JohnMo

I did mine from a kit, it's 70mm thick wood, easy and quick to build. Then built a standalone from inside for additional insulation, same with floor and roof. Things to consider Lightweight building equal really hot when sun comes out. But quicker to heat up in winter, but cools soon after switching the heat off. Heavyweight more stable temperature but takes longer to heat up in winter, but slowly cools. Timber frame and dense insulation. Yes, PIR no. Block work, mineral wool batts in deep cavity yes, PIR no. SIP no

The expensive one looks ok and more controllable than the cheaper one. Really depends on what you want.

Not really, we use huge long hose pipes (200m) so happy with every drop of pressure.

On an UVC the thermocline rises up the cylinder as hot water is consumed. The hot water coming out when nearly depleted is still usable as hot water. On a thermal store the thermocline will operate in the same way, climbing up the cylinder, but leaving more and more of the coil in warm to cold water. So not getting the heat transfer. A plate pack helps as you get more useable hot water. The other issue can be, you may have to heat the thermal store via coil or plate exchanger also, as with a lot of boilers, nearly all heat pump needs a closed pressurised system to work with. This just makes less usable stored heat as now you operate via two heat exchangers.

Yes

That's a big pipe, are sure you need that big? Our water comes into the house through a duct under the foundations. Up to the stop cock, prior to any pressure reduction the pipe takes a turn left and down to its own isolation and the down through the same duct and then up to the outside tap. Stop cock stops all water flow, and outside tap has its own isolation also.

Did all the calcs and just couldn't justify Marmox as they adding nothing in real terms from the design I posted. The Thermolite blocks are in a dry space so thermally stable and twice the height of marmox. Ours came out at 0.09 U value. As I said our was a standard ground work contractors, doing most of it, but I did all the insulation and UFH, they can back concreted over the top. I then built the walls.

Similar build to ours, but we are 195m2 and 3 bed, 210L cylinder and a 6kW ASHP, although max heating load is 3kW. I would be your own heat loss calculations. May have seen big house made up the numbers, you can afford it quote.

We couldn't find anyone up here so decided to do a modified version of some more traditional. We are on a sand hill so lots of belts and braces added. But a simplified version of this is doable with local labour for not much cost wise. Pretty much thermal bridge free. Not shown is a 70mm upstand I added to screed edge. Used 200mm of PIR insulation under a fibre reinforced concrete screed 100mm thick.

Depends on circumstances and house layout, plus size of windows. We have one wall of glass 6m tall and 7m wide. Biggest heat loss of the whole house is that wall. Halving the heat loss was money well spent (1.4 compared to 0.7 U valve), plus at -7 I can quite happily sit right next to glass without discomfort.

I read all that when designing our house. Then looked at calculations for inside surface temperature - triple glazed was something like 1 to 2 degrees below room temperature, while double was nearer 10. Passivhaus specify triple glazed not just because of heat loss, (in fact they are not really required for heat loss at all) but are required for the comfort criteria.

An approved detail TN 10321 - Condensate drainage and unvented hot water systems FD.pdf

This is as simple as it gets for just DHW, select the right combo of labels and immersion and a DC isolation switch switch between the two. Semi clear day today nearly 7kW installed PV and at 11am I am generating between 2 and 4kW. So about half installed capacity. So you need to rethink number of panels and how you hook up. Either water on its own in DC or AC connected and leave to cover house loads. Any less than about 3kW is a waste of time really. 3kW on a good summer day will also heat your water and cover all house loads.

Define exactly what you mean by insulated raft, many meaning used by different people.

Internal drain is fine

Sounds like a bargain, not, but 400L cylinder is a big cylinder, use less zones that are bigger, then get a smaller or no buffer. Would be cheaper to DIY without grant, unless the whole house is being replumped. Big heat pump, either huge insulated house, or just too big.

The alternative has always existed Vented or thermal store, such as a Harlequin - no discharge piping, no G3. Fit for purpose, vented is what most old houses have anyway. Same as an immersion in cylinder just moved so it doesn't sound as bad - same effect on UVC if it goes wrong. You keep trying to reinvent a wheel which is never going to happen. If don't want G3, use a different technology that doesn't need it.

Watch a couple videos, my first attempt was awful, now knife strip back outer sheath about 100 to 150mm. Adjustable pipe cutter use that to nick the wire layer. Peel back wires they all fall off at the nick really clean. Inner sheath cut with knife. Make up gland. Get all the dimensions from gland instructions - 5 mins tops now.

It's basically a cylinder full of heating water, not drinking water, it uses a coil or plate heat exchanger to make hot water for the taps. An unvented cylinder is the other way about. A cylinder full of drinking quality water heated by a coil or heat exchanger. An unvented cylinder is serviced annually because it's a pressure vessel, the thermal store is open vented so does not have the same legal requirement. However for the same size of cylinder an unvented cylinder delivers way more usable water. I had a thermal store and changed to unvented, it's way better. Regardless of heat source, gas or heat pump always install a heat pump cylinder with a 3m2 coil. For gas you can run in condensing mode and have quick recovery times. Once you are well insulated you create problems for heating control if you try to over think it, you need to keep things simple and the heating system open. UFH works well, with a thick screed, it becomes a storage heater, ideal for cheap electric tariffs and ASHP or blasting heat in once (35 deg flow for about 3 to 8 hrs) a day from gas. At it's simplest you need a good gas boiler (Atag, Intergas, Viessmann) or heat pump, a cylinder and 3 port diverter valve, UFH manifold (no pump mixer or actuator). The manufacturer controller or a single thermostat. Run a boiler on Priority hot water or W or X plan (nothing else). This will give two output temperature from the boiler one for heating the other for hot water. Cheap boilers don't do this. ASHP do this by default. We went from gas to ASHP mostly to get cooling.

Title says very simple? Why do you need a battery, it brings nothing to the party. Your grid connected the grid will smooth stuff out. That inverter is actually AC coupled so would be no use connected to a battery.

At those price I would tell the grid to take a walk and do a full off grid. Do you have plenty of space for PV? And a generator for mid winter.g

Why would you use a window buck in an icf, unless you live in the states. Most the drawings in the paper give quite a thermal bridge.

It 1st May not April, but a bit bonkers all the same, they will fly the nest anyway - or they ought to, so they grow up.

Inverters, just watch max amps and voltage as big panels will exclude a lot of normal inverters maybe not hybrid inverters choices. 5.5 to 6kW will be fine, most the time will be well below that anyway. B. No, you can always AC coupled, which is what I did, a little efficiency loss but that's ok. Most hybrid inverters will only do one circuit in black out so check before purchase. My AC coupled runs the whole house up to 6kW continuous load. C. Our GivEnergy all in one is settable to any export limit you want.

Armoured cable around the house? Ours is at back, so is consumer unit, but have a water shed (borehole pump etc) so have a second consumer unit in there via a big cable. So heat pump is driven from there. Only a single 3 core cable going into the house to drive a 3 port diverter valve on call for DHW.