. I'm now looking to automate the roof windows so I can connect them to our Loxone system and am looking at using the Velux Integra KSX 100K upgrade kit. This has a rechargebale battery and a solar panel so doesn't require a cabled power connection. Does anyone have experience of retro-fitting these openers and how successful have they been? Or is there an alternative approach (other than the long pole we currently use) ? Cheers

Yes, conduit (providing it is large enough) will be better than just running the cable through insulation as there will be a degree of air space around the cables

Yes, if you run cable through insulation you will need to calculate the derating so that you end up using the correct size cable. BS7671 provides all the info and methodology so your electrician should be able to work it out for you very easily. If you're going to use conduit then that's a different scenario which will give you a different result. Legal copies of the BS are not available online (unless you have a BSi subscription) as British Standards are expensive to purchase and there are copyright issues uploading any extracts. Is this just a one off cable or will there be many of them? If it's a one off, post the details here and I will take a look through my copy of the BS.

You get the profiles from lots of places, here's one - https://www.ultraleds.co.uk/led-profiles.html#?Category0=LED+Profiles&search_return=all&Category1=Plaster-In+LED+Profiles

Unless you are fitting individually controllable lights then dimming (or not) is done at the circuit level not in the fitting. Most 230v spotlights, especially those with interchangeble lamps (e.g.GU10), won't have anything "inside" except the electrical connection and lamp socket. As has been said, dimmable or not, colour temp and beam angle etc are all lamp specs so can be changed with different lamps. Generally with fittings that have interchangebale lamps I would say just find the one that you like the look of the best and suits your room.

My builder used concrete screws - these https://www.screwfix.com/p/easydrive-tx-countersunk-concrete-screws-7-5-x-60mm-100-pack/3313h

So, I've tiled most of the wall now and am left with a narrow floor to ceiling strip of about 25mm (see pic) The majority of this gap will have the flat section of the tile trim so what should I use to stick the tile strips with? I'm assuming the standard tile adhesive won't stick to the metal trim so do I need something a bit more "sticky" like those stick like s**t type building adhesives?

You could try unscrewing the plastic bit attached the door front, sometimes manufacturers mould their name (or a component code) into parts but not always visible.

Just about to tile one wall in the downstairs loo with 300x100 wall tiles. It's plasterboard which has been emulsioned previously so I've sanded it with a power sander (using 80 grit paper) which hasn't removed the whole paint (it's at least 3 layers) but has started taking some of the top coat in places. I'm also going to score the whole area with a stanley knife in a criss cross pattern. Hopefully that should mean the tiles will stick OK. I'm using Weberfix Plus pre-mixed adhesive recommended by the tile supplier but I wondered whether dampening the area by wiping with a wet cloth will improve adhesion or not? If not, any other tips? Cheers