joth

To be charitable, they might have been trying to say it needs to be installed to MCS or equivalent standards to be valid under permitted development. But more likely it's exactly as you suspect.

Ha yes I meant to add, I assumed they only want cold input as they can't assume hot supply is safe to drink. But then, outside of the kitchen the cold supply traditionally isn't safe to drink either so if that's the reason it'd be helpful to state explicitly rather than rely on a hot vs cold assumption. If we have pressurised UVC then as I understand it the WRAS regulations require it to be just as good quality as the mains cold supply so this issue wouldn't be a worry. (Plus the boiler is literally boiling it so double protection) We're in a very hard water area so planning whole house softener, so yes I should just ignore the built in filters. Thanks.

This is interesting to know. Looks like Grohe claim 15W standby so 50% higher than the Quooker combi. They also show the tank being filled from the cold supply, any idea if there's any technical reason it couldn't be filled from the DHW supply? This would reduce the time it takes for hot water to come through the pipe when running the kitchen hot tap, and also reduce the amount of work the boiler has to do to get the contents back up to boiling. Some reviews say the filters are one of the more expensive to replace, haven't researched that side much yet.

That's an interesting option. I've been looking at the Quooker Combi for exactly this purpose -- I don't want a secondary return in the kitchen as it's fairly random when we want hot water there, and open plan so can't easily use motion sensor, so would mean running the circulation pretty much constantly to be any benefit. (Bathrooms are much more predictable and reactable, in comparison). The Quooker combi install manual only supports a cold-water only supply mode, i.e. using it means 100% of kitchen hot water is coming from the cold supply quooker element heater tank which is suboptimal as we'll have ASHP, and it adds a risk of running out too is using a lot. I was thinking to try feeding the combi tank from the DHW water supply and just "see what happens", but going with the GROHE Red that explicitly supports it might be a better idea. (It does mean 99ºC water rather than 100ºC though... LOL) I can't find a standby heat-loss claim for the GROHE Red, it just says it's 10¢ per day at German electricity prices, which I think works out about (0.33kWh/24 hours=) 13W so similar but just a bit more than the Quooker claimed 10W

Refrigeration change is the single biggest technology mitigation to climate change on drowdown so it's likely we'll see a number of changes in heatpump tech in coming years. https://www.drawdown.org/solutions-summary-by-rank My mind does spin a bit at using CO2 to reduce GWP but it does make sense. I imagine a monobloc ASHP has much less GWP impact than any split systems so I won't let this dominate my decision process. Being able to bring sunamp back into the mix as a viable option is of some interest, except I finally got back numbers for the heatloss of a 300L tank with 100mm of insulation and it's really not that much worse than a sunamp Uniq12 -- 1.3 vs 0.9 kWh/day. If we keep the cylinder at 50°C and don't have it fully charged all the time I think we might actually achieve lower heat loss with the cylinder than with the sunamp (nice thing with the mixergy tank is comprehensive feedback on how much charge it's holding, vs none on the sunamp). Removing heat loss from the equation, it comes to cost and reliability vs space; as we have enough space for the cylinder I think the decision will be made for me.

Could I ask who did you use for supply + fit?

Actually Internorm you have more flexibility than most of the quality 3G manfs, as you can choose from at least Ecohaus, Aspect Windows, and AT-Eco (that's just the 3 UK supplier/installers I know of). For most manf. you either order direct from the factory of via a single UK importer. I take it you're after a quote from a different manufacturer though, rather than a second quote from a different supplier of the same products? Aside from the ones ProDave mentioned, we also looked at Gaulhofer (would have been preferred choice if our PHPP consultant could have made the numbers work), Green Building store, and Viking Window AS

The question breaks down into 3 parts - choice of manufacturer, supplier, and of installer. While these are related, you do have some flexibility within them. We found it easiest to look at the manufacturers and products first, from a performance and aesthetic point of view, and choices of supplier largely follows from that. We're doing what we can to have our (passive house experienced) main contractor do the install, for the exact concerns NSS mentions.

