Dan F

Approaches I know of (none ideal IMO) are: 1) Manually switch Powerwall between modes based on Octupus pricing. 2) Use https://nureauwocket.com/Agile/ (includes handing over your Tesla credentials) 3) Code something using unofficial API https://github.com/vloschiavo/powerwall2. (you need to force reboot to make changes take affect though it seems) 4) Find a HA plugin that uses unofficial API. Please share anything else you might find. Clearly the issue with using something unsupported is that it can change and or go away if Tesla make changes..

How exactly do you plan to "link" it though, given Telsa don't document/support any offcial API? Using the unofficial API or some third-party app? We plan to install a battery sometime in the new year, but the inability to easily control the Powerwall programatically is really putting me off. That said, the Victron alternative is more expensive, more complex and takes up more room in the garage.

@pocster Do you plan to try to control it in any way, or just let it do it's own think and guess when to charge?

Also, remember that the power output varies based on outside temperature and flow temperature. So if possible get the datasheet and use the values on this rather than the "headline" number in the model name if possible when comparing with your requirements. By way of example a "7kW" ASHP I'm looking at is: - 7kW at 55C flow and -5C external temp. - 10kW at 35C flow and 2C external temp.

Sure. Here is a worked example using the tile we plan to use on all our ground floor. 1) Find, or be recommended an expensive product. Example: https://domusgroup.com/products/limestone. (around £98+VAT/m2) 2) Find a photo of the product and copy it's URL. Example: https://domusgroup.com/system/inspirations/images/b56/cc9/8f-/large/Limestone_DCLM_01_Honed_(2).jpg?1533201970 3) Go to Google Image Search https://www.google.com/imghp, click on the camera and past in the URL from step 2. 4) Skip over the Domus and pinterest search results and you'll discover the manufactuer is Cotto D'Este. https://www.cottodeste.com/collection/limestone (If you don't get any results, try again with other images) 5) Now seach for "Cotto D'Este Limestone" suppliers. 6) If you want to find an italian supplier, change you region settings in google search to give you results from italy (chrome will automatically translate anything, so no need to worry about language) 7) You now have lots of leads - https://tile.expert/en-gb/tile/cotto-deste/limestone - https://www.tilelook.com/en-GB/users/cotto-d-este/tiles/limestone-lime-stone-clay-30x60-honed - https://www.italian-bathrooms.co.uk/ - https://brandedtiles.co.uk/brands/cotto-deste/ - https://shop.orsolini.it/prodotti/pavimento-rivestimento-in-gres-porcellanato-effetto-pietra-limestone-clay_372693 - I even found it at 18 EUR, but i think they might be seconds and not have all finnishes. (https://www.edilsiani.com/negozio/pavimenti-e-rivestimenti/rivestimenti/limestone-clay-cotto-d-este-blazed/) 8 ) Find cheapest and negociate based on quantity. I'm on step 7, but a fair price seems to be £45+VAT. ?. Of course the same method applies for other suppliers/brands.. Be interested to know if anyone has used https://tile.expert/en-gb/ ?

We were recommended Domus; fairly big London based setup that markets to architects and interior designers. Prices are in the £95-100/m2 range for a very good quality 14mm limestone effect tile in 1200x600mm. Bit of googling later and becomes obvious that all Domus do is resell Italian tiles under their own brand for a profit. Google image search is great for working out who the actual manufacturer of products marketed in the U.K. actually is! Now I know the original brand, I'm able to find other resellers both here and in Europe and find the best price. Not ordered anything yet, but down to closer to £40-50 already, before requesting any discounts.

Found a quarzite mid-grey one for £39/m2 including delivery, going to request a sample Monday and will report back..

I don't have formal quotes for all options and the exact price depends on specific product variant, that's why I shared rough number and not specific. They aren't simply guesses. Tier/Norstone/WildStone all appear to be in the £58-68 range. The real stone cladding stone panel quote (for black state) was £44. The taylor maxell StonePanel was £86 (but may vary based on exact stone choice). The Taylor Maxwell is product is very good, 50mm deep and real chunks of stone.. whereas the wild-stone product, while it looks great online, seems to be simply formed/painted concrete.

https://www.burtonroofing.co.uk/cupa-r12-500-x-250mm-natural-roof-slates-holed.html £1.83 if you buy 1000+. I'm sure you can shop around though, or your roofer may have a trade account. The Del Prado price was what our roofer told us, not seen it personally. Also, I heard that quote a lot of people that use Cupa opt for the cheaper H range, which just requires more on-site grading apparently.

To give you an idea on price for 500x250mm "first" grade: - SSQ Del Prado was around £1.50. - SSQ Del Carmen around £2.25 - Cupa R12 around £1.75 Welsh slate, I was told was up at the £5 mark. The canadian slate is a good alternative for Welsh slate, but is more expensive than Spanish, at approx £2.50.

Two big spanish slate suppliers are are SSQ and Cupa. Take a look at their websites: https://www.cupapizarras.com/uk/ http://www.ssqgroup.com/ There a are a number of large national roofing merchants, one of which is burtonroofing.co.uk/, they are owned or partly-owned by Cupa so don't stock SSQ. I found them very helpful though when I called for some advice. https://europeanslate.co.uk/ is another supplier, but we didn't look at these. We really like the SSQ El Carmen, but decided to use Cupa R12 as it was cheaper and grey rather than black/blue, which we preffered.

