JohnMo

If your MVHR fails on the coldest day your heat demand would go down not up. You are in a nearly airtight house otherwise you wouldn't have MVHR. Think logically, MVHR provides the ventilation, it recovers heat from the outgoing air and transfers to incoming air with some losses. If there is no outgoing or incoming air, because your MVHR has failed, then there is no losses, so heat demand reduces. Your installer is less than dim, possibly has no real idea what an airtight house is, or what the MVHR does

I think the oil companies and power generators are taking us for fools. And politicians just useless. Wind, tidal, solar, hydro, biofuel and nuclear cost no more to produce electricity than they did a couple of years ago. Neither does the oil and gas produced in the UK cost any more to get out of the ground and onshore. In Scotland the gross renewables is now equal to 97% of electrical demand. https://www.scottishrenewables.com/our-industry/statistics Gas only accounts for about 10% installed capacity. Buts it's cost dominates the overall cost of electricity. Cost to us has gone up hugely, and the profits of oil/gas producers just ridiculous. Its all stupid

You need to look at the options in person, what looks great in photo, may not really be that great on your project when you look at it or possibly see the price. We did the round and round in circles. In the end went to local saw mill, they showed us a few samples and we just plumped for one, by this time the wife had lost the will to live. We went with vertical Scottish larch grown just down the road.

Install up/down lights at top of wall. Have no lights in the ceiling. They are usually too far from you to be much use anyway. Sorted, make life easy not difficult. No fretting about roof life expectancy.

Fixed price deals for gas are stupid expensive, want 16p kWh, Vs 7.33p paying now

Just fixed my electric with British gas, at 38.3p kWh and 44.3p per day. 1 year deal, so ok to end June next year.

Another thought is maintainability of vaulted ceiling lights, can you get to them once the house is furnished, without a scaffold?

So to clear you have vaulted ceiling, so head height not an issue. The insulation is not in the joists, but between the rafters . Assuming the insulated plasterboard has not been delivered, change the buildup. If the 100mm PIR not fitted. Insulation between rafter dense mineral wool, use whole sheets of 100mm PIR under the rafter. Tape all joints or install vapour control layer. Underdraw with 50mm battens, this will give you space for wiring, slim led down-lights and the control module. Then plasterboard. No holes required other than in plasterboard. The above is way easier to fit well, our between rafters is a pain and not easy to do well.

I think like me https://forum.buildhub.org.uk/profile/8-prodave/ is a self install, so no payment for export.

My Solic200 cost £144. I am displacing gas consumption, and have around 2 to 3 year payback. Not sure why you are paying £500, get the basics, does what it says on the tin, nothing more or less.

Don't think it likely to work on any night cold or hot, as PV needs sunlight.

Top it back up to 1.2 and monitor. Green marks are likely to be areas where the pipe has go wet. Wrap some toilet paper around those areas, go back and look at the paper in a hour or so or overnight. If slightly damp or wet you have the leak.

So what is your CoP?

Took me a weekend to do 190m2, 7 loops at 300mm centres. Had never done it before, used a home made decoiler. Had assistant for one day. Mine was stapled to PIR with my thumb.

Our drive is circa 70m and rises 7 to 8. We hard cored and used crush lime stone. Seems great for cars doesn't move around too much and is pretty quiet.

Unless there a gale blowing the generation is best of nothing, if there's a gale blowing they shut themselves down. Big one are ok, small domestic ones not much use. And still the SAP assessors insist on putting as a recommendation on their reports.

The timer will use 3kW per hour no matter what you PV output is. So if your generating 1kW, you will be paying for 2kWh. The diverter only sends any excess to the immersion. So if your generating 1kW and using 800W, only 200W will go to you immersion.

The actuators are on/off devises, so flow would be either on or off, so each fan coil would be in its own zone, which is not what you want with a heat pump. Your generating a lot is small zones which will lead to the heat pump short cycling. You would use the flow valve to control flow and ideally tune the flow to give the heat output required.

Standard UFH pipes is 16mm o/d. Not sure why you need to run 22mm, unless the fan coil is rated over 3kW?

NE Scotland, 3.1kW with optimisers, 45 degs and SSW direction. Have seen a little over 3kW being generated a couple of weeks ago. But I don't monitor all the time, just happened to at the inverter so took a look

Just took a look at the largest one they do. Production of power will be in the range of 1 kilowatt hour for an hour of 6 meters per second wind for a single turbine. Pretty low output for a 6m turbine.

I counter battened to increase insulation depth, from 250mm to 350mm. But also get rid repeat thermal bridging.

Infra red heaters. Isn't that the same principal used by gas patio heater. And you said it. If your chucking a few kWh at a heater in the open, no what sort it is, you will get no rewards, just a big bill. Heated jacket? Heat you, not the world.

Is it aerosol 2k, professional spray gun isocyanate 2k as they are different things.

That could well be your issue. You need to get rid of the zones, if your smallest zone is the only one asking for heat because the other thermostats have had their demand met, the flow will be too small for the ASHP and it will short cycle. Plan of actions. 1. Have only two zones one upstairs one down stairs. Wiring center will need to be modified, use a central thermostat as the controller. You want all the loop actuators opening and closing at the same time, ideally all staying open. Sort that in step 2 2. You need move your thermostats to say 24 degrees, so they do not affect anything. Slowly reduce the flow temperature 2 degrees per 12 hours until your house (main living space) no longer gets hot enough. You mentioned 19 degrees was your set point. So keep reducing flow until your temp is only getting up to 18. Then increase the flow temp up by 2. degree. 3. Now some rooms will be hotter or colder than others, to increase room temperature your UFH flow needs to be increased, if too cold reduce the flow. The flow gauge on the UFH manifold turn anticlockwise to increase flow. Move it a half a turn, leave it for 24 house. 4. Your thermostats are now to limit room temperature instead of control it, so set those to 20/21. The above should reduce flow temperature, which will in turn increase CoP. Short cycling in where the boiler/heat pump does not run long enough to fully heat up, the heat up cycle is the most inefficient, so short cycling is running for a few minutes, stop for 10, repeat. A CoP of 1 or could be less may be seen.