JohnMo

Not sure it actually applies to ASHP either. Now had two and both performed the same on heat and cooling. My ASHP is currently chugging away cooling the floor at a CoP (EER) of 7.5, so doing well for a heat pump designed for heating. A2A will switch between either as long as it is not a cheap as chips cooling only one and includes defrost functionality.

Or maybe don't do ducted, do wall mounted and no cross talk

10W/m2 ties into passivhaus heating requirements, that can be done via MVHR if you want, but doing any cooling via MVHR is not really that successful. A2A could do both. Do DHW via direct immersion heating. Not really cost effective to do much else with A2A. Even with an ASHP I do direct anyway, not noticed any uplift in electric cost since I changed over. But for primary heat source, buy carefully, do your research as performance can vary hugely. As can the I'm fukced off with air always blowing at me factor. Maybe if doing A2A look at ducted systems.

Personal choice

Basically, same design really one uses water the other refrigerant

No not noisy, but there is some fan noise depending on fan speed.

Be careful if you bother doing a cooling heat gain calculation, as instantaneous solar gains can give you a huge heat gains. Others on here have tried it got 20kW cooling requirements and 2kW heating requirements. Then got bogged down with indecision. Size your heat source for heating needs, accept cooling isn't perfect, but better than nothing. Or go full A2A. Be pragmatic or pay £20k for a good plated solution. Think @Nickfromwales did a cooling solution where he cooled the upstairs/downstairs hallway instead of the bedrooms directly. That sort of solution cuts the number of fan coils needed, moves noise away from bedrooms and any drafts away caused by fan coils.

So assuming this is without all the plasterboard etc fitted. Going better than 0.64 is chasing numbers, to say look at me. Further gains aren't worth the cost. Get a couple of tubes of air tight mastic if needed.

Fan coil brands. Brand doesn't matter for ASHP. Good ones let you adjust the temp of water to enable the fan to start with a different temp for heat and cool. Poor ones are operated on a fixed water flow temp, which may not suit your setup. I have Myson iVector MkII fan coil, which is good. Panasonic, Daikin, Cool Energy all have good fan coils and many others. If you have time look on eBay many bargains come up or shop around as prices can vary hugely for the same thing. Some cheap fan coils are set up to just heat, so be careful read the install manual. Yes, one circuit feeding UFH and fan coils. But to this you need to size the fan coil to the expected flow temperature.

Why not spend a bit more and get one that does cooling and heating well. If the performance isn't quoted as good, maybe the indoor unit isn't that good either, noisy and drafty.

Depends on inside temp and humidity not outside. Easy way is set to a fixed flow temp. Generally keeping flow temp above 14-16 degs is fine. It depends on the first sentence, that depends on ventilation system etc

One thing stands out and it the price, if compare to an ASHP it has nearly all the same components, it will have an air to refrigerant condenser/evaporator, fan, compressor, a casing, a controller, only the thing is the refrigerant to water heat exchanger and pump are missing. But its 10x cheaper - and everyone says an ASHP has to be expensive because it's complex, this sort of proves the point it doesn't. It may not have have a defrost cycle built in but if it does heating and cooling it will have all the hardware, which is a 4 way valve.

I did mine almost the same as yours, but stopped doing block work at dpm level. Then backfilled floor to get a level site. This allowed the DPM to be installed and taken up the external walls. Above you can see where my internal wall block work stops DPM in place with rebar ready for concrete pour. Once you have poured your concrete, you build the internal walls up from the concrete directly above your foundations. This image show the top of the stub structural walls (after floor insulation and UFH added and prior to floor being poured) You have just carried away and built too high. You need detailed drawings and make sure your workers understand them. Suspect you need to remove the engineered bricks and Marmox blocks only, depending on where you have defined the DPM/DPC levels

To me if have fibre, you have fibre connection. It not a new site, it's just a new house, on an old site

Large bifacial PV panels? If wood, vertical slates not horizontal. Think stairs balustrade not fence. It also has to satisfy wind load requirements, impacts and not fall over. These requirements change with fall height. Look up balustrade requirements.

So are you planning electric UFH in the house? Sounds expensive to run.