In case it's not fully obvious, the efergy is a cloud connected product, so while it allows it to work from anywhere, it means it's entirely dependent on your internet connection being up, and the company surviving long enough to keep their server working, and they can change the annual billing model at any time. This may be just fine trade off, but worth being actively conscious of. (Basically this is the flip side of the SageGlass app's "local-only" mode of working) EDIT to add the above applies to their 'engage' and 'efergy pro' devices. Looks like there's an "E2 Classic" that is local only, with option to download via USB.

Isn't' 100L fairly large for a buffer tank? My guy recommended 25L. Sounds a good idea, might do this even if it's not wired in initially.

I've also been thinking about this need for a single "boosted" zone (study, or elderly guest bedroom) but it requires not one actuator on the manifold for that loop, but to install the other N-1 (so 8 in @vivienz's case above) actuators for all the loops you want to shut off when running the single boosted zone.... Which adds quite some complexity and cost to a otherwise simple idea. As our UFH is only downstairs I think we'll start with no actuators and run it as one zone, see how it goes.

One benefit of getting someone else to do the EWI insulation is they can 5% VAT rate it (materials and labour) -- so long as they're not doing it as part of a larger project.

Was that supply only, or supply & install? And which aspect had the issues? Thanks

Do you want the kitchen cold water to be colder than room temperature without running the tap? If so, you may want to run the pipe from plant room to kitchen under the EPS too. Trade off of more penetrations in the membranes vs longer time running the tap to get cold -- so more of an issue if you have a long distance from plant rm to kitchen

I'm guessing this flow rate has deteriorated due to dirt/sludge in the system, so another tack maybe to get the system cleaned? Another thought: is this with radiators or zoned UFH? As an experiment try turning every room up to max temperature on the TRV/room stat and see if it goes away. It maybe that if you're only trying to heat one room there's not enough emitter capacity to get the necessary flow?

I did some digging into this over here: As best I can find, for domestic 3 phase meters will report the net-exporting state (within any given moment in time / 1Wh meter bucket), not the per-phase import/export state. This seems fairly well specified in the SMETS2 polyphase meter spec Part C, although as no one is installing polyphase SMETS2 meters yet so it'll be up to your own experimentation to confirm that on any other 3ph meters. Looks like @AliG has happily confirmed his A1140 import meter records records net usage across the phases- this is very helpful to know. Whatever you decide, you might as well have the DNO install 3 phase supply to the meter head/cut out. You're then perfectly entitled to only request a single phase meter is installed and used off of that, but it'll give you a much easier upgrade path if you decide the 3ph is useful in future.

Of all the risks I think the most likely to hit is the cloud service just packs up and shuts down leaving the smart device dumber than a dumb device. Latest example: https://www.theverge.com/2019/9/6/20853671/best-buy-connect-insignia-smart-plug-wifi-freezer-mobile-app-shutdown-november-6

Yes very good point -- this is looking at my final point from the other angle: if the damage done is in the new reduction in renewable energy generation (not the financial benefit thereof) then yes the applicant can mitigate that entirely themselves, no need for export sharing. Which could lead to an interesting eventual approval with a perpetual condition that XX kWh of solar generation remain on the extended property.

Some interesting points looking through this. - The legal basis for a right to light comes from the Prescription Act 1832 and was for "the beneficial use of the building for any ordinary purpose for which it was adapted upheld", and upheld to show a Greenhouse is an ordinary purpose and requires a higher degree of light (and warmth) from the sun. Which is an extremely good analogue for solar panels: growing your own food is effectively small scale energy harvesting, as food is energy. - As more solar PV is installed, this is increasingly provable to be an "ordinary purpose" of a building / property - speculation: with a future framework for local area "generated energy sharing" (as some countries already have) I wonder if a reasonable compromise could be reached in civil law where the infringed party instead accepts a perpetual "right" to capture an equivalent degree of sunlight on the planning applicant's land. This would ordinarily be fed into the grid under the applicant's meter/tariff, but if in future it's possible to assign it to the benefit of the infringed neighbour then perhaps this would be a amicable compromise.

