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Thank you! What's the Comms between battery and inverter? I installed cat6 cable alongside my armoured cable, between house and garage, where I want batteries installed . Is there any system which uses cat6 for the Comms?

Looks like I'll be going with something similar. How do you feel about the hose going through the niche, that might drive me wild so might have to offset the niche instead.

Well that all v interesting, thanks. I guess my longest straight runs are about 6m, so maybe 15-20mm expansion at a delta T of say 25C. So, it sounds like expansion is a thing to think about but mostly taken care of by pipe geometry and a little care with installation i.e. allowing it to expand and shrink and generally move about a bit without a problem. Could trip you up though if you were not bearing it in mind.

A follow up on this thread. I bought a fogstar 16kwh DIY kit and Solis 5kw hybrid inverter back in March. Inverter installed and set up fine but the inverter I bought needs a DC supply to operate so without a battery or generating PV it's dead. With a faulty battery that becomes a problem leading me on to..... Fogstar kit went together OK following 3rd party YouTube videos.....the Fogstar documentation isn't the best. I had problems balance charging and after a couple of weeks Fogstar tech agreed I could build and use the battery. Had problems with a couple of cells which Fogstar were reluctant to replace and accounted for the struggle to balance charge them. Not long after I started using the battery there were a couple of instances of the battery collapsing and dropping to 0% charge in front of my eyes. After weeks of back and forth with Fogstar tech and stripping the pack for balance charging a further 2 times, Fogstar took the battery back for 'test and proper set up'. 3 weeks later I got the battery back and 2 days later it collapsed again so went back for a refund. In the months I had the battery Fogstar stopped selling the kits and the cells that go in them so I guess I wasn't the only one with problems. Spoke an installer who sells Fogstar kit on ebay and he convinced me the product is good so I bought a factory assembled battery through him and it's run perfectly for the last 2 months. There's another one on the way to help with the winter load. I'm happy to recommend fogstar kit but just be aware that after sales can be lacking!

I have discovered that SWMBO's shower arrangements are completely different to mine. I very rarely use the side shower and she NEVER uses the overhead. I would suggest (i.e. I have been informed) that the riser bar is a necessity as whatever height you were to choose, either hair or body washing would be sub-optimal and therefore unacceptable I have a Mira digital and it is awesome. This is the arrangement in our downstairs bathroom. You can just see in the bottom right hand corner where the edge of the controls is. I would disagree with ProDave above as there is a delay between pressing the button and the digital shower kicking in, that delay is sufficient to retract an arm without any dampness , also the digital showers retain their heat settings so no twiddling is required Regards Tet

Plus those using something like a heat geek cylinder, could be spending a couple hours heating via the heat pump. I was finding a reported CoP of 3 to 4 over a few years, but reality is I haven't seen a noticeable change in electric consumption or export amounts since moving to immersion only DHW. So really ASHP is not as efficient as it cracked up to be.

Duck.ai:- https://www.legislation.gov.uk/uksi/2010/2214/schedule/2 - See CLASS 6 Point 1.

My point entirely, as above, you need to choose a time based on your own statistical information from your own inverter app either way, but it’s just a pointless exercise to get your heat pump slaving away when you won’t use all the excess up anyways. Plus if cooling then I’d not want the heat pump being pulled in all different directions. Any homes with fan coils and no buffer would see these shutting down during DHW production too. Juice > immersion = dead simple, and with a decent PV array you’ll still end up exporting anyways so why end up with a tired heat pump at all? ASHP’s take time to get up to temp too, so this situation isn’t as efficient as it first sounds either, whereas the immersion is a whiff under 100% efficiency. So,

I've heard that before, but not been able to find the document. Do you have a link you could share?

Or just time DHW to coincide with peak PV production, heat to normal temperature via immersion thermostat. Leave heat pump to do heating or cooling and immersion to do DHW or if DHW production not needed export, just export or charge battery - maybe both.

