MikeSharp01

That is useful stuff, I will need another glass of wine to get my head around this little lot. Thanks for putting it together.

I suspect it was the very dry way it was taught, I had done the basic stuff at A level but at Uni it had no applications shown to us unlike the software stuff, mechanical design, electronics & systems all of which seemed to be going places - or so it turned out. I was also somewhat put off by materials science but the good bit of that was, believe it or not, the wood bit - our lecturer had a thing about it.

Thanks Nick - sorry that pic was from 2017, I thought if it has been shovelling stuff up hill since then life must be fun somewhere!

That looks like the soil pipe runs up hill in the white flexi section is that allowed, acceptable, inevitable, to be avoided or what?

But how does that fit with the delta or does it drop out of the equation somewhere and it must also depend on the rate at which you put energy in or does that drop out as well. I can see that if the inside and the outside are the same temperature and you want the inside 1K above the outside then you need to put energy in to get it there and then sustain it. As I have said here before thermo dynamics was my least favourite subject at Uni and I have avoided anything associated assiduously until now. I guess my lack of attention back then is coming back to bite me in the proverbial bum now trying to get my head around all this. I also suspect that @JohnMo will be chuckling and thinking he should tell me just to KISS away the issue and, after all, perhaps we should just build on the shoulders of giants and not try and re-live all the problems the giants had getting there by starting from first principles ourselves.

Ah- yes I get it. I suppose we should be concerned with just one, in that a delta of 20K is, for this property, probably the worst case likely. To flatten that out will need heat input that matches the losses that manifest themselves in the slope won't it. Therefore the slope must, me thinks, be proportional to the heat losses the question then is wether it does or does not make a difference at the extremes and how to derive energy demand from the slope which can then be used with the delta to work out how to keep ahead of it and maintain the set point temperature. I suspect however that I may be putting the cart before the horse here and somewhat over thinking this.

not clear what you mean?

No home assistant as yet but will have when the house is finished, we do have a zigbee gateway available and zwave. I will have a look at the old posts. I suppose my concern was how fast it dropped against the delta. We have, will have, fibre cement tile cladding on the outside, 8t, which will add some heat capacity as will the rest of the plasterboard on the inside 4+t. I need to do some more modelling now I have some data to play with along the lines you and @SteamyTea suggest to get a picture of the losses so I can verify potential control schemes - probably very simple ones.

On Thursday I managed to get the temperature and humidity loggers running in the house and I now have my first scraps of data. The house has no heating running yet so all the heat going in is me working, solar gain and a tiny bit from the logger power supply. I am wondering if the decrement delay is what I should expect, here is the data from midnight last evening to now, (10:46) so about 11 hours. The upper trend is the internal temperature and the lower one the outside temperature derived from the local weather station, about 1 mile from the house. I hope to have my own external one up and running but my PoE scheme out there seems to have a problem. It broadly shows that the temperature started at midnight at about 14.2 and has come down to 13.7 over 11 hours with an outside temperature around 2 ish. Still more analysis to do but should I be happy with that rate of decline? Not sure what i can do if I am not but there are a couple of colder bridges that will be done when the MVHR Inlet and Extracts are fully fitted and there is only plasterboard on about 30% of the walls so far.

I have started down the road with them and they have accepted our heat loss calcs and that their smallest unit will do the job - so almost the reverse of this. the problem now is that the smallest unit is not MCS certified yet - they are working on getting it certified and we can proceed.

Ah - then you know who the installer was and you can pop the name on the paperwork or have I missed something. Usually at that stage they ask you to upload the commissioning certificate within a given timeframe.

We have 7kW of Eurena panels all made in Spain, price is slightly higher but not much.

I don't recall that question on our application, are you using the UKPN online form? I would have said something like this is request for permission to export an appropriate installer will be appointed.

If you build the extension to a high insulation / air tightness / glazing spec 12kW should still be OK but it depends on the % increase in size and where it is going in relation to the rest of the building. How many bugs are you intending to house.

You can just be yourself, you don't need to be an installer, they have been instructed to deal with individuals as well as companies. I just told them my name - all worked fine.