Dan F

I need to check to confirm this, but I'm 95% certain the Tesla Gateway levages the vector-sum metering to effectively charge the battery from all three phases! Potentially, but you'd need to make sure that whatever strings you've used on the roof will also work with the three-phase. If you might want to switch you should plan your strings to allow for both options. We did this and actually have three seperate strings on the roof, but currently two of these are connected in series (in the garage next to the inverter) for 3-phase inverter.

Few things: - Have also future-proofed by taking 3-phases to main consumer unit? I would if I were you, else future 3-phase car charger(s) could impact how many amps you left on your single house phase. If main consumer unit has at least enough cores cabled, then you can easily switch to using multiple phases in the house if you need to. - If you use a 3-phase inverter you wouldn't be throwing away anything due to vector-sum metering. If you are generating 2kW on each phase, and consuming 6kW on phase 1 then that is does not count as import nor export. A lot of people, including some solar installers, don't actually understand how this works! - Only disadvanage with using 3-phase inverter is should you loose power, you'd need 3 batteries (one on each phase) to using your PV off-grid, rather than just one. But given power if never off for any extended time in the U.K. this wasn't an issue for me really.

I've checked and we have some ESBA ARA659's on-site ready to be installed. There are the 1-10v proportional version of the same valve. I assume these were chosen as I'd mentioned Loxone. But, digging into the Vaillant installation guides it seems that Vailant also supports multiple "mixed circuits" with different flow temperatures and weather compensation curves, so I think I'd better get these switched out to 230v SPDT versions so that this can all be setup up and and commisioned as part of the ASHP install. If it works well and adjusts the ASHP flow temp based on the circuits which are on/off and their target temperatures then they'll be no reason to do anything myself.

What valves are you using and are these controlled from Ecodan wiring center or via Loxone? Do these values take a temperature set-point or there is also a temperature sensor and the fancoild feed and an feedback loop used? We have 25L buffer by the looks of it. That would be good, assuming it supported. If the API allows for adjusting set-point as well you could have 4 modes: - Cooling 5C (UFH + fancoil) - Cooling 15C (UFH) - Heating 30C (UFH) - Heating 40-55C (UFH + fancoil)

I would assume so, how as would you do it? That's what our setup will look like; approx 17C for UFH and 7C for Comfopost is what we had panned. @joth Are these temperatures fixed in your setup or can you adjust them, based on for example the relative humidy? I haven't got it set up just yet, but I was thinking it might be good (if not slightly unnnecesary maybe) to be able to adjust the UFH/ComfoPost temperatures based on RH and/or how much cooling is required. You could then potentially adjust the ASHP set-point (between say 5C and 15C) based on the UFH/Comfopost temperatures and if ComfoPost is/isn't enabled. Farily non-trivial, and probably won't initially commison it with this inteligence, but given the ComfoPost will be used rarely it would make sense from a COP standpoint to use a higher ASHP set-point when it's not in used. I still need to explore exactly what the vaillant EEBUS interface does/doesn't support though, to understand how easier this would be. The only disadvantage of this approach is that on enabling comfopost/fancoil, you'd have a delay before they are effective while the buffer is cooled to 5C.

That's what the ComfoPost I refer to is. But rather than an air-con it uses cold water from your ASHP. https://www.zehnder.co.uk/comfopost-range

Give @joth's post on bedroom overheating in spring a read.. then you might change you mind ? Some people do report bedrooms being 19C vs. 21C in the winter. We don't think this will be a concern for us, but the Comopost will allow us to add a very small amount of supplementry heating if it's ever required.

How well did this work in practice, did you end up blowing air in from the plant room? We have a drying cupboard that backs onto the plant room with a MVHR extract above. In fact, the 300L UVC, which is about to be installled in the plant room, is right behind the drying cupboard. What I'm trying to work out is how much of this rear wall to replace with slats/grille: - If I just put a largish grille at the top then it will probably draw fairly warm air through the grille but not much of it will go past the clothes, which doesn't seem like a good idea. - If I just put a largish grille at the bottom then there is a chance that the primary ariflow will be from under the plant room door -> grille without picking up that much heat from UVC. - Alternatively, I could try to open up as much of the wall as possible replacing with wooden slata of some sort for aesthetics. This would make it a lot more like a traditional airing cupboard.

