SteamyTea

Seems the closet to Bristol one gets, the more of the ground floor gets covered. If I dig down more than a metre it would be called a tin mine.

Really don't know. There is nothing inherently wrong with using ply, as long as it is the correct sort. Sheets are usually marked up somewhere, so you should be able to find out what it is. https://www.trada.co.uk/publications/info-from-other-organisations/the-builders-guide-to-plywood/

Looks like shuttering ply.

Not my installation. I would just dust off my old RE Science books, the laws of thermodynamics have not changed.

You can pick your own hallucinogenic mushrooms for free. There may be some near a turbines base.

That is why buffer tanks must always be fitted.

I think your Mum is calling you to go outside and get some fresh air.

Really simple enough to make your own. Just some lists and basic functions. If I made you a spreadsheet, it may not show the information you want to display in the format you want.

If it is the correct grade, then yes.

Trouble with that is that there is not a huge knowledge base in the plumbing trade. Many installers are the same people that jumped on the PV installation a decade ago. The big difference between a thermal boiler and a HP is that efficiency is best when the HP is running below its maximum performance. This us why they are oversized. This us not the same as fitting a more powerful combi boiler. They are sized for DHW needs.

It is only recently I have heard any mention of waterbars. Have the regs changed?

Yes. The thing to remember is that you need to stop cold, outside air, blowing across/through the insulation. If air flows across/through insulation, it is the same as having a greater wall area to loose energy through.

That can hide a lot of sins, and holes. You need to make sure that the exterior, OSB I am assuming, is airtight. That is where the losses happen. And, as @ProDave said, at the top and bottom of the walls. Especially true if the roof is a cold one. Between floors, that space between a ceiling and floorboards, where it meets the walls is the tricky bit. I hope that not too much insulation has been fitted before you can check.

Then glue or tape everywhere outside air can get through. Then tape the insulation into place (why did you not go for celluloses, that insulates are fills holes up. Then when the vapour control layer is fitted, tape that up, including all penetrations, no matter how small i.e external light cable, telephone wire. Then make sure that nothing gets damages or pierced when finishing the rest. Plumbers don't care about airtightness, so watch them carefully.

Well that will look like it is doing something. It is general quality of work. Attention to detail everywhere, not what is just easy to see and do. If you are building a brick or block place, are you getting the walls parge coated? No good relying on plaster to stop the air leaks, it is in the wrong side of the insulation.

Then get a stick, beat into him that airtightness and properly fitted insulation are important. Then beat him again. And again. And again just in case. Tell him that if you don't get an airtightness number of below 0.5 ACH, then you will send him your electricity bill every month. Then beat him again.

Not that big, it is the 1m size that will limit the amount of insulation. Can you make it 1.5m?

Yes, this is why older houses tend to use a lot of energy. They leak air and the insulation levels are very low.

The actual physical size of the house is irrelevant, it is how much energy it uses and the peak power needed (that kWh and kW thing again). It is usual to oversize ASHPs as they produce a better CoP (the performance multiplier) that way. Think of it as a car, gently cruising along a deserted road the fuel economy is quite good, but accelerate up a hill and it drops significantly. In car terms it is know as the specific brake fuel consumption and often larger engine cars produce better fuel economy (it is to do with the cylinder area to power ratio).

Yes. That is down to decent insualtion. I added extra to mine as when I changed it I had to get a like for like replacement. Some people have gone down the Sunamp DHW storage system as the losses are very low, but they cost a lot more than a cylinder. If you are not totally committed in your house design yet, consider fitting the cylinder in a larger cupboard so that extra insulation can be added.

You got it.

No, I am on E7. So resistance heating. The grey columns shows my usage (two charts up), but if I had an ASHP, the heating time could easily be shifted by 10 hours.

Yes. That is the top of the tank temperature, the median temperature is lower, but I can take a shower with 35°C water quite happily.

I could do it, and have the qualifications to back it up. But it is not worth doing it. Not as if I could charge you £1500 consultancy fee. what you need to do is break down the system into each element, then see what is the most efficient and the least efficient, then aggregate the lot and compare prices. It is what spreadsheets were made for.

How hot do you think stored water needs to be? Here are my temperatures, and I don't run out.