joth

While you have them on the phone, ask if they have any published guidance for how to future proof/prepare a new build or rewire for later installation of their system. ?

Right yes it was early in the morning and I not enough coffee yet. I realize now I'd already found the 4.8 figure last month and commented on that upthread, and indeed already done the PHPP experiment too. The new UK spec matches the one previously published on the vaillant.nl website so same findings hold: we'd save 1.5kWh/(m2.a) on PER so about 227kWh/a or £35/a having this ASHP vs the Panasonic. (And discount the Daikin as both uncredible, and no cooling), and a bit more ontop from having lower heat losses of the Sunamp. Add on top there's going to be a delay until Sunamp have tested this new heatpump to certify its use, plus installer availability is so limited, I am leaning towards whatever presents itself as the most trustworthy/reliable option but still open minded it could be this setup.

Looking through the COP figures I'm a little underwhelmed by it, tbh On the 7kW model I see A7/W35 COP of 2.8, which is actually lower than the A7/W55 score (2.9). The higher power units fair even worse at low flow temperatures (COP=2.4). Compared to the 4.52 on the Panasonic monobloc we've currently selected, I'm not sure if the improved DHW performance (with addition of a Sunamp) justifies this kind of hit in heating. EDIT: ignore all that. I was mixing up A-7/35 with A7/W35 due to very unfortunate word wrapping in their spec sheet. A7/W35 COP is 4.8 so much closer to what I expected! I'll put it through PHPP later and compare. Lower GWP is obviously nice idea. But the main issue I've had is exactly zero of the Vaillant installers will talk to me. The only returned calls/emails were to say we're out of their service area (by, like, 10miles). Many thanks again @Dan Feist for sharing this info though. You really got some better contacts there than my attempts managed!

Thanks! We've really cut corners with the main door, selecting the same internorm patio style door as we are using for the kitchen side door. Our front door is not visible from the street (on side of house, perpendicular to the road) and will eventually be covered by an external porch, so really seemed a waste of money getting a statement door. But seeing yours gives me serious doubts as this is exact look I originally had in mind!

@pocster is yours a RK door too? Mind sharing U-value and aprx cost? It looks lovely

Yes, I have some experience of a very simliar plot to what you're proposing, and we're able to park our car in the parallel-to-house position entering forward, reversing to get back out. Our car is about as long a production car as you can generally get in the UK (4.9m) so about the upper limit of what you'd need to consider. I'm not sure we may have a tad more width to swing in than the 3688 you are proposing, but there's a prickly hedge blocking part of it so we generally try and leave a clear margin around. I wouldn't choose this layout, especially if I was say doing the school run everyday (on a peak-time busy road) but for the occasional weekend trip we do it's fine Yes. Unless you have all-wheel steering (like Mercades added to their Vito vans to allow them to be used as black cabs) then the swing arc is very different forward vs back. We first tried reversing into the afore mentions spot and it simply doesn't work because the trailing swing arc neeeds to go through the party boundary hedge. Given the lenght of car, I'm extremely grateful I paid for reversing camera to get back out in reverse though. As it's reversing over a pedestrian footway with regular buggies and kids on bikes etc up and down it, and entirely blinded by two hedges, getting out of their single-handedly without a reverse camera would be quite dangerous. The planners may or may not care about this, given your case is a demolition and rebuild and I believe the limitations on reverse-out must already exist on it? I have no idea if they can/would enforce higher bar on parking reqs for a rebuild vs what's already there.

Excuse the ignorant question, but is the driver built into the unit pictured or is it a separate? Afaict the tridonic LEDs take 220V in so not sure what sort of driver you'd add. (Dimmer aside)

I hear that Virgin may refuse to use cable that they have not provided themselves. Of course, you could have them install N set-top boxes in one room and then move them to your own locations after they've gone, but still. What I did was request installation (on a rolling contract) and then one week later tried to cancel. This results in a call from a customer service agent fully incentivised to help retention. ? I explained I needed to do a pre-wire, and they arranged for an engineer to come around with plenty of spare cable which the gave me to pull through the walls during first fix. See

The motor in the fan is an inductive load and liable to damage a dimmer that is only designed for resistive or LED loads. In more practical terms, matching dimmers and LEDs is enough of a pain without making life harder adding more variables to the mix.

Err, are you saying the extractor fan is controlled by a dimmer switch? That's not a good idea at all

Not sure how much this was said in jest, but just FWIW achieving a good level of airtightness requires much more effort than choosing a build method and the crossing of the fingers.

