SteamyTea

Trouble with that is that you may overheat the slab unnecessarily just to get an extra couple of degrees air temperature. If you take a 4m by 6m room, with the UFH pipes 100mm down, sitting on top of 100mm of another concrete, that slab will take ~5.5 kWh just to raise the floor up by 2°C. That is just to get an extra 0.042 kWh into the air. (Divide by the system power to get the time needed to heat up)

Plate heat exchanger to separate the circuits. But you are highly unlikely to have the heating off when the weather is so cold that the heating circuit could free. Or do you mean the ASHP frosting up when it is working hard in the right temperature and RH conditions?

I noticed that as well. Obviously the PR/Marketing people don't know about the product.

We can al self identify these days, stick a probe on each ear, then say 'I am a battery' 3 times. Note the readings. Swap polarity and repeat. Can't see any reason my it should not work.

No idea, but I have one of these.

Boarding school, a great institution. Then. My Mother took a third of my take home wage for food and board, was a bargain when I got 30 quid a week, I left home when she started taking 50 quid. She started to drive Mercs in the 1970's.

I heard that he left his heating on for 3 days and all the problems vanished.

The climate in Cornwall is pretty stable, it is governed by sea surfaced temperatures, why we get so much rain, fog and wind. A NE corner of a building (my rear faces that way), can feel quite cool after local noon, SW is a different issue (where I have my bedroom and it is lovely) It is a rare day that we go above 24°C. Have you done a solar gain calculation to see what the overheating risk is?

It is resistance heating. You only pay that once, at todays prices. Heating you pay forever, at future prices. Carefully, and not in front of children.

By using just resistance heating from your PV, even if it was working at maximum output for 2 hours a day, would only give you 8 kWh/day. If you put that same energy into a heat pump, you would get 16 to 24 kWh a day. It all works on the laws of averages, some days you will not get much generation, and other days you will get too much, but with a heat pump you can maximize what you do generate. 150mm of insulation under the floor should be OK, the more the merrier as you don't want to be heating the ground or any air void under the house. Your MVHR will not help a great deal with cooling. MVHR is not a heating system, it is just a low loss ventilation system. When you get your SAP back, it should be easier to design a system that is compatible with your house.

How much insulation have you designed into the foundation. This is quite important, but more so if you do go the UFH route. You may have to halt the build until you have redesigned the floor. Depends on the ASHP, some can modulate down to quite low levels, and a buffer tank can be oversized to cope with the short cycling issue. Very cheap to fit, and if the UFH/ASHP combo has already heated the place up to 21°C, resistance heating can quickly raise it 2 or 3°C more. You would only be heating the air, which has low density, around 1.25 kg.m-3. and a specific heat capacity 1 kJ.kg-1.K-1. There are many different controllers that can now work with phones. This part is really separate from the underlying heating technology. The Sunamp was never really designed to be part of a central heating system. It works by changing phase at a constant temperature, and can be tricky to part charge, especially from an intermittent source like PV. A larger than normal buffer tank with some electrical immersion heaters in it can work pretty well.

Is this for an existing house or a new build one? PV can realistically only supplement heating, not replace it, in a domestic setting. There is nothing to stop you having an ASHP, just oversize it a bit more than normal, and then supplement with some panel or fan heaters. Fan heaters will warm a room up pretty quickly. It is worth have PV anyway and, because of the magic of electricity, the electrons will go to the nearest load first and reduce imports. You can have more than 4 kWp if your DNO agrees.

Cavitation also happens when there is no air. It creates a vacuum 'bubble' which then collapses under the water pressure. This micro hammering causes wear.

Is cavitation a problem with pumps? https://www.thermal-engineering.org/what-is-cavitation-in-centrifugal-pumps-definition/

Any help. www.homebuilding.co.uk/amp/ideas/timber-frame-houses-gallery

Get back to them and ask what the w.m-2 for external wall figure is. 'very low' is meaningless, and misleading. Unlike trousers, you only have to attach them once

Not really. Estate agents measure internally. Not a big ask for them to add some of the dimensions together. As an aside, I thought I would plot the ratio of perimeter to area when increase the perimeter size by 5%. The basic shape is a rectangle with depth twice that of width. This makes the m2 price cheaper for large houses.

It is, and I never understand why people think it is complicated. With a heat pump there should be an air and power chart somewhere in the documentation. Use that to calculate the worse case. General consensus is that air to water heat pumps need to be oversized by 20% to 30%. Not quite so important with an A2A as you can easily supplement with s fan heater.

Yes. You can take a few kWh/day off for DHW. Then proportional the rest by month to give you an idea of maximum heat loads.

I would not get hung up on the electrical grin carbon intensity, we have little influence on that, it is what it is at any given time (and some of the calculations are a bit dodgy). Have you calculated your current heat and DHW loads. This is the first thing to do.

Yes, or I will have to work out the number of naughtical miles till I get home. A minute of arc on planet Earth is 1 nautical mile, at the equator.

I still use cubic centimetres per pound when mixing resin.

Tesla Model 3 is between 1611 kg to 1847 kg. A Toyota Mirai is between 1920 kg and 1950 kg. So hydrogen is not always lighter. Just for comparison, my Ford C-Max is 1527 kg.

We should stop using the old imperial measurements. And all houses for sale should state the plot size, and the building/s footprint size. Then half the confusion about price/m² would just vanish. If we did state things as they are, then we would not have left the EU, or thought that gargling with warm water would stop COVID-19. I often wonder why people are so reluctant to state basic information.

I had a 3 bed house, was identical, in area, volume and shape to the mirror image one, which had 2 beds. So quoting number of bedrooms, bathrooms etc, us not a good indicator of building cost.