jack

That's true. Still, in a town centre, you'd probably need to use vertical boreholes, which add significantly to the cost.

Interesting looking build, hopefully you can share more details in due course. I think we've probably reached the point where GSHP is simply not a cost-effective option compared to ASHP. There might be the odd special case where you have a large field next door that you were going to massively dig up anyway, in which case GSHP might approach price competitiveness. But in general, GSHP setups are at least double to price of an ASHP of the same output. If properly done (and that isn't always the case), the GSHP will have slightly higher efficiency, but not enough to ever pay back the price difference.

Awesome news. Despite not having a programming background, I found the programming side very satisfying.

I think we ought to be encouraging larger tanks. They store the same amount of energy at a lower temperature (suits ASHPs) in the colder months, and allow greater usage of diverted PV power when the sun is shining.

Welcome @Allyzap The forum search is a good start, or you can Google "subsidence site:buildhub.org.uk" for slightly better results. If you want to post something, the "Foundations" sub-forum is probably a good place to start: https://forum.buildhub.org.uk/forum/73-foundations

Very useful, thanks for reporting back @Ultima357

Man, I feel for you. We had an UFH pipe nicked (honest mistake) in a much more accessible place and even that caused a lot angst.

Worse, a wooden floor is going over the top.

My recollection is that the consultation date is the latest date by which you can submit comments and guarantee that they will be heard, but there's nothing to stop comments being considered after that date. I think you or a trusted friend being there to take notes would be highly desirable.

I've heard from more than one source that testing them (or having them open due to an over-pressure/temperature event) is the quickest way to cause them to fail.

I've had this problem repeatedly over the last 8 years. First time I noticed it, it was exactly as Dave said (expansion vessel bladder failed). Replaced the expansion vessel, but it still leaked when the immersion diverter was on for any length of time (albeit not as badly). Had a G3 service, and one of the temp/pressure safety valves was found to be leaking. That was replaced, but I still have the issue, and I notice it's gotten worse again recently. No help to you of course, but in answer to your question, yes, they can fail!

Thanks for the photos. Is your stone base MOT1 or similar? I've more commonly seen large no-fines stone specced - something like railway ballast.

Fair enough. I rarely change titles, but someone searching for information about inverters ought to be able to find this thread!

I'd at least run the cabling for three phase. It's orders of magnitude more work to go back and add it later.

Welcome!

It might depend on what "making people abundantly aware" involved, but I think it could well be their fault: That said, if I learned anything during our build, it's that virtually no-one ever listened to anything we said. In my experience, unless you were stood there looking over their shoulders, most trades just did things however they fancied, irrespective of what was agreed beforehand.

Unfortunately it won't be that easy:

I didn't say above, but I have a 250 L tank and I think it's too small. If all four of us have a shower in the morning or evening, there's a chance we might run out of water (especially if number two child isn't physically dragged out of the shower in time). We also have waste water heat recovery, which probably helps a bit, so if you don't have that it could be even worse. Also, we have a PV immersion diverter. The larger your tank, the more free heat you can store. On sunny days in summer and some of the shoulder months, with a big tank you can probably store a couple of days' of heat from just one sunny day. I'd probably be looking at 400 L if I were doing this again.

If I were doing it again, I'd consider a larger DHW tank and a decent sized buffer for the UFH to allow more heat to be stored during the cheap overnight period. That would also enable a larger ASHP to be used, as it wouldn't need to modulate down so much.

If you're using an ASHP, I'd go larger than the recommendations suggest. A larger volume allows you to heat more water to a lower temperature, giving you the same useful output but allowing a higher COP.

Speculating, but: As a gas, water is just a bunch of free H2O molecules flying around. If they find a hole big enough, they'll work their way through. In contrast, the molecules in liquid water are attracted to each other due to their polar nature. The negative side of each molecule is attracted to the positive side of adjacent molcules. Surface tension is an example of this - the attraction causes water to form droplets rather than spread out in a molecule-thin sheet over a surface. That attraction causes liquid water to clump together in a way that impedes its ability to traverse pores that are big enough to allow individual water molecules to pass through.

All of the temperature sensors were already installed, and I had spare relays, so there was literally zero hardware cost to implement it in Loxone. Feel free to query the need for home automation, but why would I add the cost of a separate thermostat that's guaranteed to be at most (but almost certainly not) as functional?

I use it in place of a thermostat. It allows me to do things like enabling limited overheating during the cheap Octopus window, forcing heating when upstairs gets too cold. It does add complication, and arguably we could just accept the limitations of a fixed thermostat, but it seems a shame to have the capability and not use it.

There are quite a few of us. Use the search function to find out more if of interest.

Discussed here. Locking this thread so we keep everything in one place.