JohnMo

Because the material in the sunamp requires a minimum in flow temperature. Basically you have a change phase from solid to liquid and the keep heating. So if the melt temp is 55, all the energy has to be added at 55 or above. Anything below that does not add energy. A water cylinder adds useful heat in a different way as they do not rely on a phase change in the storage material.

Last week there was a thread and @ProDave and I listed our current and past humidity levels. Dave is North or West of Inverness in the Highlands and I am East of Inverness possibly 70 miles between us but different climates (we are not so extreme cold and if it is cold it's a shorter period). Enthalpy is good for long cold spells and keeps the humidity to sensible levels. We had a week at or around -9 and the humidity stayed sensibly, but we didn't bother with a MVHR pre heater, so the MVHR is possibly in self protection mode (although no lights came to say that). I would say if your not in a cold spot in the Highlands of Scotland, or need a higher humidity level for health reasons, the benefits of enthalpy heat exchanger are low, and also you possibly don't need a pre heater at all in the UK at all.

Not sure what you are trying to get towards with all the data. But currently outside it's 8 degs and 74% humidity. House inside (MVHR) it's 19 degs and 48.5%. No heating on. The summer house also has the heating off its 11.6 degs and 54% humidity (dMEV).

Didn't notice, so must be. Also looked at our summer house with dMEV and that dropped to 32.5% humidity on the same day, the weather at that time had been a steady 3 days of sub zero temperature. From the sleep foundation According to the Environmental Protection Agency, the best indoor relative humidity falls between 30% and 50%, and it should never exceed 60%. Other studies suggest 40% to 60% is a better range. So at all times stayed within the recommended levels, most the time it's at 40 to 45 range, mid May we got up to about 55 to 58% but was hot and had cooling on and most likely the windows and door open after. So no concerns, always in the recommended range.

You do need a ventilation strategy however. It's great getting rid of drafts, but you do need to allow in and out in a controlled manner, for a healthy environment.

Our last house was in a conservation area, the previous owner had double glazing installed under a grant by the council and they were uPVC. Would not be my choice. The ground floor still had the original (200 year old) wooden windows which we had refurbished. Had never heard of this until I came on here, have only bought and sold 10 houses, and the subject has never come up. The rest as @ETC says

@RobLe stated one reason for h environmental plus a safety issue, flammability. Reasonable write here. Note we are a moderate climate not a cold one https://sprsunheatpump.com/Differences-between-R290-and-R32-Heat-Pumps-id46798837.html

Was looking through some old drawings for our house and one iterations was timber frame 1.1 U value, build was Change the osb for cement board. And build fire resistance outwards.

So what you need to provide is ASHP make and model, then someone will know the answer.

Get used to it, it called a planning system, you will get asked for worse. COVID made things worse as it gave them an excuse to communicate even less.

From the photos not hot dip galvanised Have read https://www.galvanizers.co.in/blog/difference-between-galvanized-vs-hot-dip-galvanized-metal/

I would Supply to lounge, extract kitchen, use dining as a pass through area, the rest something like explained on the attached, almost no duct required. 615103-a-leaflet_multi_air_supply-en-dig-lr_5057512563596.pdf

I have winter data for MVHR, but wouldn't you need to overlay on my external temp, external humidity, internal temp and ventilation rates? On cold day I had internal humidity was as low as 36.5%, 14 days previously it was 45% and a couple of days later back to low 40s. House temp was pretty stable around 21 degs.

Almost the same, best way to compare is SCoP not CoP, SCoP comparison looks at efficiency over the year, not a small moment in time. Both examples below are the same output size ASHP. Vaillant (R290) at 35 deg flow 4.48 SCoP Maxa (R32) at 35 deg flow 4.48 SCoP 4.46 As said above system design is way more important, best heat pump in a poor system, becomes a poor performance heat pump.

I tried to do this with our house, decided it wasn't worth the effort/risks so just got frames. The wooden frame takes away 30mm from the sight line, you don't notice it. Ours sit in front of a steel frame. Cold bridge Your area at the bottom of the window is a big cold bridge. You need to look at a continuous insulation line. So at the bottom I would add a layer of Compacfoam and bring in the meet the floor upstand (would make this at least 50mm thick). This will have enough strength to take the loads and remove the cold bridge. Position in the wall depth will depend on how your walls are insulated the window needs to straddle the insulation. The concrete/block section needs a good look at as from a thermal design perspective is rubbish and will leak heat like a seize. And likely lead to mould.

You need to step back slightly and ask the question do I need it at all. If you use a good proportion of the water each day and don't have infirmed elderly people in the house there is a good chance you don't. This is a good write up on the subject https://www.heatgeek.com/hot-water-temperature-scalding-and-legionella/ Other than that tell the installer to get his arse back to change the timings. Or talk you through it. Every heat pump will have a different way to change the timings.

Good chance they are not actually galvanised, it could be just zinc electroplating (which us cheap rubbish and too thin). If it was galvanised you actually need an etching primer or an epoxy based Paint, to get the paint to stick on. But I would use Rust-Oleum® Stops Rust® Cold Galvanizing Compound Spray. Its 93% pure zinc coating applies a galvanized film with cathodic protection, which resists rusts, scratches and chips. It can go straight on zinc coating etc. Apply 3 to 4 heavy coats. Nothing else needed. Your stainless steel ones will rust if they used tools that were also used on carbon steel or have carbon steel grinding splatter on them or they used the wrong filler wire on the welds. Spray them in the cold galvanise spray also.

If they were galvanised (hot dip) after welding they should be good for about 50 years. That why they are galvanised.

That's still 10mm per metre. Plus the glass needs room to move. The examples for oak, the glass is secured by compression of EPDM and leaves everything some wiggle room, gives a water tight assembly and is easy to replace in 10 years time if the glazing unit looses it's argon and starts to fog up etc. Would expect your assembly fixed and bonded would lead to a crack glazing unit.

Take a look here https://sessile-oak.co.uk/oakFrames/glazing

No it's 83.3mm per metre. So if you need 150mm that's just under 2m at 1:12, or longer for a less steep fall.

If you boiler is serviceable use it. It will turn down to about 12kW. Which is quite high, but if you are in a leaky (heat) house that maybe ok. All boilers benefit from a long run time and you really need to minimise zoning (remove as many thermostats as you can) to keep system open, otherwise you will get short cycling. Short cycling basically consumes loads of gas for very little heat output and shorten the boiler life. Assume you will mix UFH with radiators? If so use an Ivor mixer for the UFH or electronic (expensive). Most other mixers are rubbish. You may benefit from adding weather compensation to the existing boiler, then run the whole system on WC, use the existing trv's as limit stops (set a couple of degrees above target temp) and the UFH on continuous on a set low flow temperature.

Do a search on Google for frameless glass and oak frame, there are plenty of example of what to. Not sure what you are proposing would work due to the amount the wood moves.

I just knocked posts in to ground, ran three lengths of wire top, middle and bottom and infilled with orange dayglow mesh cable tied to the wires.

Concentrate on system design, refrigerant makes little or no difference to system performance. Big coil cylinder (3m2+), design for no buffer and single zone. Unit sized as close to heating demand as possible. If it can't do cooling out the box not interested, that would include lots of Daikin units, Vaillant etc If I was buying new again as small a Panasonic R32 unit as I could get away with. Why, combination of decent price, spec and user friendly instructions. I would avoid any heat pump, that makes me have an indoor unit, or ties me into the manufacturer cylinder, that includes all Bosch units, split units (of any kinds).