We have fairly large overhangs, high levels of insulation and airtightness and external blinds on most windows which will be automated by Loxone. So our calculations might give you a good idea: Cooling Load: 335W Cooling Load (no blinds): 1.3kW Cooling Output UFH (GF Only): 3.6kW. (UFH circuit @ 17C) Cooling Output MVHR (FF Only): 1.1kW. I think that 1.1kW may be based on the same 17C though, as the Comfopost datasheet suggests a cooling output of 2.1kW for 190m3/h with flow temp from ASHP of 7C. Given these numbers, MVHR cooling for us was a no brainer and fancoil/AC was clearly not required.

We're not in yet ? . Are you using ASHP, if you are would you not look at using fancoils rather then indpendant AC units? Seems a shame to use split A/C on a new build. The MVHR approach will only work well if your cooling demand is already low, and it's just to ensure bedrooms aren't few degress warmer. I can't remember, fif you have any cooling demand numbers to see how effective this would/wouldn't be?

I'm considering one of these two options for a garden room: - https://www.partel.co.uk/products/lunos-ventilation-with-heat-recovery - https://www.bpcventilation.com/vent-axia-hr100 Still need to look into details and costs though.

Agree with @Temp It's all up on the government website if you take a look. The definition of "designed as a dwelling" includes the requirement for planning. See: https://www.gov.uk/guidance/buildings-and-construction-vat-notice-708#section3 This same page also says the following, which suggests a seperate electircal supply isn't a must.

Do you have planning? Does planning refer to it as a seperate dwelling or as an extension/annexe?

Sorry, this is the correct link: https://www.engineeringtoolbox.com/water-supply-system-design-d_2157.html

Need to consider that plastic pipes have a smaller internal bore. We used 16mm for showers (13.6mm internal i think). Ideally you'd calculate pipe size based on required flow rates and lengths, attempting to use minimum possible diameters for hot to avoid wait times and heat loss. 15mm over 2m is very different to 15mm over 20m. I found this useful: https://www.engineeringtoolbox.com/amp/hot-water-heating-system-design-application-d_2155.html

Are you installing yourself? Our tiler is cutting on-site and installing these same 6mm large format tiles. From talking to him these large tiles also have somewhat tricky installation procedure which is more complex than standard tiles and requires a vibration tool to avoid trapped air etc.

The Powerwall 2 has always had 13.5kWh capacity! Telsa state a 100% depth of discharge.

Our original plan was: - 3-phase to garage to i) allow 12.5kW PV inverter ii) support future 3-phase car chargers. - 1-phase to house because i) 100A for the house was going to be plenty ii) it would simplify wiring in house iii) it would make backup from a powerwall easier. BUT, I then thought about what would happen if we wanted 2 x 22kW 3-phase car chargers in 10 years time and that changed things. Each 22kW 3-phase charger pulls 32A from all phases. This means that if we were to ever install 2 of these, our single-phase connection to the house would only support 32A at the same time as car chargers, which clearly isn't enough. Given this we've put a 5-core armoured cable in from garage to plant room so that even if we only use 1-phase now, we have the option to split house loads over 3-phases so that 2x22kW chargers could be supported in the future.

You could leave 20mm on cill, and 45mm on frame couldn't you? Your cill would still be as deep as it would have been with aluclad.

Can't you just sit windows further back inside the frame? Either that, or get the aluclad windows and paint them in "uPVC white" ?

Not sure as not done it. But one way of getting closer to direct is by going via an italian retailer. The italian retailers work on much lower margins then in U.K.

Good job you don't have a minibar!

0.46kWh/min I think. Which would mean your 2.4kWh shower earlier today was about 5.3 minutes? https://www.omnicalculator.com/physics/specific-heat?c=GBP&v=equation:0,c:4181.3!jkgk,substance:1543850775,m:18!kg,T:22!C

Seems so, £216 here https://www.flir.co.uk/products/flir-one-gen-3/?model=435-0005-02 . I'm sure the FLIR ones were much more expensive when I looked at potentially getting one of these a couple of months ago.

We started out planning for a 60cm oven, a 45cm steam oven and a 19cm warming drawer. But given a microwave was a requirement we've ended up with 60cm oven, 45cm steam-oven, 45cm combi-microwave and a 29cm warming drawer. We didn't want/need a combi-microware.. but a basic microwaves wouldn't have matched ? What suprised me is that as soon as you go beyond the standard sized fridge the price goes crazy! How can the a Siemens 603mm fridge can cost £5,400 when the 560mm version costs £1,600 RRP!