JohnMo

Next thing is rodents. If say under a block and beam floor, I would armour the insulation, insert into 110mm duct and seal each end with fine stainless mesh or wire wool, expanded foamed into place. If it's going to get wet as above also. If it's underground consider doing the same. To stop the insulation being crushed. If it's in a basement say, just insulation will be fine. Then use 25mm wall thickness of what every closed cell insulation is at the best price. I used quite a bit of armacell. Prices vary hugely going into a merchant can be way cheaper than buying in there online shop. Sometimes the other way round.

Weather compensation curve

Can you clarify what you mean by under the floor? Is in a cold space outside the insulated envelope or within the insulated envelope? Makes a big difference.

Possibly the most patronising post I have ever read. Get over yourself and own self importance.

UFH system and fan coils in bedrooms, run everything direct from the heat pump at a single flow temp - around 14 to 15 degs via a simple WC curve.

So heat loss first. More likely the smallest heat pump you can get (around 4kW). Panasonic seem good (I don't have one, but everything I have read seems that way) You size the cylinder is based on the number of bedrooms and likely people living there. Our 3 bed has a 210L. Get a cylinder with at least 3m² coil, for heating efficiency. Cooling - matter of finding which do it. Panasonic do it out the box. Keep it simple, less outlay, easy to run, best efficiency.

So East Anglia doesn't get frosts or snow anymore - me thinks a bit of rubbish in and rubbish output. Computer says... Norwich had down to -5 in Dec and January last winter and sub zero every other winter month. Now add some common sense, average temperature is pretty meaningless for heating design, we also had an average of 4 degs for Dec, but a week where the temps dropped to -9 and barely got above -3, we had the same in Nov and January and March. You design for the likely lowest temp, not the temp that gives you the answer you want to hear.

Try failing a percolation test - we are on sand so water drained away to quickly. Ours is about the size of tennis court. F'ing huge.

We flushed for a few months a few hrs a day, every day on a high flow pump.

They may/will ask for a commissioning certificate - so be prepared

Trouble is it wouldn't provide ventilation anywhere in the house except the room it's installed within. Basically it will supply and extract equal amounts. Leaky house and MVHR is a waste of time and money. Very leaky house (open fire places etc) doesn't really need additional ventilation. MEV and dMEV are for the middle ground leaky houses, not enough leaks to give adequate ventilation, so give slow steady background ventilation, add then the system becomes very efficient, so no-one home in the day the system almost shutdown, and can actually on average, performance just about as well as MVHR.

dMEV and MEV use the principle of cross ventilation, if you do not provide either trickle or other vents in dry rooms, you may as well not bother, because it does not work, many studies have shown this. For most efficient operating you need moisture activated vents or auto vents, also limit householder intervention or closing off vents. Both of these can close down when that room doesn't need ventilation - such as a bedroom in the day or living room over night.

There's your best but of advice.

If you read building regs for a workshop or garage the ventilation required is huge. Because it assumes you will be driving a vehicle in there and it needs to get rid of fumes etc. But moving on You are mixing two different reasons for ventilation and stopping ventilation. Insulation and building fabric - you are trying to keep moisture away from the building fabric, the moisture as it passes from inside to outside can condense back to water within the building structure and then over time lead to failure of the building structure. Ventilation, is there to keep humidity and co2 at below a threshold where is not good for human health or the building. Ventilation is a necessary eval, you heat the air and bring in cold - the more you seal the more you have to replace with mechanical means. Old building leaked like sieves so didn't need additional ventilation, air was lost at a huge rate you just didn't notice it.

Remember to factor in with your deliberations, no MCS cert, you are unlikely to get any export payments. I chose to forego them, and export very little. City Plumbing us also very cheap. 410W panels £47 plus vat.

Just make provision or install panel heaters, with time and thermostat control, cost to run isn't a factor if you have no interest in switching them on.

£16k is a lot of money. £16,000 / 700 is 23 years payback on exports If you accept all 4500 kWh and £700 export is generated. Not sure what you currently pay for your 4500kWh at 20p that's £900. 16000/(900+700) is 10 years. If you are managing to get your average down to 15p with your tariff it's £675 a year, and still about 10 years.

Why not, you have all the tools. Your coldest temperature, and the heat loss at that temperature, you told us earlier 2.5kW @ -10. If that temperature over 24 hrs that's 2.5x24 and is 60kWh of heat required.

Wire brush the old paint off, should come off easily. Then paint in high zinc content paint, often sold a cold galvanising. Not cheap but will last another few decades without being touch again.

Exactly? Maybe he going to insulate it with a magic substance, that means paper thin walls, total silence, and no heating required. And costs pennies to build. That would be unique.

I thought I was getting OCD doing once a day - so stopped now do it twice a month. But saying the above, now have a heat pump monitor system coming with segregated CH and DHW. Every statistic ever needed - I think

I started with gas boiler and some heat meters came up cheap on here. So installed and played with flow rates Andy temps to get house comfortable (it got down to -9) it also confirmed my heat loss calcs were pretty much as predicted.

Heat pump you really should be running steady state, not on off like a boiler. I take the following for DHW allowance. 2.5kW heat demand x 24 hrs is 60kWh. So now you need to take time out for DHW, so allow 2 hrs (2x heating sessions). So now you need to produce 60kWh in 22 hrs. 60 / 22 so 2.7kW. So you are looking at a 4kW heat pump, which is about as small as you get. -10 is excessive for Suffolk, but in your case it's going to make much difference, you will still have an oversized heat pump. So you need a single zone to enable it to cope with limited cycling.

What you are showing is a complete rip off, buts not from City Plumbing heat pump builder. For one they are just a wholesaler, so would not be doing a survey or taking your old stuff and recycling nor doing install. I plugged in the parts on your quote and including all the secondary circuit and buffer etc, which can all be deleted, it came out at £3700 plus vat. Only bits to add were pipe and insulation.

Start with the basics, so you understand where the calcs come from. https://www.open.edu/openlearn/nature-environment/energy-buildings/content-section-2.4.1