joth

My understanding from a friend that's a civil servant in the BEIS is this is pretty much exactly the aim of the scheme. There won't be mass-adoption of heat-pumps unless there's critical mass of installers nationally, and the public need to have confidence in their ability to design the systems, install them and support them. And not enough installers are investing in the training needed to do this without this incentive. RHI is clever economics that worked for PV and they're now applying here to, as while it is government funded, they're getting Joe Public to provide the upfront capital, effectively a loan, to provide installation bonuses to the MCS installer, that the government then pays off over 7 years

LOL to be clear, we tendered the work, signed a contract, and they've been working onsite since January (with a 3 month lockdown pause) so I think they've already very much got the deal. We're already over paying, with 20% VAT on the EWI just because of going through a main contractor; had we contracted this separately we'd be looking at just 5% VAT ... and now the £5k bung too doubles the potential savings. It would be tempting to think about, except I'm now busier than ever without thinking of taking this on (itself due to Covid cuts at my place of work). [I probably deserve to have my forum membership revoked for admitting any of this. Not very "self" build, am I... ]

Well we have 50% off meals out for August, so that's helpful! + VAT reduce to 5% on prepared meals , hotel accommodation, and theme parks + £5k voucher for insulation & energy saving measures (redeemable only via registered installers, so doubt I'll get this as we already tendered the work) + stamp duty removed for houses under £500k until March next year + various job creation schemes for under 24 year olds.

They distribute via a long of different plumbing merchants so recommend going there, and likely get discount off list price: " There are many in your area HBS Heating & Bathroom Supplies, Tucker French, Beggs & Partners, James Hargreaves are all independent plumbing & heating merchants, alternatively PlumbCity, Plumbase, City Plumbing Supplies, Wolseley or Graham Plumbers Merchants who are all national plumbing & heating merchant chains to name just a few." In the end it makes much more sense for me to purchase it via the guy installing the ASHP too, as that way I'll pay 5% VAT rather than 20%. Happily I'd already gone through all the details with OSO sales office, so when my ASHP guy contacted them directly they already knew the project and what I wanted so put him straight onto a preferred merchant who they knew would do a good prices and arrange delivery direct to site. All done via sales.uk@oso-hotwater.co.uk, super helpful folks. I'll of course withhold final judgement until its installed and working, but so far I'm quietly optimistic this will be spot on for us.

And not by coincidence, these are exactly two makes of car that are constantly in the local crime reports for getting stolen off of driveways. Seems pretty common around here for the big houses to have (at least) one of each so the organised crime units seem to treat them as "nick one, nick another free" opportunities. The BMW and range rover security is so bad you have to figure it's by design as this way they sell more from all the insurance claims.

Slightly different situation, but a near-neighbour installed a 14kW split system Ecodan and when it's driving the UFH he finds it can't modulate low enough so is constantly short-cycling, and only achieving COP of 2 or less. He's working on a claim under MCS to get it replaced as it's over specified for the property. So while oversizing is fine for heating a cylinder, also check it won't be too much for the heating circuit.

A colleague did a major renovation (the inspiration for own own project, in fact) this way: everything was open-book and indeed managed through BuilderTrend. Both aspects of this suited them very well, as they wanted a lot of control over design elements that could only be decided as it progressed, and having the app give full visibility of the process start to end, including what they wanted done each stage and how much it would cost before it happens. One snag was he (as client) had to take control of the "architect" / contract administrator role in the app to keep things moving at a reasonable pace. Fortunately his brother was the architect/contract admin so the trust was there to make this work. (No idea if the builder ever new this is what was going on). I know from our own project the 3-way builder-architect-client decisions can be painful. (But I find much worse the situation we've had once or twice where architect approves a change without looping us in, and then a month later we get a surprise bill for thousands on work changes we would have preferred having input into, or at least advanced warning of. BuilderTrend REALLY should solve that problem at source. I wanted to use it before we set out, and would definitely seek to make that a requirement of any future job like this). That said, no idea if it's because of my colleague's tastes, the fact they just weren't super cost-sensitive, or because of the area (London) or what, but their project did end up well over double the initial agreed budget. So while going open book gives visibility on price, it is not necessarily better for controlling it.

It's not the question you're asking, but quite related: make sure the toilet bowl you purchase is "low cistern" compatible. Unfortunately there's no standard marking to tell you this, but the bathroom sales guy (earning his fee) warned us that modern "whirlpool" style rimless bowls really need a bit more drop to get enough speed up to really work. (And then, they really work very well). Also, a higher cistern means you can leave the lid up and still get at the flush button (This is either a feature or a bug, depending on your outlook). Anyway these are the reasons we got pushed to 120cm cistern, and redesigning the boxing in to deal with it.

Agree, majority of our quotes are ex VAT and indeed handled via a main contractor so it would be very difficult for them not to pass through the VAT savings. The one wrinkle on those is where we've already personally put down deposits inc VAT (mvhr, windows, internal doors) we won't see that tax back. Had our contractor paid deposit and not yet billed us it would be a different story. I'm sat on numerous other quotes wanting a deposit (bathrooms, kitchen, ashp) so will hold off on those for another few days now. The main place we'll be going to consumer retailers is kitchen appliances (Curreys, JLP etc) so aggressive online price comparison could yield some results. We won't need those until November or so. And some fresh furniture in the January sales ? All that said, bet he won't drop it.

