PeterW

That isn’t possible unless you go to Aerogel. Kooltherm is slightly better than the standard PIR but you won’t get the insulation value halved.

This is a high pressure unvented cylinder. You have mains pressure water. Yes I think so.

How big is the hot water cylinder and where is it in the house ..? Could change for an unvented cylinder and get mains pressure hot water and lose the attic tanks in the process. Would give you better options on the showers, alternative is fit a pumped shower but that may need changes to pipework.

That sort of workmanship would get you thrown off most housebuilders sites ........ ... it’s far too neat and they don’t like that sort of thing ..!! ?

So that silver thing on the right looks like a Schraeder valve. Undo the cap and push the pin and see if you get any air out.

@pocster do me a favour and take a close up of that brass thing on the top rail please. want to see where the thread is and if it has a hex top.

https://www.bes.co.uk/aladdin-autovent-hv30c-1-ufh-23156/?ref=gs&gclid=CjwKCAiAjeSABhAPEiwAqfxURbtWoAU0g8qU196pTw48ZS1fE9ePaN0lSOW2FIRoelS47sVh1uZXWxoCCHgQAvD_BwE one of these ...

The canisters are, the valves are not as gas tight on the guns themselves and due to the volatility of the liquid and the gas, it will leach past the valve head if the pin is not perfectly clean.

Ok to get rid of the air permanently, isolate the manifold and open the top drain valve. Then remove the brass bleed valve head and replace it with one of the Aladdin automated UFH bleed valves. Then repressurise the system, bleed the top rail using the pin and it will self bleed the remaining air over a few hours running.

Oh and another vote for the Lossnay units. They are very good and have an enthalpy heat exchanger as standard - hence why they cannot be used in permanently wet environments. What is interesting is in winter the external intake RH is consistently higher than the extract, even from bathrooms, as it is blended with extract air from all “wet” sources which are unlikely to all be creating steam or moisture at the same time.

@Adsibob out of interest how airtight are you making this renovation / extension..?? MVHR retrofit into older properties is variable in its success as it needs a decent level of airtightness.

Class B are available in red or blue, commonly called Staffordshire blues. They are used below DPC for a number of reasons including being near impervious to water and very strong under frost damage situations. Category 30/50 are ordinary bricks with higher strength - I doubt they meet the frost damage level of a Class B. You will only see 2 courses at most so I would just get the closest Class B to your scheme in red. Just check manufacturers as they do look slightly different colours between factory locations.

Search for a quote by @canalsiderenovation on the forum as the costs for the panels are on that but it’s about £30-40 for the trays.

Really ..?? Count all your double battens etc for the slates, and take a broad brush of £75/m for material and labour for a slate roof. Then look at the cost of the systems and you’re probably looking at around £40/m to purchase and I would expect around £15/m to install. That’s a £20/m saving, and you have a system ready to receive the panels. For a standard 14 panel install, and panels at ~£100 each, your saving pays for 5 panels so you’re at net benefit with using the system with PV (if required for SAP).

Ok my point was you need to check - NuHeat have changed their designs over the years so it’s not as simple as saying “they fit” as they have changed voltages and mechanisms over the years. Easiest way to check is take off the actuator and then trigger the stat and see what the actuator does.

If you’re lucky that your council has tree officer then you may get through ok. If like around me, they have been replaced with “Environmental Support Officers” then please be ready for a long and drawn out argument and battle of the qualifications ....

@Andy brown I would go with a gas boiler without a doubt in that situation. If you’re having any underfloor heating don’t forget the buffer tank.

@Mulberry View I’ve had another look based on your comments. I think the office (10) doesn’t lend itself to being there as the view from the front door is a wall. Why not move the office to top right and use the space under the stairs and then move the utility door direct in line with the front door ..? It would give a view through the house and you can also lose some of the space in the plant / utility as currently the plant room is 50% door and corridor. May have a hack about to show what I mean..!

Any system needs a buffer tbh as it stops short cycling of the heat source when only one loop is calling for heat. With thin screed I would go with spiral as you will get uneven heating otherwise. You also won’t get a boiler to condense at those temperatures and I would put the buffer in as above. Just let the buffer call the boiler, a pair of stats can be used in tandem to stop it calling until the buffer is quite cool and it will manage the system better. No boiler will cope with only one of those loops being open and calling for heat.

Do you really mean you have a 15mm supply pipe or a 15mm meter orifice ..?? Your supply is probably 25mm MDPE from the main - that’s the first thing to check. Upgrading internally once that is confirmed is your best bet, use 22mm Hep2O and look at ensuring you have a decent flow rate too.

I see lots of wasted space and a bedroom upstairs with no access to a shower unless they go downstairs ..?? Room 2 has to go to Room 8 for a shower ..? No master bathroom or bath other than main en-suite ..??

Finished Floor Level

Yes - sharp thin blade will take it off as will a guitar string as a cutter.

can you clarify those numbers ..?? That would indicate at 8°C your heat pump has a CoP of 12..??! And at -3°C it has a CoP of 3.6-4.5. I’ve never seen a unit that can do that - a CoP of 4.5 at AW 7/35 is pretty much the benchmark number, not at -3°C What is the building constructed of, and what’s the heating ..? UFH..? How long does it run for ..?

@nodI had always been told 3:1 sand cement base then 4:1:1/2 sand cement lime for the top coat. Is that correct ..?