If your anywhere near there on a new build, something is well wrong. UFH the parts are cheap enough. Your heat pump doesn't need to cost much either, mine was £2100 including VAT, you can claim the VAT back on new build. I would do a direct cylinder and just do cheap rate water heating, a cylinder is about £500. Then it's a matter of sourcing the fan coils. One in each bedroom. If you want to run fan coils at low temp for cooling you need condensation drains on fan coils and an electronic mixer, other option (the sensible one) run it at same temp. Your most expensive bit is the fan coils. If that's the fall back, why are you being anal about cooling - be pragmatic install A2W simply as above and actually have cooling. (Don't bother getting ripped off by a grant scheme)

If doing as above the normal thermostat doesn't comply as it has to be non self resetting, a dual function cylinder thermostat would comply or a stand alone non- self resetting one complies That is indeed one way to achieve compliance, but not the only way. From G3 Regs The selection of safety devices should take account of the physical location of the devices, and the design, confguration, location of components and performance characteristics of the system to which they are attached. 3.18 An acceptable approach might consist of: a. a non self-resetting energy cut-out to disconnect the supply of heat to the storage vessel in the event of the storage system over-heating; and b. a temperature relief valve or a combined temperature and pressure relief valve to safely discharge the water in the event of serious over-heating. Alternative approaches to this are acceptable provided that they provide an equivalent degree of safety. Unvented hot water storage systems – systems up to 500 litres capacity and 45kW power input 3.21 If an indirect supply of heat to an unvented hot water storage system incorporates a boiler, the energy cut-out may be on the boiler. Narrative from me. As a heat pump cannot achieve high enough temps to allow boiling of the water (even R290 can't get hot enough) a primary control is there by default. If the heat pump uses an inbuilt immersion that immersion has to have a non- self reset thermal cutoff to comply with regs For the regs a heat pump is a boiler. Diverter valves - To comply with G3 Building Regulations. When installing with an unvented cylinder, Port A must be used for the hot water connection to the cylinder heat exchanger and Port B for the central heating connection. This means the valve when de-powered shuts the flow to the cylinder.

Yes

If you are getting mould its really a ventilation issue that needs to be resolved. You will get two camps of answers here, but I didn't and would bother with UFH under shower or a bath

Why would you be doing an S plan with a heat pump? That isn't the way to do heat pump plumbing, maybe ok for a boiler, but still wouldn't go that route. You should be using a diverter valve, which is your positive energy cutout. Primary pipe from heat pump, to diverter valve, normally open route to CH and the normally closed to the cylinder. The diverter is controlled via ASHP controller on a demand for cylinder heating. ASHP ramps flow temp up for cylinder heating. Your ASHP is equipped with the safety features to only need that.

But that is real life. Your reinstatement is based on normal terms, not self builder, buying carefully, working long days efficiently etc. Realistic pricing is £2500/m² possibly more depending on spec.

Sounds pretty weak. If you want a stronger version but also insulated use Compacfoam. Make it deeper than 20mm by doing a double layer glued and screwed together.

Maybe not, A2A is ok for £2.5k only and almost no one is approved, so don't hold your breath on that one. If you assume UFH is just part of house build cost. It all doesn't have to cost a lot to build a good performance system. I never bothered with the grants, would rather pay myself than get ripped off. Simple direct UVC for DHW, cheap as chips, save around £1000 compared to pre plumbed heat pump one. Charge on time off use tariff. Would be surprised if you need more than a 4kW heat source, from size of house and assuming better than Building Regs. If you want Aircon performance add a mixing valve to system and run fan coils at 6 degs, or just oversize the fan coils, decent fan coils have the output data for different flow temps. Or do everything A2A, don't bother with UFH. Still do direct water heating. Spend the money saved on a good system with good airflow regulation. Having lived in hot countries a number of years, the airflow became a thing of hate, once the novelty wore off.

The F gas solution doesn't look cheap, may be wrong. Could be a good system, but I would go A2W and have fan coils (water to air) in bedrooms and normal wet UFH. A pragmatic design could be pretty simple. Design for heating, accept cooling may not be perfect but way better than not having cooling. UFH will make house feel way cooler than the air temperature is. The fan coils in bedrooms will leave rooms for a comfortable sleep. First job is looking at heat loss and sizing an outdoor unit. Then room by room heat loss. Design UFH (not some cut and paste job by UFH suppliers). Size fan coils to provide room heating at under 30 degs. Then run everything as a single zone. Fan coils will modulate fan speed to keep room temperature stable. The above assumes you are talking about a low energy house.