JohnMo

Not really always correct - Frametherm 32 has an R value of 0.032 and PIR 0.022W/mK so 50% difference not 100%. There is no shrinking with mineral wool, and you are not bridging with a lower R value expanding foam.

Just use a heat pump cylinder 400L you easy get a 4-5m² coil in. Even a 3m² would give quick recovery. And possibly stay in condensing mode for most the reheat if you set it up well. But if you have room for 400L cylinder 2x 210L slimline heat pump cylinders would give way more flexibility and faster reheats and you would get 6m² coil out the box.

I would just do mineral wool something Rockwool Flexi or Frametherm 32. Then under-draw in 60-70mm PIR. Easier life, as good U value on paper and likely quite a bit better in real life. Better decrimant delay.

Slates. A copper strip on the ridge..

Sort of Use the heat-loss formula: Q=U×A×ΔT where U = floor U-value (W/m²·K) to the underside/cavity, A = floor area (m²), ΔT = temperature difference between the warm floor (mean UFH floor temperature) and the space below/crawlspace/ground (K). So you need to use your average UFH flow and return temperature. Average winter temp is around 7 degs (void space temp), air is a good insulator if in a closed box, but your void will be ventilated, so not good. Best case U value will be building regs, it can be worse and compensated in other areas. But we will use 0.25. Flow temp likely to be mid 30s so 35 flow and 30 return so 32.5 mean. 0.25x100x(32.5-7), so 640W. 640 x 24 x 220, so about 3400kWh At 8p that's £270. If your flow temp is higher your losses get higher. If you can flow lower well done but I doubt it. The above is based on average temp, so milder days less losses, design day losses double. So on a -3 day your downward losses alone will cost £2.30.

this a cut and paste out of English permitted development rights Development not permitted B.1 Development is not permitted by Class B if— (a)in the case of the installation of stand-alone solar, the development would result in the presence within the curtilage of more than 1 stand-alone solar; (b)any part of the stand-alone solar— (i)would exceed 4 metres in height [F7or, in the case of stand-alone solar on land in a conservation area which would be installed so that it is nearer to any highway which bounds the curtilage than the part of the dwellinghouse or block of flats which is nearest to that highway, 2 metres in height]; (ii)would, in the case of land F8... which is a World Heritage Site, be installed so that it is nearer to any highway which bounds the curtilage than the part of the dwellinghouse or block of flats which is nearest to that highway; (iii)would be installed within 5 metres of the boundary of the curtilage; (iv)would be installed within the curtilage of a listed building; or (v)would be installed on a site designated as a scheduled monument; or (c)the surface area of the solar panels forming part of the stand-alone solar would exceed 9 square metres or any dimension of its array (including any housing) would exceed 3 metres.

Does a pergola need planning - no generally. Think most of what is posted is for a building. When does a pergola become a building - when you enclose roof and sides. So now the question is does it become a building if you only cover the roof and leave all sides open? That is the question 1 Question 2 is, can I install solar panels at the front of my house that are not on my roof, but on a garden structure. Generally no, without prior planning permission. So can you install a solar pergola at the front of your house without planning - no.

Generally you need mains power, supply and return piping, a controller in the house (your sounds like it's wireless which maybe good), cylinder temp probe back to wiring centre, 3 way diverter valve power. But you really need to download your models install manual to get the correct details.

G99 and G100 compliance listing https://connect-direct.energynetworks.org/device-databases/generation-device/SUNSY%2F04876%2FV3%2FA2 Bimble solar seem to have links to all the certs on the product listings

I would look to keep this all simple. Something like a Sunsynk hybrid inverter, set export to zero. The inverter will allow to charge battery from grid and or PV. Inverter will feed house when there is battery capacity and or PV, otherwise draw from grid. This way you give nothing to the grid, but can charge from grid when no PV. Use a time of use tariff get all your electric on cheap rate or from PV.

LoopCad on a limited time free trial. Save everything to PDF and print before time expires.

The heat pump monitors cylinder temperature and schedule at a call for heat the heat pump powers the diverter. Would assume the wiring centre is within the ASHP casing. Why limit yourself to one make?

Hitachi and Hisense both have the same outputs. It's the 4.4kW model. Been doing some digging and Hitachi has or had a joint venture with Hisense for HVAC (including ASHP), so some common parts maybe compressor as outputs are pretty similar. They also both use dip switches for various settings. Hitachi needs an additional on kit for cooling and Hisense doesn't. The Hisense is £2000 including VAT. The heat pump also has the expansion vessel etc in the casing.

A heating system with DHW cylinder will have two expansion vessels, one for heating water (goes CH and for heating DHW) the other is for the contents of the cylinder. The integrated one will cover the heating water only. But only to a given CH water volume. High volume systems may require additional expansion. WiFi should just be access to a portal, shouldn't be required to make system work.

Sorry just seen this, yes pretty basic boiler. Maybe better spending your money on a better boiler. Can you estimate it's thickness? Your B&B plus screed say 250 to 300mm. If it's suitably insulated it will be closer to 450 to 500mm thick.

Thanks

For me you are wasting a load of money and effort doing UFH. Block and beam and thin insulation you will be chucking money down the toilet year on year in increased running costs. I read an article the day about radiators and cold feet. The reason people get cold feet - the heating runs an on off strategy with high temperature radiators. Radiators don't really radiate heat they heat air via convection. The convection current is quite strong with high temperatures. The hot air goes the ceiling and cold drops to your feet. Thermostat stops the radiator the room cools, you still have cold feet the cycling repeats. Solution is low temperature heating, so with radiators you can run weather compensation or load compensation. So the heating is lower temperature and more continuous. Your easiest option is to get your boiler to run opentherm and move to priority domestic water, so you can get two flow temps one for DHW heating and a variable temp for heating. You need to share your boiler details also.

You need to ask yourself do you need PV, what are you going to use it for. Then does your proposal make any sense? Are you doing battery?

Strictly to question - no it not touching the grid, so has no influence on grid via export

All this stuff is down to personal preference, risk profile etc, no right or wrong answer Two sorts of glycol, the stuff you put in the car - highly poisonous. The stuff you put in heating systems not poisonous. Yep

Agreed, if they don't tell me in black and white data, I take them off the list of possibles. Hitachi, Mitsubishi and Hisense seem to give you all the information. Other are either a stupid price or tell you nothing. It also has to do cooling out the box, so no add ons. Lowest output at 7 degs so far is 1.68kW. Somewhat better than my current 4.5kW.

Been reluctant to take it apart, as no issues since then. Done numerous DHW heats etc, no issues at all. So will blame the high winds and grid related stuff for now. If it occurs again will get the tools out. But did research a better replacement that modulates way better than mine does.

Bifacial panels provide that. My 2 panels including inverter mounts and cable etc was £410 for 1kW all in. If I had installed 2kW would have been about £600.

The heater in the crankcase is there to keep oil temperature higher than refrigerant dew point, to stop oil dilution. That is it's sole purpose

This what my manual says about startup and the same would apply after a prolonged power outage. "The unit must be connected to the electric mains and placed in STANDBY (powered on) by closing the master switch at least 12 hours before start-up. This will allow the heaters to adequately warm up the compressor crankcase (the heaters are powered automatically when the switch is closed). The heaters are working properly if after a few minutes the temperature of the compressor crankcase is 10-15°C higher than ambient temperature." So glycol or antifreeze valves after a long power cut you have no heating for 12 hrs. I chose a generator to get around this issue, then added a battery that covers the whole house. So even if I put the ASHP on standby to conserve battery, ASHP is ready to fire up as soon as mains comes back again.