Kitchen designers like white / very light worktops as they reflect back out the light of the spotlights pointing down at it and make the whole area so much lighter. We want a very dark worktop but our designer did warn about this. I had been thinking dark floor and work surface, wall and units all lighter, but now pondering the floor needs to by brighter too. Too many interconnected choices!

Thinking out loud, they might have been referring to the UFH actually causing the movement which might result in some creaking, rather than breaking. I imagine this would be more likely if you have a higher heat output, meaning stuff near the UFH pipes will heat quicker than stuff further away and the whole lot creak a bit as it takes up the difference in these rates. Pondering further... it is plausible some folks might have some expectation they can mostly leave upstairs heating 'off' but give it a high temp blast before bed time or first thing in morning. Generally in a well insulated home you'd not going to want to use it that way at all. On this basis, UFH actually makes more sense than radiators, as the latter really have to be used on a high temperature, and all the higher temperature flow pipes (especially if un-lagged) leading to the radiators are a bugger for causing joist creaking even in a traditional built house (come over to our current house if you want a demo). [/speculation]

We're also planning ASHP + 300L for 2 people, but a 4 bed house and wanted enough for having guests over etc too. Also we're having 8kW of PV so want the capacity to use the UVC to store heat across days of intermittent solar generation.

Yep, If I was starting again now, I might think more about using a traditional block and brick construction, as agree with others that timber import is probably something at higher risk of disruption. (Given we're doing a renovation of a brick house, keeping with existing would have had some technical benefits too) comment: you don't need to keep funds outside the UK to hold them in USD. And if you're not already holding USD, based on historical data now would be a bad time to buy them. Paying foreign supplier directly would probably make you the importer, and all the headaches that go with it? I know people do that to save money on exotic cars, but even in times of stability all the paperwork involved would put me right off it. I think building a house is challenging enough without a side line in FX trading, currency hedging or import/export global logistics ? (Looking at it another way might be: If you're experienced in and good at and enjoy this stuff you'll probably do it anyway regardless of brexit, and if you're not you probably stand to make more losses over it at a time of instability than the big boys that do this for living.)

@Dan Feist very similar situation as you, and I've gone for option (i) ASHP + UVC Sunamp was very alluring but the high temp requirement just put me off too much. I have no doubt it could be made to work, but it puts more constraints on the rest of the ASHP system design and this was already an area of massive scope creep in our project. In a few years maybe they'll have nailed an elegant ASHP integration, and maybe there'll be some other players offering some competition and choice in PCM heat batteries as it's an idea I really want to widely succeed. Sorry, that's not very helpful in context of the OP!

@jack self installed a Loxone system and has good experience with it by all accounts. You can search the forum for his various helpful insights into it, but may have more thoughts to add specifically on heating & climate control. It's also my currently preferred option, for an install not totally dissimilar to yours. We like the aesthetics of their switches over any other smart switch options and the built in temperature and humidity sensors are a bonus. To manage costs I'll only use them in living and bedrooms, at least initially, and put cheap retractive switches everywhere else. Radially wiring means I can upgrade then in future if needed. I'll use it for lighting, heating, cooling and shading control. I looked into their music, power monitoring add weather forecasting, but think I might control those in home assistant instead. These are not critical services, I want to keep Loxone for the critical BMS only, and remain understable e.g. to a new owner if we eventually sold the house with it still in (reversionary rights, as I think you put it?) Their music server is so lo-fi it beggers belief the price tag they put on it. This is symptomatic of the main reservation I have with the to be honest: in recent years their position has moved towards locked in maintenance through certified installers and new products have spread them over more and more market segments with more lock in through proprietary protocols and integrations rather than focus on the core competency of making their controller work perflectly with the market leaders for each other device type (Sonos streaming, Philips smart bulbs, KNX or WiFi weather stations, etc..) At first I genuinely thought their smarthome connected BBQ thermometer press release was an April fools joke. Hence I'm going into this cognisant that they may not be around forever and there's a chance it all might have to be replaced at some future point, again radially wiring the lighting is key to my comfort in selecting them. If I wasn't using them for lighting comtrol, the dependency would be constrained to the plant room.