My local installer was happy to quote supply and install for the 8.5kW with matched Ecodan 300L tank. That was his default suggestion, in fact. In the end I switched it out for the OSO Geocoil tank which actually reduced the quote and also reduces standing heat losses.

Full VAT, full fat renovator here. Please, don't get my hopes up of yet another VAT saving we'll somehow manage, through extreme ingenuity, to maneuver ourselves out of [Current 30% of our way through the spend, having just shelled out 13% of our total spend in the last 24 hours...]

Panasonic have the PAW-FC-D15-1 at list price for £230 which I think is totally reasonable, if I can just find someone to supply one https://www.dysk.co.uk/wp-content/uploads/2019/06/Dysk-Panasonic-A2W-Price-List-2019.pdf

And even less if you have an export tariff, in which case you'd want to use the market spread - difference between average "buy" and "sell" prices. So about 10p/kWh On the other hand, the point here was batteries allow a system design where ASHP will maximize its contribution to DHW needs from the PV, rather than using the immersion, so allowing the COP of 3+ to come into effect, which does provide a little more economic up-side. Still, at this point anyone installing it is doing so for more than pure economic value alone. (Be it environmental, or the benefit of grid failure backup - which itself maybe an economic justification in these days of home working)

To be fair, this is "how much battery storage can I get for £13,000?" which if very different to "how could I usefully spend the £3000 I save by not going with a sunamp?". To the latter, I think 2x PylonTech US2000B plus an inverter and installation might be possible around £6-700/kWh? (And easy to add more storage in future as prices drop).

@davidc In the U.K they come with cooling disabled. Cooling can be enabled by adding a "coding resistor" Once again, @Dan F knows the products better than their own sales people.

^ all of which is to say, your question is a very good one and I'd also be interested to know if anyone has experience of this with the Vaillant too :-) But don't hold your breath waiting to find an installer that will give a straight answer!

AIUI this varies a lot based mst of all on the installer, rather than the manufacturer. Some will do it without batting an eyelid, some will insist "metering for usage" needs installing, some will tell you you're breaking the law and deserve to be put in jail if you enable it. RHI itself is now clear that colling is allowed, but the payments will only be made based on predicted heating use. (Or actual heating use, if they require you to do metering for usage) some manufacturers go to greater lengths than others to permanently disable cooling, so the above is based on ones where it's broadly possible. No idea where Vaillant sit on that spectrum. After going around this several times, my end tactic is to install it without cooling enabled, but make sure I'm with a manufacturer with plenty of track record of ppl being able to DIY enable is post-installation (specifically, Mitsubishi in my case)

Absolutely. I actually thought you were talking about self builders that only care about passing SAP and don't believe airtightness has any other value except box ticking. (IIRC someone was expressing this opinion on here just this week)

I had a heating/plumbing schematic drawn up last year that I'd like to redraw and adjust myself. Anyone got recommendations for a cheap (free) tool that's good for plumbing/pipework and control diagrams? I see lots of P&ID packages by no idea where to start Years ago I'd have used Visio so a nice replacement for that might be enough

This is rampant across the industry though? You hear of big developers failing the test (on the odd house actually tested) so the squirt sealant under all the skirtings so it passes. Then next day the carpet fitters arrive and cut the sealant all out again Honestly no idea how to avoid it really. Airtightness is so hard won and so easily lost, the homeowner can easily destroy it the day they move in without even realising they have.

Got it. To be honest the photo looked alien enough I didn't even try and understand what I'm looking at. The instruction manual is clear the element must have thermostat and emergency cut off, and should not be replaced with a different manufacturer's, so the fact the manufacturer does rate this 4.5kW one for use in this tank seemed like it should meet those requirements . Like you I can't see if from the photo though.

So long as you have a single contractor this is possible, but if you are employing the subs direct you need it to still be unoccupied the day each of them starts.

As I understand it this scheme is not administered by the HMRC but by the contractor(s) you use for the work. So long as you can convince them it is unoccupied the day they start, and it has been for 2 years, they can choose to charge the reduced rate. If you have multiple contractors you need to do this with each of them. There's no mechanism to "claim back" any overpaid VAT. Your tender docs should very clearly require this from the contractors If I'm not totally wrong, it means the SE work was full vat and can't be changed now, but the main contractor work is completely independent and not impacted by that. I'd be more concerned about the lack of hard evidence of it being unoccupied. Showing a builder your Google location history really doesn't prove a thing, I'm afraid. You have to prove *nobody* was living there, not just that you weren't.

1/ The immersion has it's own stat plus emergency cut out 2/ it has a built in thermostat for the indirect heat source, midway down the coil 3/ it has a pocket for optional heatpump thermistor above the coil (next to immersion pocket) https://osohotwater.co.uk/content/uploads/2018/10/OSO-DELTA-DGC-MANUAL-UK-142226-00A.pdf If the heatpump thermistor is used for "fine control" the standard stat effectively becomes a high limit cut off I also have a few DS18B20 I was thinking to attach to various pipework outlets for logging, but could perhaps be used for finer control too in future if really needed.

I checked, they recommend 4.5kW max, and that won't invalidate warranty https://www.oso-spares.co.uk/immersion-heaters/45-kw-immersion-with-2-x-4mm-cables