ragg987

@ProDave, if we accept that the MCS premium vs a DIY install is £2,000, then this premium has a payback of about 7 to 8 years based on a south-facing 4kWp installation. From that point you are making £280 per year. (Numbers not adjusted for inflation or cost of capital.) Plus it frees the stressed and busy self-builder 2 mandays to get on with more value-add activities. Half-full. IMHO.

I would say you need to revisit some fundamentals as per the comments above. Q1: if you have mains gas boiler why add an ASHP. Waste of money you cannot recover the extra capital. I posted some examples on this forum. I would stick with gas. However, if you add a PV system then it swings in favour of ASHP over gas. Q2: Why 15 or 18kW from your system boiler? We have 6 people and manage with a 7kW ASHP and 300l DHW. Our space heating load is higher than yours at about 3 to 3.5kW. Q3: Why have a water softener in-line with the UFH / heating circuit? The heating circuit is normally closed-loop so never needs fresh water after the intial fill. Just add inhibitor. Water softener is then reserved for all other uses apart from drinking.

Having moved into our dream in Oct 2016 I am now turning my mind to regular maintenance needs - what is essential / planned and what can be left to fix when it breaks? My initial thoughts... ASHP comes with a 5 year warranty, and there is a list of checks in the manual e.g. electrical, pressure, valves etc. Would I benefit from an annual inspection? I cleaned out the in-line strainer after 1 year, it had a layer of very fine grey powder in it. Filled with Sentinel X100 soon after commissioning. UVC tundish are visible and I can check for drips periodically - anything else? UFH? Just been keeping an eye on water pressure, I spotted a pressure drop in Dec and found a small leak, fixed. Water softener has a Clack valve, which can display error codes. inclined to run it until I get an error? MVHR I have been checking / replacing air filters and washed out the heat exchanger last summer. Solar PV and inverter. Apart from checking for mould on panels, anything else? Structure - MBC timberframe and ICF basement? Boiling tap, check tundish and change filter. External finishes are designed to be as low maintenance as possible, so don't think anything is required here other than keeping an eye out for damage. Render on board, brick slips, Lindab steel guttering and downpipes, Al clad windows, clay roof tiles, Cembonit through-coloured soffits and fascias, untreated Canadian western red cedar, steel garage doors, block paving. We also have some raised beds made from timber (i.e. modern railway sleepers). Inclined to leave them until they fall apart?

Some people advocate splitting your panels East and West to lengthen the time you have solar energy. Whilst true, your annual output will drop quite a lot. If memory serves something like 20%. So if, like us, you can use most of what you generate then go south facing.

Our in roof system, fitted and registered, cost £6k. This was about 2 years ago, prices have dropped since. 97% is the annual average. Our background load takes care of a bit, we try and run washers in the daytime, I time the ASHP to heat water in the daytime, in summer when we generate more I switch the ASHP off. And finally, the immersun diverts any excess to our 300l DHW. The bulk of the 3% we export is on long summer days when we have a tank full of hot water and nothing to soak up the excess.

As a reference, our community wi-fi charge £35 per month unlimited. 80Mbps down, 30Mbps up. Only down-side of their implementation is they treat the whole network as a large corporate, and each subscriber is thus double-NAT'ed to the outside world. So best suited to access from home to outside, not suitable for use other way (e.g. my own web server).

All good points, an additional factor is that roof integrated panels reduce the surface area to be tiled so there is a small saving here too In our case, 4kWp south facing with ASHP and immersun to divert to DHW. 2017 generation was 4MWh, measured export 128kWh. So we are consuming 97% of what we generate. I estimate our return from the PV is around £600 per year, less than half of which is from FiT and Generation subsidies. Based on our electricity costing 12p per unit.

Should add, build insurance we had specifically allowed for this scenario so it was not at their discretion. Self build zone.

Our BC inspector said it was quite normal for self builders to move on prior to sign off. Not sure about the legality, was a case of JDI, though I did tell various parties like self build mortgage, build insurance, council.

We moved in prior to BC sign off. Our build insurance covered us for this, our council did not query anything and were fine to register us for council tax from move in date, on an "emergency" council tax band until it had been properly valuated. Risk was that contents were not insured. Also we were unable to get onto a domestic mortgage or insurance policy until BC sign off.

