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Hello buildhub residents. My first post here. I'm self-building a passive house in East Anglia and I'm looking at heating, DWH and potentially cooling solutions. My question is this - a load of companies seem to manufacture units that are either multi-split of mini VRF and have A2A refrigerant inverters available with a hydrobox for DWH (that's my reading of the marketing docs, please correct me if I've misunderstood the technology) But NONE OF THEM are available in the UK it seems (I hope I'm wrong, but I've called them and nobody knows anything about these units here). Does anyone have a good sense of why they're ether not bothering with the UK market, or why they're unable to get them licensed here? Maybe something to do with the distortions created by the Boiler Upgrade Scheme? The list has most of the big guys one it: Mitsubishi PXZ series - see around page 25 of this pdf here: https://kokotasgroup.gr/entypa/pdf/FULL_PRODUCT_HEATING_WEB--281-29_6166.pdf Samsung EHS TDM Plus Climatehub - https://samsung-climatesolutions.com/en-gb/b2c/our-solutions/home/heat-pump-solutions/heating-cooling/tdm-plus.html Daikin Multi Plus - https://www.daikin.ie/en_gb/product-group/air-to-air-heat-pumps/multiplus.html Panasonic Aquarea Ecoflex - https://www.aircon.panasonic.eu/IE_en/happening/aquarea-ecoflex/ LG Multi-V compact with Hydro kit - probably too big for my house, but anyway https://images.b2bmkt.lge.com/Web/LGElectronics/%7Bc5c4ca24-a96c-4aed-9cc9-97e1f6dbabf2%7D_2023_4Q_White_paper_Hydro_Kit_Low.pdf? ArgoClima iseries split - https://www.keaneenvironmental.ie/argoclima/iseries-split-pump/ Midea CirQHP- https://www.prnewswire.com/news-releases/midea-comes-to-ish-frankfurt-2023-with-its-latest-water-and-space-heating-solutions-301774592.html And yet - nothing available in the UK....

Anyone had experience with sizing A2A heat pumps (ie. Mini/multi splits) for heating loads? Have had a few quotes for fitting out our house now, and sizes from contractors have varied quite a bit. I’ve tried my best to approximate heat loss requirements using MCS heat pump sheet, as well as Jeremy’s sheet from the forum, and approximating existing radiator input. Often coming out with significantly lower numbers than any of the contractors. A couple examples: (House is detached chalet bungalow from late 90s, brick with filled cavity walls on GF, timber frame with 50-100mm insulation on FF. Located in South East.) Our lounge is a 25m2 room with 3 external walls and decent amount of glazing. MCS calc indicates probably 2kw losses, radiators (3) seem to add up to about 2.2kw. Contractors suggesting a 3.5Kw or 5Kw wall unit. Seems like 2.5Kw at most would be sufficient?? Looking to do ducted to 3 bedrooms upstairs, one about 20m2 and the others both 12-14m2. MCS seems to be about 1.2kw for the big one and 500-700w for the other two. Contractors wanted to do a separate 3.5Kw unit for each bedroom, and one contractor said 5Kw for the large bedroom. I am thinking we could get away with a single 3.5Kw unit ducted to all 3 rooms! (Daikin even does a plenum with motorised dampers to control individual room temps to a degree) So am I missing something? Or are the contractors just vastly over sizing (as seems to be the case with many in A2W?) The units themselves aren’t massively different in price as you go bigger, but the running costs almost certainly will, particularly if they end up significantly oversized. Any input is appreciated

Hi All As mentioned in couple of previous posts, we are renovating a house with Warm Air heating. We are happy with the system but it will not work after renovation (not possible to extend the system). Since we will update the whole system, one of the alternative is to use AC for heating and cooling. DHW can done by solar, E7. One of the issues we noticed was that EPC system is very limited. Our current Warm Air system has a new oil boiler with 90%+ Efficiency but EPC person couldn't find what to enter in system and entered lowest rating for heating. Few questions: Will we end up with similar issue if we use AC for whole house heating because it's not common in domestic market? Also since Air to air heating should use lower temperature than air->water->air so CoP should be better. Can anyone confirm this. Is anyone using AC for whole house heating, if yes what's your experience? Thanks

I'm about to start the first fix for plumbing and electrics for new build that is as close to Passiv Haus as I could get it and spent a lot of time trying to design out problems from solar gain - Brise Soleil features included in design etc.. Also spent a lot of time thinking about heating (ASHP) and wiring and tried to future proof things as much as possible so will run miles of cat6 cable just in case. But this latest spell of hot weather has made me realise that overheating could still be a problem and I've not really considered options for active cooling. A/C would be the best option and could be run for free from Solar PV. So, I'm wondering if it is possible to put in some 'standard' A/C pipework for the bedrooms just in case this becomes an issue. I was thinking of a standard split A/C system with a single external unit and 4 internal wall mounted units. Would I need to get a design done to size pipes correctly or are there standard sizes (ideally pre-insulated pipework) that I could put in as a first fix item ready to conect up later if overheating was a problem. Any advice, ideas or suggestions much appericiated.