ProDave

Did the plumber make any changes to the plumbing like different or extra expansion vessels, pressure reducing valves, over pressure valves etc?

This bit requires some joined up thinking. For my house max overall energy would be limited to 6000kWh pa. To match that with solar PV would require probably 8kWp of solar PV. While I would have no objection to installing that much, the DNO may have other ideas. I already know for just 1W over the 3.68kW allowed by default, there would be a network upgrade charge, and there is no guarantee that they would even allow 8kWp of solar PV. So if that sort of requirement is going to become normal, then it also needs to become normal that DNO's will accept that much without punitive upgrade charges.

I thought stone chippings were used on mineral felt roofs as a way of protecting them from UV. Do modern roof coverings need that protection?

About 6 years.

The 2 pack vsarnish had some odd restrictions on application, something like each coat must be applied no more than an hour after the last coat otherwise you then had to wait 25 hours? We gave the underside 2 coats, then next day turned it the right way up and gave the top 3 coats. And spilled red wine does not bother it either.

I will have to look that up. It's a pair of contacts on the main ASHP not the controller, and you have to enable that with one of the DIP switches in the control board. Do you have the installation manual for the HP itself, it should be there, if not I can photograph the relevant pages of my manual.

I have a 5kW version of the same era with that same controller. I concluded very early on that the controller was the most illogical thing known to man and there was no way the average "man in the street" could program that and set heating schedules etc. So mine is controlled from the "room thermostat" input and that connects to the UFH controllers and a perfectly normal central heating time clock that everyone understands. So I don't even bother to set the time on mine, let alone anything else. So I honestly can't say if forgetting the time and mode is normal or not. The main thing for me is, do any parameters that you have customised remain after a power cycle? THAT would be a right royal PITA if they all needed resetting after a power cycle.

I am the same. I like to be doing things. The only difference with retiring is you are doing things that you want to do when you want to do them rather than what someone else wants on their schedule. The problem comes when we get a cold snap like the one that has just finished. There is not much inviting about going outside to do anything and I quickly run out of things that need doing inside. Now it has warmed up I have no shortage of things to do. As for multiple builds, 2 is enough I have no plan for another one. I still have the car port and the posh shed to build to "finish" this one.

It IS possible for us all to be warm BUT the capital cost required to do so means it is not going to happen. Even with the high electricity cost at present, my house in the Highlands uses not much over £300 per year to heat it. I can only speculate how low that would be if I had built the identical house in a less cold part of the UK. If every house was that efficient, then most people could afford to be warm. But there is no way many houses will get anywhere near that any time soon. But what angers me is there is no reason why ALL new build houses are not that good already as built. Honestly the cost of doing so in a new build is not much and build time is the optimum time to insulate it properly and make the right choices like low temperature UFH etc.

If I am understanding that correctly YOU paid a BUILDER to build the extension and you still owe the BUILDER some money because he thinks it is finished. The BUILDER chose to employ a CONTRACTOR to do some work, and they did not do all that was needed, such as the insulation. Get your BUILDER to come and look at the examples you have showing the missing insulation. And since your contract was with him, tell him it is his responsibility to correct the omissions, and once that is done to your satisfaction, you will pay the final bill.

Our Oak worktop is varnished with 3 coats of Howdens best 2 pack varnish. Apart from where one visitor scratched a bit slicing bread on it (not on the chopping board) the rest is fine and just wipes clean like any other worktop. Save the oil for doors.

The last government doubled the price of electricity. And got away with it. Oh wait, they are no longer in power, but I doubt that was the only reason.

So now +12 today, 24 degrees higher than last weeks low. Today was the first day since Christmas that the hosepipe was not frozen, so both cars cleaned today to get some of the grime and salt off them.

When mine (different make) started to seem non optimum, investigation showed the stainless steel inlet vent has a Gauss filet on the input that had become almost entirely blocked with dust. Cleaning that out restored normal operation and is now on my annual maintenance list.

What worktop? Anything other than a simple straight run, I would get a trusted joiner in to cut and do any joints. That is just what I did with our island, a joiner I know and trust did a very good job of all the cutting and finishing of the oak worktop, far neater than if I had tackled it myself. Likewise the main worktop was stone on on supply and fit contract.

My only thought is you will discharge the battery you are connected to, so they will end up imballanced. So connect it with large croc clips and periodically move it to the next battery so they all get discharged just a bit until you get the main inverter / charger sorted.

Excellent news Jeremy. The 0.5L expansion vessel you mention seems tiny? What is that for? That won't take up much expansion of hot water. Compare that to something like a 25L expansion vessel on a typical UVC and even the closed UFH circuit in our house has something like a 10L expansion vessel.

Chances are, a lot of the "damp" is condensation due to moisture in the house hitting cold walls and possibly not enough heating in the house or ventilation of the house. If you dared to ask a "damp specialist" then of course they will say it is damp and give us lots of £££ to fix it.

Those figures would leave me with very little confidence at all

Is that not a WEE responsibility for the manufacturer?

Nice to hear from you again Jeremy. In your absence a few other people have had failure's with sun amp's and inability to get them fixed in any way. This has left some of us thinking this is a promising technology let down by in many ways poor design and certainly not been designed to be servicable in any way. Compare this to a stainless steel UVC and an immersion heater. The heater is an easy swap that any plumber can do, the expansion vessel likewise is servicable and the tank itself rarely fails and usually has a long guarantee. Given the potential to fail, and then it's irrepairable and out of guarantee, then you really really really have to want a Sun Amp to tolerate these issues compared to an UVC.

The planning system NEEDS to be streamlined to scrap all these reports about newts and bats, complicated and unecessary conditions etc. ALL they do is result in exactly the same building being built, but at extra cost and time to the applicant and extra work for the planners. All at a time when the planning system needs streamlining to make it quicker and more efficient and pass more planning applications quicker.

THAT is the bit that is so wrong and would be so easy to correct. No wonder the cheaper generators are making big profits, because the system over pays them, making people talk about windfall taxes to punish them. All that is needed is change the way the market works so they all get paid a fair price for what they generate but not excessive, and no excessive profits to upset anybody. I would love whoever devised this market system to explain why they think it is right the customer should pay inflated prices and thus pay excessive profits to the cheaper suppliers. We keep being told the more renewable generation we have, the cheaper our bills will get. Under the present system that is a LIE. Prices won't get cheaper until there is enough renewable to power the lot and we don't need the gas generators to bid for any.

This was a relevant recent thread worth a look. For the roof they have insulated with wood fibre between the rafters The interesting bit is they have done half the roof with a ventilation gap and half without to see if it is necessary with this type of roof

And attached. and in a mild climate. Your challenge: Achieve that low usage in a detached house in the Highlands, where tomorrow it is forecast to just creep above 0 for the first time in 2 weeks and has been down to -12 in that time. I often speculate just how low my heating bill would be if i had built an identical house in your climate. I am using 1400kWh per year here for heating but because none of that is off peak, all standard rate that's just over £300 per year for heating.