Looks like you do not directly enter the window orientation, but use the data from the linked PVWatts calculator to reflect that the solar energy is reduced if the orientation is not true south. Enter your postcode on the website linked in the spreadsheet and go from there.

Sorry to hear, but to check... Where does this requirement come from? We have 22mm engineered oak and I would say heat transferrance is not an issue. In one room we have a very large and thick persian rug over the 22mm flooring and that room also heats well. I doubt if there will be a massive difference in heat transfer between 15mm and 22mm, I would say more important is getting a good bond to the screed and minimising voids and air pockets.

Talk to BPC. Great prices and they offer units from a few suppliers, they will also size and provide layouts for you. I talked to a few manufacturers prior to discovering BPC (a recommendation from either this forum or ebuild) - that was a complete waste of my time.

Our claim for a stand alone hot water tap was accepted.

I should add, one area where prices are lower is in optimizers like Solaredge and Tigo. If your array has local variations then these will help squeeze every last drop from your investment - e.g. if you have partial shading from a tree or roof-ridge, or perhaps your array is split into multiple locations and orientations.

Not comparing like with like - "install it yourself" is only free if your time is worth no money. If you are working to pay the bills then this is not necessarily the case, I had limited time during our build and so decided to focus it on where I could add most value. E.g. procurement where I could easily under-cut my builder for most materials.

Am not aware on any major breakthroughs recently, though Tesla (and others) have talked about the roof tiles becoming the panels. When I looked at this about 2 years ago, high yield = high cost of panels and the break-even point went up from about 8-10 years with a basic / cheap-as-chips system to over 12 years with the high-yield panels. Assuming professionally installed and FIT registered. So went with cheap 250Wp per panel to give 4kWp in total and paired it with an Immersun to divert to DHW. We also try and tune our living to take advantage of PV - e.g. running washing loads or ASHP. I went with roof-integrated fit which not only gives a nicer appearance, but also saved me money on tiling. Battery storage is horribly expensive right now and I don't see how it could pay back. More cost-effective to either use DHW to store excess or to export to the grid (I see the grid as a a large "battery" in this sense). Of course this will change as electric cars come to the fore and there is better integration between car battery and the grid. I suspect this is the way forward rather than stand-alone battery just for local storage. But of course will also depend on your use-case e.g. if you drive to work in your electric car then you have lost the opportunity to charge the car battery from excess solar.

Based on brand / reputation, Paul units are near the front (as I understand it). Quite a lot more expensive than some of the others. We ended up with an Airflow unit - built like a tank, so far so good (1.5 years in). But as per @le-cerveau, "the best" will depend on your needs and budget.

My experience with the ukecc was very positive. They dealt with their German counterparts after a faulty item that the German supplier refused to deal with. From a refusal came an offer of a repair which I rejected and eventually came a full refund. It all took many months.

Yes to vat on delivery for materials provided on same invoice. Separate invoice showing delivery only is a no-no. As per guidelines accompanying the form.

Doubt you could get a toilet and sink more compact that this. If you could fit a sliding or bi-fold door then the room could be tiny. https://www.ukbathroomstore.co.uk/aquarius-combined-spacesaver-wc-toilet-and-basin-aqsswc And it saves time too (at least for men) - wash your hands WHILE have a p**s.

Looking good, I'm sure you owe yourself a big congratulatory drink prior to the new year. First fix next? Make sure you get your ideas on lights, saintaryware etc together during the hols (if you haven't already), once your electrician and plumber start it can get pretty full-on.

If you use a dehumidifier make sure the bucket has a sealed and tight lid, else you will be trying to dry the water in the bucket. Better still hose to outside.

Preaching to the converted here. She would be the first to admit that logic is not her strength. BTW she has a 1.2l car that punches out 120bhp. Pretty impressive, I think back to a golf GTi I once owned that pushed out an impressive 118bhp. Them were the days...

I used an old fashioned air hygrometer purchased off eBay. It can be calibrated on site using salt water, then selaed on to the floor and left for a day or two to stabilise. @Ian is right in that you need to reduce humidity in the room to achieve drying. Heat helps in that it redices the relative humidity in the air, but you must extract that moist air else you risk it condensing and you have not gone forward. An advantage with the MVHR method I used is that the return air is dry compared to extract air. The MVHR drain pipe was full of water for a period.