JohnMo

Swop your current accumulator for some thing like this https://www.anglianpumping.com/product/pressure-vessels/300-litre-accumulator-vertical-gws/ Maybe 2 or 3 of them? Actual storage capacity of 300L version is about 150L the rest taken up by bladder and air space.

Your other option This is an accumulator, there.will be a no return valve, between the pump and it. So even without pump on it remains pressurised. So your other option is to replace this with a bigger or several bigger ones. You have a pressure maintained water supply for normal use, it passes through your filter system as normal. Pump fails nothing changes you continue to get filtered water. You could add an alarm - if pressure remains at or below 2.9bar for x minutes send a notification to your phone.

I don't have a storage tank at all. Just a 100L accumulator. For main grid down periods, I have a whole house battery, PV and if all else fails a generator. If pump fails So really didn't see the point of a big storage tank. Unless you constantly change out the water not sure how healthy it would be. In a power cut your UV filter is off, so no long drinking water anyway. If pump does fail, we have bottled water just in case. Our first pump failed after month and that got replaced in 24hrs.

We have carpet and it really kills the performance of the UFH. Best advise is not to let the other half or partner anywhere near the carpet shop. But will have your head on a platter when you choice the best stuff for UFH, because it's not got a luxury feel. My go to advise now is really don't waste your time and money on bedroom UFH. So Tag target - is as low as you can get away with.

Unless you are a 1 bedroom house 150L is too small really. Just on to Cylinder2Go @Nickfromwales go to place they have 3.3m² I believe. I have an Ideal slimline 210L that is 3m².

No immersion should not be involved. Your cylinder is heated slowly over about 40 minutes, heat pump output temperature slowly increases over the heating period, you should be getting a CoP of about 2.5 to 3.5 depending on heat pump and outside temperature. Your UFH should be getting a CoP of 4 to 5, maybe 6 at times, that's the difference in high temperature flow and low temperature. This is mine from the other week. The big peak is DHW heating, the other sides is UFH. The red is flow temperature and green return temperature.

You just need a unvented cylinder - nothing more nothing less. Make sure it's sized for the house and has a big heating coil 3m² or bigger. The heat pump will switch from UFH to cylinder heating via a 3 port change over valve controlled by heat pump. At the same it will bump up the flow temperature.

Heat system comments 8kW heat pump, so will a flow rate of about 1.5 to 2m³/h will be needed, 25mm pipe sounds too small? Have you done a pressure drop calculation, using the internal bore. Why do you need the volumiser? You rarely need a volumiser on UFH as the floor (concrete or screed) will absorb heat very well. Especially if running open loop. Why do you need the check valve on the return to the heat pump? Your expansion vessel and pressure relief should be there. So it's after both the heating and cylinder return.

WC curve is pretty straightforward, use you manual to find the correct things to change as far as settings Curve start at 20 Deg outside set to minimum flow temp to 25 or minimum allowed flow temperature. At -6 outside for radiators set to 45 and UFH set to 35. That's a good enough start point. Now wait for the heating season to start. In rooms with thermostats set to max and with radiators thermal valves set to max. Also set all timers to run 24/7. Then let system run for 24 hrs, if overall house is too hot reduce the flow temp at -6 down, only adjust about half the overshoot, so if target is 21 Deg house and it up to 24, reduce flow by 1.5 degs. other way if too cold. Only adjust once each 24 hrs, until you get where you need to be.

They make nothing out of it, I paid the guy direct, the princely fee of £40.

What venom - your a happy soul! Worked for me, works for the company I used, that's all I can say.

That's easy, you do external insulation and clad. In fact that is way easier than what I did.

Just use this then, your way over thinking. https://www.ecodeck.biz/plastic-shed-bases/

This is how I did mine https://forum.buildhub.org.uk/topic/31017-summer-house-insulation/

Especially if it's timber 6.8m long, saves loads of messing about.

Why bother digging down at all. Just do the same as a garden room. Plastic grids filled with gravel, or slabs set on concrete are options. As well posts set in postcrete. Then build up from there. Pre designed and supplied as a kit garden rooms are great value, the 70mm thick ones are very robust. Just add insulation.

So actually pay for a skilled work force? But isn't the skilled worker buying the materials, on top of this? They should know what they are buying why.

We have a Heta Scanline. It does .

I would always get a stove that took external air for air for primary and secondary air. Otherwise you are heating air then it's being sucked back in to stove as combustion air and cold outside air is being pulled in. Another thing I have found is stoves with plenty of soap stone give off a much more steady flow of heat, slowly heat up, steady output and then slow to cool when fire has stopped.

You may be a doubter, but it was a condition of my well being bored. No water diverter, no well. Company has a near 100% success rate. The guy came around within 10 minutes stated exactly where to drill and said when we would hit water at x metres, and that we were to ignore and continue to get to main reservoir. Was spot on within a metre depth. Also friend is developing on old site which had private water, spent a week trying to find well, water diviner had it located in less than half an hour. From my limited experience it works. So why knock it?

I would build, pretty similar to what is done locally, the skill sets are readily available, materials are normal to those using them

Get a water diviner to tell where to locate well or borehole. You need it where the water is, it's not likely to be where you want

Welcome Heating UFH in main areas, would do fan coils in bedrooms. Design to run for heating and cooling unvented cylinder. ASHP to heat and cool. Ventilation If you go for a good airtightness MVHR (airtightness of 2 or better), otherwise conditions based MEV or dMEV with humidity activated trickle vents. High ceilings - YES. We have vaulted ceilings all room they are great. NO to both. I would either do twin stud timber frame, with either cellulose insulation or rock wool insulation, ICF or block work with big cavity and poly beads insulation. Bungalow have a poor form factor, which means they need way more insulation to have the same heat loss as a good form factor (a cube shaped house), so U values - floor aim for 0.1, walls better than 0.14, roof 0.14 or better. Glazing, triple glazed. Fireplace no, stove with external air for primary and secondary air.

Think you have two options 1. Rip it all out and do it correctly - may not be easy unlikely to be cheap. Could grow arms and legs, from a planning perspective and construction scope. 2. Do a good thermal underlay and good carpet. Pretty cheap, a warmer feeling to the floor, very constrained work scope. If you are concerned with damp, you could do a liquid DPM, which is basically epoxy paint, paint one day underlay and carpet the next. Option 2 and move on with my life, would get my vote.

Is a viable option. An example of a 40m² garden room (first I found), could easily be configured to be suitable, add insulation and heating to make it usable 365 days. https://summerhouse24.co.uk/large-garden-office-hansa-ii-40m2-70mm-4-x-10m/