JohnMo

Big question - do you need the Energy Integral? Does add to system efficiency or house comfort? Suspect the answer is maybe or sometimes. But generally a good marketing tool, has kept this thread talking about it for a few years.

I would and try and log electric data and actually work out costs, then switch off in the expensive period and again work out costs and compare. You may see very little difference most of the year, you may see a big difference depending on your house.

Yes it would. WC really doesn't need anything in the house except a balanced heating system. That's the thing with weather comp, it doesn't need any more info, just outside temp to set target flow temperature against the defined curve. In fact all the boiler is interested in target flow temperature and return temperature. It then modulates output based on management of dT, it doesn't even even care about flow rate unless it actually modulates flow rate.

Isn't that just 4pm to 7pm, so only 3hrs, not 16hrs you have programmed to be off?

I would strongly suspect a lot of your issues are related to setup and operating. Rather than anything else. Would bet your immersions are doing a lot of the work instead of the ASHP. Tell us more on your set up and how you operate it? Weather compensation continuously, thermostat(s) and set temperature, on and off via a timer. UFH, radiators or a mix, buffer or no buffer etc etc Doing a hybrid set up is pretty straightforward. Radiators in front of the ASHP, sound like a lot of energy in (gas or oil) and not a lot of gain in heating energy.

Or leave them as a placebo devise, just don't have them connected to anything functional.

Was saying this instant, I was implying when it is working.

Or just delete them. Just run WC. Put normal TRVs in bedrooms. If you have radiators randomly switch on and off you just end up short cycling the boiler and undo any savings made.

Even though the times are set, is there a thermostat overriding, so during the none heat periods if a thermostat still believes its not warm enough is it still making the system run? The other issue you will have on cosy, with a heat pump sized to match your house heat demand, is the heat pump cannot deliver 24 hrs of heat in 8 hrs. So if you have a heat demand of 5kW (so 5 x 24 hrs is 120kWh required in 24hrs), you need a 15kW ASHP (so 15 x 8hrs is 120kWh) for Cosy to work at design temp. Or have a battery to allow the heat pump to run during expensive times.

WC normally has the circulation pump pump running 24/7. Room stats are also either deleted or set a few degrees warmer than room target. Maybe the circulation temp is above the set point controller hysterisis. That's the thing with WC, it's not always heating, mine spends most it's time just circulating. Add heat for 20 to 40 mins takes a few hrs off. As the day gets warmer the set point for the water lowers so the boiler or heat pump doesn't need to add heat. If in doubt switch off for a few minutes and switch back on. Sometimes lots of setting changes just confuse the controller and it's needs a reset.

I would airtight layer under ceiling joists, counter batten to form service cavity all wiring in service cavity, down lights in plasterboard. 50mm cavity will leave room for led transformer also. Plan to have no wires in the loft. Not ugly, airtight and insulated ones are also available. Can you do it so the plenum for each room penetrates as easier to seal-up. Tyvek Supro BBA certificate mentions a drying out procedure to be followed during first heating season. So perhaps dig that out also.

Just what we did, vaulted everywhere except one area, that became plant room come store room. Big loft hatch with integral ladder.

The other way and in my option better, is make the loft space warm. Insulation is then done at roof level.

Flooring manufacturer instructions normally give explicit instructions. Ours had to be glued down on top of UFH. Doesn't mean yours will. If in doubt ask the supplier.

The window really needs to straddle the insulation Some notes on here https://nhbc-standards.co.uk/6-superstructure-excluding-roofs/6-7-doors-windows-and-glazing/6-7-3-in-service-performance/#:~:text=In cavity masonry walls%2C doors,layer of the external wall.

I would consider EPS beads, they will self drain any water away and gravity will fill any voids fully.

What's going inside the house or within cavity with respect insulation? Ideally the window should straddle the insulation

What does your installation manual say on the subject?

But not if you have hot water circulation. As there are issues with very hot water making its way past the TMV. Couple of simple ways to mitigate 1. Just set your tank temp to 48 to 50 degs, then no need to have a TMV at all. 2. If you have a mixer tap on the bath this issue should be taken care of by the mixer.

That was the way I calculated it all out also. I used engineered brick on top of thermolite, good for fixing too. Our screed is 100mm concrete, so the thermolite block starts above the screed to insulation interface. So the no thermal bridges. All our internal walls are wood stud walls. We left an air gap either side of the acoustic insulation before the plasterboard.

Not jumping in to your question. But make sure heritage has actually seen and approved stuff. Even with planning in place, doesn't mean they have approved anything. They are normally engaged separately. Been there, been bitten.

But the point really is you don't wait until the house is up to 30 degs before, you say let's switch on the cooling, like heating it's better to keep things at a even temperature. The house then sits at say 23-25, not in the 30s. Example, 2 August for us, had an external humidity of 74% in the afternoon, we get all our heat from solar gain, left unchecked the garden room (fan coil) will easily exceed 30 degs. Cooling was left to run on weather compensation. Max temp reached in room was 23 and max humidity was 52%. So dew point was 12.6 degs. If I left the temp to rise to 30 and humidity remained at 52% the dew point jumps up to 19.1 degs so you have condensation issues.

Do you really need it. Switch over from DHW to UFH a couple of litres of hot water pumped into the 35T of concrete. Zero effects. Plus your mixer will always add a minimum of 5 degs to your flow temperature as they always mix flow and return irrespective of mixer settings. Looked at the installer manual, have selected the scheme to match your install, noted there were loads of options available?

You really should look to simplify your system. Questions Do you have a buffer? If so is it temperature controlled by the heat pump. If you don't have a buffer all your zones are going to cause you a bunch of issues. Notably short cycling if you only get down to a couple of small circuits. Do you have a mixer and pump on the UFH manifold?

If you can charge a few times a day, you just need to look at the likely usage between changing. Then pull together a spreadsheet to compare running cost to capital cost and do what makes sense for you. Most dominant period is winter. Most simple is AC coupled battery. If you add solar later it all still works.