JohnMo

The glass sits in a robust aluminium channel, the channel is bolted to the wood. So glass and wood are completely isolated from each other.

Looks AI generated. Not sure what your full scope of work is, but speak to an architect first. They will get proper drawing done and engage a structural engineer as needed. If you think you need a structural engineer you most likely doing stuff you need planning for anyway.

Different bits need different strategies depending on what it is. DHW piping should be insulated, it adds unwanted heat in the summer to house. You may also suffer heat loss at cylinder, think the 2m around cylinder are supposed to insulated anyway. CH piping if you are running WC most parts of the house are going to be a similar temp including voids so any heat gains are fine. If you are running cooling you may need to insulate anyway. Cold water wants to stay cold so you may need to insulate depends on routing. I have the bore hole kit outside in an insulated shed, so stays pretty cool. Pipes in-house are mostly in concrete below my floor insulation, only bit not is encased in roof insulation on its way to hot water cylinder. If your cold pipes are in the void between floors your cold water is likely to be 20 to 21 degs most the time. Insulate to death.

You have basically taken a passive slab and killed all its benefits. You have no continuity of insulation. Take a look below, you can follow the insulation in the floor and up the walls. The slave takes the structural loads the block work sits outside the insulation. Your Marmox block works but is an expensive bodge.

Why not put heat pump at the out building and then pipe to house? unless the outbuilding is huge the 32mm pipes sound over kill. We have a similar out building and have piped in 15mm (around 10m each way). We have 210L and have never run short of water even when we have an additional 4 staying with us. We heat to 53 degs generally. Not sure I would want to heat an additional 100L every day just in case. PV diversion isn't worth it, export it first.

Why do you need a buffer in the plant room or at all? Have you considered bend radius to get the 32mm duo piping into the plant room? I would get the UFH manifold and cylinder next to each other and make the plumbing super simple. As said dump the buffer. Why not have the ASHP the other side of the external wall and take everything through the wall?

We had huge pumping lorry 4 times, so a lot of wash water and unused concrete. Basically got it dumped on our driveway, then broke up before it fully set where it was bit thick. All of it is under our drive way.

I've been able to make these work cost wise, especially when you use a time use tariff. Even with an ASHP I just do immersion heating.

Keep it simple, UFH which allows heat and cool, if you have an upstairs fan coils in bedrooms. It's cheap enough without any grants

To me it looks a complex solution to allow heating and cooling and is possibly daft money. Not really keen on a solution that is reliant on one manufacturer as one bit does most likely it all does. I would step back a little. Have a rethink. 1. An A2A solution (Aircon) do it for whole house and heat and cool. Do DHW via a direct UVC. 2. A2W (ASHP). Dump the idea of a buffer. If you want cooling think fan coil to replace radiators. You can keep your micro bore, but do a close couple tee instead of buffer. Way less chance of flow and return mixing. Then balance flow either side of CCT.

It's not an Aircon unit, but a A2Wso connects to wet heating system. Should do cooling as well, but depends what it's connected too. So may need more information

They are guidance - MI are what you have to follow if any different from the guidance. It's the same for all equipment you add to the house - manufacturers instructions trump building regs. Fire detection - it's there to save you and your families life, follow the manufacturers rules - so they work as expected. Cut a small slot in the plasterboard to get a wire where you need it. You will be plastering anyway, not seeing the issue. Could have fixed quicker than posting on here. Your electrician should know all the rules and ways to get cables from A to B as needed.

Your name always throws me, Scottish BR do allow sealed battery powered. English mains only

Couldn't think of the chemical name. Gorilla glue isn't the same. Tiny tube that likes to stick your fingers together.

Super glue

What do the manufacturers install instructions say? You can always install 10 year battery version of the detector, then you need no services

Doesn't really matter what you or anyone else likes, your wife wins - sorry it's just life, or live with the throwback for the rest of your life living there. But I agree with the wife choice

That makes zero difference, you do not need to trade anything in. You are applicable to the scheme. But that said, so was I, but did it all my self without a grant, not really that expensive. UFH is the way to go with a well insulated floor. Then run it low and slow whatever the heat source. After having gas now heat pump, the cost saving with heat pump are ace. Battery makes all the difference (with or with out solar) only pay 10p per kWh and get 3 charge periods a day if I need it.

What is that? All heat pums are suitable! Not all cylinders are suitable for heat pump heating. We just heat our cylinder now via immersion, we are on Octopus cosy tariff and it allows heating 3x a day on cheap rate. So although there are advantages using the heat pump we have just stopped bothering and immersion adds very little in real terms to our bills.

If your digging the floors out, are you doing UFH? Would be a simple and pretty cheap way to add heating downstairs. If so, the more insulation the better. Not a fan of your hot water solution. Electric showers are just rubbish after having a unvented cylinder. Make room for a small/medium cylinder heating via immersion. Add a decent shower mixer. Your going to be running cold pipes anyway an additional pipe is easy while your at it any way.

What is the assumed U value for your windows and doors? Lots of glazing is different things to different people and can make a huge difference to the heat loss. I would go through the SAP report line for line to see what assumptions have been made, sounds shite in shite out to me somewhere. Post your report

All seems fine, been doing cooling at 14.5 degs since mid May as well, going by the flow meters on the UFH manifold which are nice and clear.

Sort of. Treatment plant and soakaway are around 400m apart, and although it should gravity feed SEPA insisted on a pumped solution. So we feed from treatment plant to another tank with a pump at the bottom.

Couldn't agree more. Doesn't matter industry you are in. Definitely not a necessary unless one side or the other is an arse or full of their own self importance (maybe the same thing). Had one designer that wouldn't entertain any input from me (not really the designer but his boss), so the company got sacked on the spot very early in the design process. Design is a two way process, it may look pretty if it can't be built easily it's a rubbish design by a poor designer. But back to the slab, your structural design should detail rebar and concrete specification fully. If it doesn't it should. Scottish system makes this all blissfully easy, structural design not completed - no building warrant - no permission to build. Curing agent or not depends on few things, such as outside temperature, so in winter in Scotland is completely different from summer in England. Get advise from your structural engineer, as they should be giving you the structural design certificate.

On a new build - I doubt it. Our max flow temp is only 28 at -9. So well below body temp, actual floor temp a few degs above room temperature so even cooler. Even without the previous how long will you be spending walking on the steps. If well insulated they will be close to room temperature?