I'm also looking at supplying from europe, as £60-85 m2 U.K price seem is quite high. Will let you know.. Also look at: https://www.realstonecladding.co.uk/ https://www.taylormaxwell.co.uk/

https://www.brick-clad.co.uk/ have got a good range. Other alternatives to Norstone are: - Tier Systems - Wild-Stone. - Cupa StonePanel

Just wondering why wool? It you want some natural/sustrainable and vapour permeable isn't something wood-fiber based potentially cheaper and also easier to work with?

Ours too. But in the intro, rather than the itemized part. To be fair the ublink ducting is needed for intake/exhaust as it's more flexible and will help ensure we can get these through joists. Although they did supply the same for MVHR<->Manifold internally too. For the internal ducting a initial 50m of a https://agix.fitt.com/ product has been delivered so far. Nothing to make me think that it's any worse than the Zehnder stuff, although it has come damaged..

We've had design by enhabit and happy with the service so far. They are also doing supply and commisioning (but not install). We also found them to be cheaper than Paul. Only thing we've noticed is that some of the ducting equipment is other brands and not just Zehnder, so may that be one way they keep their prices low. Not saying this is an issue though... (ublink + fitt) Design has be comprehensive and included flow-rates (based on building regs + PH), 3D design and drawings, interaction with frame desginer, advice on gaps needed below each door etc.

Do you need boiler and ASHP? Considered just ASHP? That's one option, you could also consider doing it via MVHR, just this approach will only work well if you have very low heating/cooling load. If you aslso using UFH and have high levels of insulation, then central cooing/heating via ASHP+MVHR is more practical. It's not really a case of what is the most current or practical thinking, but more about what is best fit for your build given your heating/cooling load, if you have ASHP/MVHR or not, and if you can insulate MVHR ducts or not. We are using ASHP and heating/ cooling will be indpendnealty controllable ground-floor UFH combined with first-floor MVHR duct heating/cooling.

I'm not an expert, but this is dealt with by the wall make up being vapour permeable. Typically the external board/membrae is something like: - https://mdfosb.com/en/medite/products/medite-vent - https://www.ecologicalbuildingsystems.com/product/solitex-fronta-humida This stops water getting in and let's vapour get out. A vented cavity is needed externally to allow this. At the same time, an internal airtight board/membrane stops air/vapour being tramsmitted from house to wall. - https://mdfosb.com/en/smartply/products/smartply-propassiv I think you are potentially imagining a problem, that is actually already been worked out?

If you increase specific capaicty to 204 Wh/K which is suggestion in PHPP for a concrete box, then not much changes No, why should it? Heating load is energy needed heat house on coldest day. The coldest day is winter is unlikely to have much sun heating the house. Are comparing 75/89mm internal studwork with (if you're lucky) some rockwool with 300mm external studwork full of celulose? Also consider that a 140mm external timber-frame wall with PIR does not perform nearly as well in terms of noise or decreement delay as a 30mm twin-stud wall with celouse. I don't think many people would agree with 50yr lifespan at all, lot of historic building are timber frame and timber frame is used very widely in a lot of place in the world.

I think the correct technical term for what you describe is "Specific Capacity" whhich is meansured in Wh/K. PHPP agrees with you that the higher the specific capacity of a constuction, the lower it's overall heating demand. If I take our PHPP and increase the specific capacity from 84 Wh/K (concrete slab + timber-frame) to 180 Wh/K (suggested value for a concrete walls too) this is what happens: - Heating demand goes down 5% - Heating load stays the same. - Overheating risk goes down by 15% We are dealing with overheating via use of external blinds so that a non-issue, and 5% reduction, in an already very low, heating demand wouldn't be enough to justify a concrete structure in my opinion anyway, given the sustainability and sound-insulating attributes of timber frame and warmcell alternative.

You do realise that there is a. bit of a contridiction in building a passive house out of concrete? Concrete production accounts for 8% of global Co2 emmisions, whereas a timber structure from a sustainable source actually stores carbon. So, your passive house might reduce your yearly carbon footprint, but to fully consider it's environmental impact you need to consider the build and it's materials too. There is a lot of useful information on this here: https://www.leti.london/

You would if it's the same person doing counter-battens and battens. In our case the roofer will be using BS5534 rooding battens, but the timber-frame supplier has used non-BS5534 for the counter-battens. This isn't a major issue in my view, but apparently the latest revision of BS5534 as well as the most warranty providers now require BS5534 battens for coutner-battens too.

Do you have a reference for this? NHBC/Permier warranties specifiy BS5534 as a requirement for counter-battens, so I suspect this may have been introduced in the last revision of BS5534.

And you need a generator for when you don't have enough PV to meet demand.

Our order went in 31st July and all windows/sliders are due on site this Thursday (6-7 weeks total). We are starting to get a bit concerned about everything else we need to order which will likely come from europe though. Don't really want toilets stuck on the back of a HGV backed up in customs ?