JohnMo

That must the biggest tangent from the original question ever.

Think you would need an off grid inverter to switch over to. Other may have a better answer.

Would really do a Nick advised or as it mild turn the flow temp down at the manifold temp regulator so all loops flow cooler. Down to 30 leave your thermostat and time as is, the next day bump up temp 5-6 degs, then after another 24 hrs set everything back to normal.

Maybe true in very hot climate, but then only for a short period in the hieght of summer at midday for about an hour or so. Really I would worry about it, 95+% of the time it's not an issue even in the summer.

Ours are rechargable (every six months or so). Remote control, will do any one on its own or all together. Can control 16 blinds from a single remote

Aerated are fine, but it's just a matter of using rawlplugs specifically designed for aerated blocks, rather than random plugs, which split the block.

Our structural engineer missed the inner support for the lower part of the roof. There is a support from the portal frame to hold up 2x 450mm glulam beams. Neither the architect nor the structural engineering had any details of the shown on any drawings. Ended up designing it myself, steel fabricator came back and site welded it together.

We don't have big sliders, but nearly all our windows had the frame installed first then the glazing. Because of acces and weight.

That's a bit cheap for a multi thousand £, piece of equipment.

Looks like a bit of cut and paste engineering which hasn't captured all the changes needed. I would ask him to clarify.

I would do the insulation in the floor, but personally I don't believe there is enough insulation going below the UFH to make cost effective to run as the downwards heat loss will be large. So would either increase depth of insulation or just stick with radiators. You can get a couple of nice radiators for same or less cost.

Gas at 10p is £1650, energy in to house 13200kWh HP at 3.5 CoP 1320/3.5 =3771kWh 3771kWh at 34p is £1282. Best part of £400 a year saving

The temperature sensor can be remote from the fan unit, it's normally a small box 75x75x25mm sort of size. This is my temp sensor the small white spec. Your fan unit does need maintenance but not the temp sensor.

There is no maintenance

Cable length can be quite long - so shouldn't be an issue extending the cable length. Sun on it is no use, will make WC uncontrolled, which wont help you. Relocating it, is the only way to fix it, relying on plants isn't a good fix. Over or under reading consistently, isn't an issue, as you will be fine tuning the flow temps and curve when you commission.

Question how do you operate the floor at the moment, on a timer and thermostats? How long do you have the UFH on for?

If you save that much your heating bills must be huge or there was an issue with the old boiler or system and/or you have decreased the heat loss.

Section of my structural drawing attached. The 140 thermolite was changed to 100mm, as at the time there were no 140mm wide ones available, insulation width increased. The screed depth was also increased to 100mm, as without taking 35mm off each block the stub wall buildup didn't work out correctly.

Spend last year learning about our building inertia when heating, and fixed a couple of issues with the buffer plumbings. So now the boiler (min output 6.7kW), keeping house at an almost constant 20 degs. UFH flow temp is 23/24 degrees during the day, boiler kicks in for about 10 mins every hour or so. Night setback starts at 1830 hrs and goes back to day setting at 0230 hrs. Working pretty efficiently, on average using 19kWh per day for 194m2 house including DHW (about 5kWh) Against a theoretical 26 kWh for heating only, at our weather conditions using Jeremy's spreadsheet. If I was heating with a heat pump with a CoP of 5, that would be 3kWh a day for heating only. Super cheap.

You would have to compare that with direct electric heating. To get a pay back time. So direct electric heating has 100% efficiency. Say gas is 85% efficient. Gas effective gas about 12p, electric 34p Then it depends on central heating cost to install compared to panel heaters at the cheapest, or cost for UFH with immersion heater. Plus DHW heater. And how much energy you use. So for a like for like comparison system boiler, and UFH and hot water cylinder £600 -1000 for a boiler, immersion for UFH £60. So say 10000kWh per year. 0.12 X 10000=£1200 0.34 X 10000=£3400 So in that case not long even with an expensive boiler. A combi gas boiler would delete the cylinder, so pay back shorter again. As it costs an extra £2200 per year to pay for electricity. In this case even comparing panel heater to full blown central heating, pay back is a year or so. 20000kWh £2400 and £7400. Very low user 1000kWh £120 compared to £340, so a couple of years. Economy 7 changes the maths, but you have to also pay for storage heaters.

If you can run Weather Compensation, do you need a room thermostat, just balance the flow rates to get the room temp you require. If you have thermostats in the room, use simple ones to call for heat, but use them as limit stops, instead of a thermostat in the normal terms. So if the WC is set to give you 20 degrees, set the thermostat at 22.

Not really, as gas is not 100% efficient, most gas boilers achieve around 85% efficiency, especially if not run on weather compensation as a single zone. So you need a scop of 2.8 to match gas.

You basically in theory should start at at flow of about 25 and every 24 hrs increase the temp 5 degrees until you get to 45. If you are well insulated, your flow temps should be low. Our max flow temp is 28 at -5 outside. So I just started it up, plus our concrete had been on place for a year or more.

At the moment you have a nice thermal bridge, I would also be concerned about condensation forming at the sole plate. I have a typical Scottish strip foundation, with blockwork coming up from the foundation. I modified mine with full structural approval. Slightly different ICF build but the principals should be the same. Your soleplate fixing could no longer be central, but be staggered between the inner and out blocks. Total width 365mm Inside block 100mm thermolite Cavity filled with 100mm PIR - size to suit width required. Outside block 150mm concrete block. Inside all that I used a 70mm PIR upstand from the floor insulation, inside that is concrete screed 100mm deep.

Not really believing you are doing this without structural engineering input. Or if have it, not following what they are saying to do.