The other thing to bear in mind is if you built enough generation to cover all your needs, you'll regularly have far too much excess you can't do anything useful with. At which point you'd perhaps want to install the grid connection anyway for export...

UKPN refused to allow a new supply head to go internally when I was getting quotes. They moved our meter to the garage in the end, as it was relocating an existing supply it could remain indoors, but if we'd gone for a new 3ph supply they said they'd only allow that to be fitted externally. (Probably would have gone down the GRP kiosk route)

Still planning on going with the quote we had on the Moralt, but haven't actually ordered it yet.

Thanks for sharing it. Quick comment that you appear to be using kW and kWh interchangeably, which makes the data hard to follow. Also of interest would be knowing the CoP achieved on the sample days, and the floor area of the space heated and target temperature the thermostat set to, to get an idea of the parameters it's working within.

At a rough approximation, if the mains supply pre-PV istall regularly hovers around 250V, would this likely be a warning sign for the PV inverter regularly hitting 253V and having to cut out? I only started logging voltage in the house a week ago, but I've not seen it drop to 240V at all, and it's regularly hitting 250V The DNO have approved 8kW G99, but I'm wondering if they saw this area is regularly overvoltage so figure there's no need to reinforce as the inverter will be regularly cutting out anyway.... I guess real question is what happens outside of winter. I see there's a really annoying failure mode here that if the inverter does cut out, it will stop dead any export meaning any dynamic loads (immersion divert or car charing) would also then cut out, which would allow the observed voltage to rise further. Whereas ideally you want to tackle the overvoltage by adding additional loads to pull it down and hence allow the inverter to re-engage.

Remember the PV won't generate much during the winter so you mac heating load calcs won't be much use for guiding how much solar to install. Presumably you don't have 3 phase mains supply? That gives you the option ofup to 12kW before needing the G99 application. If you are single phase and do make the application, put the max amount you might want to install on it (so 8kW), they are may come back saying only 6kW export is allowed or something in which case I'd probably aim for that. (while you can have more with an export limiting inverter, they cost more and will be another point of contention to resolve in the G99 application) If they grant 8kW you can always decide to install less than that. Not to mention the VAT savings?

Try the SEG league table: https://www.solar-trade.org.uk/resource-centre/advice-tips-for-households/smart-export-guarantee/ The battery FAQ there is fairly comprehensive and says that while the SEG does not oblige suppliers to pay anything for non renewable energy sources, currently none are putting additional limits on if you have battery storage.

For £350 definitely keep it. You can always ask your supplier for a single phase meter even if the DNO has provided a 3phase cutout, so having 3 phase supply strictly increases your options and doesn't remove any.

Just an idle thought about this - I wonder if they require the solar to be an MCS installation? Or if they'd accept some evidence it meets the requirements of MCS I don't see it mentioned as a requirement on the website, only thing it says is you "have solar". And while MCS is a requirement for the smart export gaurantee, this isn't really that

Ultimately you can do whatever your building inspector will sign off... However we have already experienced they'll approve one thing on paper then change their mind after you've installed it, so better safe than sorry. Our plans put AVV in the loft and an external open vent from the drain routed from the end of the main drain, up the outside of the house to the eves next to a drain pipe. My own simplified interpretation is that the regs require all horizontal drains to have a free flow of air through them, but this doesn't necessarily have to be through a stack pipe used internally in the house (or otherwise).

Let me rephrase that for you: “a ring final (also widely but incorrectly called a ring main)”, though why we don't just call them “rings” or “ring circuits”, as we do with radials, escapes me; a house will likely only contain final circuits and maybe the odd sub-main. Right. I'd go as far as say they're universally called Ring Mains by Joe public, so I intentionally kept with that terminology as it what was used in the OP

One other thing to note that I don't see mentioned on the linked pages is you can't convert a ring main (also called a ring final) to radial simply by disconnecting the final connection back into the consumer unit. All cabling used throughout the circuit also needs increasing from 2.5 to 4mm2 https://www.homebuilding.co.uk/electrics-cabling-circuits-and-switches/ (unless the circuit breaker is down rated to 24A) It's the cost savings of using smaller cable that is the reason for popularity of the ring main.

So the personal allowance hasn't really changed in 30 years, correcting for inflation: https://www.bankofengland.co.uk/monetary-policy/inflation/inflation-calculator

Yeah if you're using solid core runs, the patch panel is the place to convert to stranded cables. Ideally the solid cores then will never have to be touched or moved again and can last decades. Analogous to why in a lighting circuit you have a ceiling rose rather than drop T&E to the pendant, say