JohnMo

Statistics and numbers are a wonderful thing. I've always said insulation is king but this does put a different spin on things. Not sure this approach would apply with a suspended floor, as it's outside air cold underneath. But as with all statistics you have to be careful. Also note it is extremely likely the floor was then screeded, not the same as a foam former covered with OSB, heat transfer from pipes was good to the floor the way it's been done. CoP and energy use are related, but very different. Running low flow temperature with a heat pump yields a good CoP, but doesn't mean the energy yield is all used. Insulation means more energy input can be utilised in the house and less escapes. Think in the video he said the heat loss was about 3kW at -3, assume 25% of that is floor losses, so about 5p per hour (CoP of 4) but only when it's -3, less than half that at 7 degs. So justifying ripping floor up to insulate would be low. Good result for CoP, but maybe not so good for energy utilisation. But a cost effective solution overall. Just a matter of number balancing.

That sounds like hard work, hadn't planned that today. Wife has left over french onion soup for her and I've got left over Mac n cheese to eat.

That's what I like about the titon units, super easy to adjust, normal rate adjustment by individual flow and return potentiometers, same for boost. Setback just falls midway between current normal setting and min acceptable flow. Had a look at Titon frost strategy for cold weather without input heater. As it senses heat exchanger frosting is likely to occur, it starts to slow the supply fan down, once temp is outside frost zone it starts to slowly increase fan speed. So over a prolonged cold period supply fan will cycle speed up and down slightly. Only part of the story You need a low pressure drop over the system, to get fan speed as low as possible. But the MVHR also needs to be generally quiet also. But you also need the supply or extract terminal to be open as far as possible to reduced localised noise generation. But also have system balanced. That is part of commissioning, you can model noise as much as like, but poor commissioning will lead to a noisy system.

Combi - they aren't flushing the toilet, running taps elsewhere, got the dishwasher on? That would be my start point.

There is a thread from about year ago, someone did something similar and one part of the floor was great the other rubbish. The different heat profiles although small, had an impact on the system worked. At very least you need to ensure each floor type has its own UFH loops, so the loops do not have to work in both areas. Then you can balance the flows to get the system to work correctly. Do not try to mix radiators and UFH in the same area, you will have two systems with very different inertia fighting controls. Your money, your house, opinions given as requested. KISS (Keep it simple stupid) is the best policy for heating systems, zones and mixed systems are normally worse, not better performing.

Not if anything on this video will help

That is tiny amount of space inside - loads of work and possibly money, that will get skipped in a years time because it's so small.

How are you going to maintain the French drain? How are going to render? Why do people build so close the boundaries. Just move to the correct house. PIR insulation is the worst insulation for a cavity wall. Easy to make a bad job of it, difficult to get a good job.

This is a different take to the UFH argument. But you will need to run 24/7 to keep floor buffered with heat. Which is how you should run UFH really.

Diverter is working well. Generation today was 22 kWh Export 1 kWh. 210L cylinder heated to 71 degs (8.5kWh), which the max I get out of the immersion. Buffered 27.4 kWh of energy into floor via ASHP with the heat pump running continuously for 5 hrs. At an average of 4.8 CoP.

Why are doing free standing and then building in? Other than that I am lost with your explanation.

A radiator is a radiator, takes its output at T50/T60 from manufacturer data and then use the correct correction factor, based on actual flow temperature you intend to use.

I think I would make life easier for myself, nice radiator or two, maybe plinth heaters in the kitchen. Doing UFH well with multiple floor make ups isn't easy. Wunda etc. will sell you everything but doesn't make it a good or cost effective solution.

There is a dedicated thread for this - would seek it out and ask there.

I was told by the architect that ground screws and permanent building are not compatible. Reason being, the design life of the screw is way shorter than the building. So the screw will fail first, which isn't good. Trouble with a structural element that can corrode being in contact with the soil is the corrosion. Soil can be acidic, alkaline, wet, and there is lots of oxygen present. Without very careful material selection you will have issues down the line. Put in normal foundation, make sure its well insulated, sleep soundly not thinking about issues, that may occur in 20 years, that cause the extension to fall down. Screw piles have their place, for sheds and summer houses, which are not permanent buildings.

Rapidly coming to the conclusion that WiFi and home should be disconnected. Use WiFi for the TV (although I use ethernet cable) and computer and that's about it. If you want decent security, you need a proper system and to dip in to a deep pocket and have it professionally installed. Have it linked to the police etc.

Over is the easiest to do, but if not careful can make roof look a bit clunky. But you still need to insulate at the outside wall to bridge between wall and roof insulation. Between - Any solid insulation such PIR between is a bit of a non starter. How do you go between the metal webs. Blown insulation, tried to cellulose but they wouldn't do it for some reason. My roof is similar, I did counter battens spaced away from rafter 50mm to drop ceiling down 100mm, to give 356mm cavity and spray foamed. Then a reflective vapour barrier and 50mm service cavity then plasterboard. Drape the vapour membrane onto wall and use airtight mastic/glue to stick to wall or tape if a membrane.

Eufy do solar powered cameras not sure about Poe? I have their door bell, and door sensors which all work as advertised. Door camera is easy to install, can be battery or normal door bell powered.

That's a lot of money. Definitely just leave as is from builder for now. See how it runs. Boiler supports weather compensation out the box. So I would move to this with radiators. You may need to change the odd radiator to get system running a nice low temperature.

Maybe a little noisy?

Maybe a hole in the heat exchanger or a petrol leak? I had one also. Definitely got a more than 25mpg. But yes things have changed. My beetle has also changed over the years also, owned it for 36 years and 25 years old when I bought it. Now has a space frame and Aprillia RSV 1000cc V twin engine, and doesn't need heating anymore.

New build well insulated with upstairs - do you actually need UFH upstairs or radiators? Many have nothing other than the provision to add electric rads if needed. If you have a heat loss 3kW for downstairs and 2kW for upstairs, just size the UFH array downstairs to kick out 5kW. Upstairs heating provision added. Fully compliant with BR and MCS for heat pump install. Put electric heating mats in bathrooms upstairs. Are you just making life difficult?

Granted, but coolant flow cooling needs to be done, so just making use of a waste product. PHE instead of water to air HE. Exhaust cooling needs some control, but no different from a VW beetle and air cooled Porsche which used exhaust heat exchangers and blow air through it for vehicle heating. Just blow through exhaust heat exchanger and point the warm air in the direction of the ASHP fan. Just have to be careful you don't mess up the exhaust scavenging effect, by extraction of too much heat.

Don't be fooled by advertising. It mostly bull sh** to catch you out. If a house needs 6kW to keep it warm it needs that regardless of heat source. Ripping a new house apart is just expensive and a waste of time and effort. If it's an actual new house they have to install a low temperature radiator system anyway. So check they have are doing so. Ask questions about how it's installed Is S, Y, X or W plan? Or is a combi boiler? What make and model? Post the answers. You are likely to line Wunda's bank account, empty yours and gain a big fat zero on running costs gains

That would work.