SteamyTea

Fair enough, saves me bothering to explain why it can help isolate the problem. As you already know all the answers, can I have tomorrow's winning Lotto numbers.

Are they insured and what does it cover. Make sure you see the certificates.

Still raining, but listening to Woman's Hour. The language they use makes me blush. They were talking about making new rooms in houses for 140 quid.

It is Not what you typed Just being a pedant as I am bored waiting for the rain to stop.

Nor scientific notation. kWh. Or is it a Mac thing.

Dgtvnjjnb gbbbn There are 10 types of people that understand binary. Sexagesimal is more fun.

You need to stick the thermometer/RH meter outside, take some readings and see if it really is the air that is causing the problem. But is your building still trying out in places after years of inadequate heating and ventilation. Keeping the heating permanently on, while ventilating would speed this process up. Just saying.

Not how properly mixed concrete sets. https://www.understanding-cement.com/hydration.html

It is because you can change the shape of a 'volume' without changing the mass, this happens in corners. The shape is important as that affects surface area, and part of the unit of thermal inertial is m2. J.m-2.K-1.s-0.5 it is basically a case of working backwards from volume to mass to establish the lower and upper bounds for the calculations. The other reason is that the majority of the mass contributes little to energy storage, whether positive or negative. If it did, insulation would not work as well as it does.

I can't give personal recommendations other than my cheap Screwfix pump and combined mixer. But I think you need to think about the 3 separate sides of the design. The ASHP The water storage The Mixing system. As you already have the ASHP, you cannot do anything with that. So it is down to storage and mixing. There are basically two types of storage. One where you use the heated water directly (which I suspect is what you already have) and the other where the cold, incoming mains water is heated via a heat exchanger. This heat exchanger may be as simple as a coil in a cylinder that takes cold water in one end, and comes out the other hot, taking the heat from the stored energy in the cylinder. It may be a plate heat exchanger that sits outside the cylinder and has the hot water inside the cylinder pumped though one side of it, while the cold water is forced, via mains pressure, though the other side of it (I doubt you have one of these). The mixing is really just a tap with a valve that can vary the flow rated between the hot and the cold to get the temperature you desire. Some do this automatically, and some, like mine, manually (why it was cheap, but reliable). The main thing to know about mixing hot and cold is that the pressure must be the same on both sides, this is to stop the higher pressure forcing itself up the low pressure side i.e. into the loft storage tank, which would then overflow, and possibly collapse if the water is very hot (not likely with a properly set up heat pump). I like gravity fed, pumped systems as they are very simple to understand, reliable, cheap components and can be self installed, but they are noisy.

Bugger Somewhere on here is a product that can be applied in the wet. Might be what @Onoff uses.

This says it can do it. https://www.resincoat.co.uk/en/roof-paints-coatings/544-resincoat-liquid-rubber-waterproof-coating.html

Welcome. It will be good to have someone that has experience in ICF. A few people on here have used it, but they tend to be one offs, so the next person that uses it seems to me, to be just reinventing the wheel.

My guestimate was pretty close. Insulation, generally, needs to be within the airtight envelope or the cold external air just penetrates and invalidates it. This is why internal insulation is often so effective, but it is the detail between floors, extending cabling/pipework and the reduced living area, that causes problems. But it will probably make the biggest difference. Just sorting mine out almost halved my energy usage, and all I really did was improved the sealing of my existing windows and doors (finally sorted the front door after 16 years, almost). If you can get airtighness sorted, then you can fit MVHR, and get an extra bonus on reduced usage.

My nearest Metoffice station is reasonably close, but as it is so cheap to add an external temp/RH/air pressure sensor, it would seem silly not to. I like the idea of using others data, especially if it is prediction of the next days weather, but I am sure that can be worked out well enough locally (my cheap weather station calculates the sky conditions from just temp, RH and pressure, and is amazingly accurate. I wish I knew the algorithm then used, but never managed to find it. Knowing the weather for the next day would be useful as I am on E7, and down here the temperature can change rapidly in a few hours.

What happens when you loose connectivity?

Do you know your winter heat loads/gas usage. This is the important one for sizing any heat pump. If your annual usage is 41636 kWh, and assuming that you use 4000 kWh for hot water, that leaves ~37,600 kWh for heating. Now the coldest 4 months will use 2/3rd of that, so ~25,000 kWh, which is about a 9 kW heat load. It is usual to oversize a heat pump, though less so for a GSHP. So that 12 kW Nibe ones seems, on the face of it, about the right size. But £44,000, think about that, it is about half the price of my house. Or a very nice Tesla Model 3, which will save you more if you do decent mileage. This only leaves you two choices: Improve the building Gas If you want to improve the building, look at airtightness first.

Yes, and epsilongreedy, then see if we can get this topic up to 1000 pages. And you will still have a constipated pot.

https://improvementcosts.com/costs/roofing/home-roofing-cost/ Are you using Phillips Moss as your builder.

They never do for you, but that is because numbers are for the feeble minded and are just made up. You have to pick the right system components, not the most expensive tile replacement types.

I would still try very hot water and a stick. Or isopropanol, or even meths.

If it is PVA glue, just keep dunking it in hot water, and poke something down the hole.

I think that is a challenge to get the creative BuildHubbers to come up with a simple design that can be made by just about anyone, with basic tools.

Air is a fluid. Don't anyone, ever mention that MVHR can be noisy at night. And it uses electricity, 24/7. [getting my tin hat on, then me coat]