SteamyTea

Stick to building regs https://www.planningportal.co.uk/info/200135/approved_documents

No, but I do live on my own, but 5 adults in neighbours house and they seem clean and tidy. If I needed more hot water, I could fit a larger cylinder, cheaper than a new boiler. Read my rely about the flow rate, it is enough to run two showers as it is, easy to fit another pump to run more, but I would be running out rooms to fit showers into. How well does a combi boiler work in a power cut. At least I have some stored hot water, definitely good for 2 days, probably 3. The flow rate of most, cheap, combi boilers is pretty pitiful. Had one in my old house and it took 15 minutes to fill the bath. This is pretty pointless really, you do not understand, and cannot be bothered to learn the differences in the technology, you just have a very backwards view on heat pumps. You assume they are low powered, only low temperature, are super expensive to buy and install, while any gas combi boiler has infinite capabilities, gives 100% reliable service, costs the same as a week in a Travel Lodge (do they use combi boilers in hotels?) and produce less pollution. I am not going to change your mind, but I will pick you up every time you say 'they don't work' or similar, as that is just nonsense, and I have no tolerance of people that talk nonsense.

200lt in this house. I can also get a flow rate of 20lt/min if I want. (I don't have an ASHP but the arithmetic is the same)

Limitless, like it never, ever runs out?

I could have had mains gas fitted back in 2005, was going to be £20k. Divide that by 16 years, £1250/year. So that is 3 times more than what I currently pay in electricity. Not only do I get plentiful hot water, I get lighting, cooking, radio, clothes washing, IT services. I wonder why we don't have gas lights any more, they should be the cheapest form of lighting.

So half way there then. I was answering you uneducated assertion that a heat pump can only supply 5 minutes of hot water. Go and read all 3 pages of the thread and see what it is about before spouting your usual nonsense about heat pumps.

I am saying that they can supply as much domestic hot water as you want. You name the quantity, I hall find a solution for you.

That is the only true statement in your reply. It is thermodynamics. Show me the data that they cost 10k and only supply 5 minutes of hot water? Or stop talking nonsense.

Do they have lower CO2 emissions? Should they have an annual service? If they are in a rental, do they need a safety certificate? Can they be easily installed by a 'normal' home owner that can do DIY? Do they need a dedicated supply and meter if one is not already installed? How do you proportion the meter rental? And the big one, if no mains gas is available, are they still suitable? You really do not like heat pumps do you.

Yes, you get 'clumping'. Stratification does not really happen, more a case of a spatial-temporal changing temperature gradient. There is probably good reasons they are not common.

Am I right in thinking that while oil boilers can condense, they do not modulate their power?

That is because of the relatively small external wall area as a ratio to to the whole area. Changing the floor U-Value, when using UFH can have a much larger impact, the delta T is so much greater.

I have had a few jobs queried because of this. Charge one price to put a hole in, and another, sometimes higher, some times lower, to not put a hole.

May have come from comparing heating degree days distributions. If I look at a 2°C difference in my HDDs, I get a 20% difference. Not surprising as the weather is very variable on the coast.

Not gone though the whole list, but I don't think the specs are hitting the current standards. If that is the case, then sack your architect.

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.