It’s not a real world problem, and I have been putting Hep2o into very large projects since 2010, and beyond; never a single groan, creak, or complaint. The only instances of failure I have ever heard of are from JG Speedfit, where idiots have not used the plastic cir-clips and the fittings have simply unscrewed themselves. Not a good design, but most merchants sell bucketloads of the JG fittings each day (but stare blankly at you when you ask for cir-clips). #tickingtimebombsaplenty My comment regarding real world doesn't mean the pipe does not expand, “ye cannae change the laws of physics, Jim”, it means that in real life you won’t have a house that does not require the pipe run to turn left / right and go uppy / downy and more. Ergo, the issue is self-resolving; you will not have any arrow straight, fixed point A to fixed point B runs without a single turn, (in all likelihood / reality, and my continued direct experience(s). Note: I do not directly fix the distribution pipework any more, instead I insulate the pipes with EPS lagging (minimum 9mm wall) and then I band to that relatively loosely; this is so the pipe is free to creep inside the insulation without the ‘grabbing’ that comes from clipping to it directly. Also means 100% of the pipe run is insulated vs stopping and starting at each clip. I consider the ‘here and now’, but also the not getting of “that phone call”, eg the one where I get informed that the pipes are making noises (behind the paint, plaster, plasterboard, insulation etc); by then they all live there too, so adding in the upheaval of having to fix things after the house becomes occupied = feck that! Belt & braces people!!! Furthermore, I almost always fit an accumulator on the cold mains and this will accept any unwanted additional ‘peak’ expansion too, should such a thing ever occur. The UVC control group does not feature an NRV btw, so all of the hot network can ‘see’ straight to the accumulator. Re the 55°, temps are only that high on runs to the kitchen sink / utility sink (55°C is my go to, to cut / emulsify grease etc effectively) with everything else being <50°C; baths MUST be capped at 46°C so you’ll either need these off a TMV, or to have thermostatic bath taps / fillers which can be commissioned to go no higher. I almost always go TMV as it kills more than 2 birds; reasons to follow. As an aside, 46°C bathwater is too bloody hot for me by a mile, as I’m not a fan of steamed plums. Anyhoo….. I am currently in the middle of plumbing a sizeable dwelling that I have “designed” for, with 1x full family bathroom, 1x full master ensuite, 1x teen shower room, 1x guest ensuite shower room, a cloak WC, kitchen, and utility. *Full means bath + shower. All this is being plumbed in 15mm Hep2o with the longest run being about 18/19m, bar the cloak WC which is in 10mm as it’s next door to the wet plant room. That longest run is to the teen shower room which is at the opposite side of the house to the ‘wet plant’ room; originally this teen shower room didn’t feature in the house design, and everything ‘wet’ was on the side of the house that was local to the ‘wet’ plant room. I suggested adding this teen shower room mid-build, to keep the kids ablutions ‘that side of the house’, but also to mitigate excessive wear and tear on the (to be very nicely presented) family or guest bathrooms; reduced cleaning / extended longevity etc etc and reduced noise at the bed 1 side of the landing so mum and dad can have some peace. I’d kill for that tbh, ours is like the O.K. Corale all bloody day and night. All basins, the teen shower, and the kitchen sink will be on the hot return circuit; controls methodology is currently being pondered over, but no 2 projects / client(s) remit are the same so these always differ. For this project the lions share of the hot outlets will be fed via a TMV at 46°C*, usually only 22mm but in this instance I will beef that TMV up to 28mm and take off it both of the bath hots and 4 shower hots, to cap the distribution temps in those pipes and reduce latent losses (albeit these will be quite insignificant in real life as this all happens within the heated envelope) and to stop excessively high water from leaving the UVC to then be lost as wasted energy. In a nutshell, no hot water leaves the UVC without going via thermostatic control. *Not being able to scald yourself anywhere in the home is also something that should be considered; especially with young kids or elderly / infirm etc. Most hotel showers would see me in the burns unit if I flicked the controls the wrong way….. The kitchen and utility sinks are the only exceptions here typically, but that’s on the proviso that I’ll be including another TMV (15mm) to cap that at 55°C. This allows us to max out the stored temps in the UVC when PV is covering hot water production via the immersion on timed bursts; late morning and another early > late afternoon etc (in line with generation info gleaned from the inverter / app to say “when’s best to do so”). Differs job to job obvs, and also very relevant if you're using timed chunks of off peak electricity > immersion; immersion would be set to max out the stored heat energy at say 75°C then, to increase the storage and utilisation of the cheap energy, hence you defo need the 55°C TMV so extremely (eg scalding) hot water can never arrive at ANY outlet, ever. Some will argue that the cheap or free electricity should go into the heat pump and that should provide DHW, but I argue back that you cannot expect a heat pump in summer to be jumping back and forth from cooling to full blast hottest possible temp for DHW for 15/30/60 mins, and then screeching to a halt thereafter to go back to cooling. Yo-yo’ing back and forth like this cannot possibly be good for these things, imho, adding unnecessary wear and tear to the heat pump (when you can just dump this straight into a 99% efficient immersion heater and let the heat pump lay down, or sleep). IMO, if you give your heat pump an easy life it’ll live longer, and given the choice between immersion or heat pump, I know which one I’d rather have to replace. Some digression, but best to give some additional info, as is ‘the way’ here. Bonjour.

Lovely to see how well it's going

For internal floor space up to 30m2, no building control required in England. Don't tell my friends about my uncalibrated tape measure.

Yeh ours is 5m x 5m at present but new house has been drawn 900mm off this. If i put a new roof on upto the house wall will be 6mx5m

Our max temp difference will be 35°C (ambient background temp min to max hot water temp). Long runs are bad news for hot water so to be avoided anyway. (Most of our sinks/basins are served by 10mm hep to get hot water PDQ, which is working well though it does mean the flow rate isn’t torrential). In practice I’ve only one straight section over a metre long and that’s to the garage through a 4.5m duct with bends either end. Do you really need long straight sections?

We bought a house once, the builder obviously didn't like to use a tape measure, as the garage was just over a metre longer than it should have been - it was great. Nice sized garage to build a kit car (Dax Rush)

No insulation means walls become cold with limited air movement, cold walls equals damp walls when you have very limited air movement caused by adding some furniture in close proximity to the wall. Adding some insulation leads to less cold walls, less damp, no mould A bigger air gap allows more ventilation, leading to less issues. Or just insulate the external walls, no mould less need for heating win, win. May not be a small task but as maybe doing loads anyway a good addition.

You don’t. there is absolutely no reason to be heating your water to that temp, so expansion is not a thing to worry about.

Both @G and J & @LSB called in recently. Nice to see them. Feel free if you’re near Sax. Preferably near the end of the working day - 3:30pm according to my carpenters

Cooled UFH with ASHP works v well according to some friends who just discovered their HP has that function. We’ve put in some 180mm back-up ducts for central AC, but expect not to have to use them.

Heat pump cylinder is more expensive, vented or unvented is a design choice doesn't matter how it's heated. Unvented runs the cylinder at approx 3 bar, vented has a tank in the loft to supply the pressure. Depends on size of immersion and size of heat pump and how it's set up. It doesn't, but with a heat pump you are EITHER heating house or cylinder, not both. So if cylinder takes a hour to heat in a 3 hour cheap period you only have 2 hours to heat house.

None, mine came with the install that's all.

Hi Susie, I’ve just come across your R-wall build blog and it’s very informative. Me and my wife are in the process of building an R-wall 1-1/2 storey house just outside North Tamerton and we’re close to the plasterboard/plastering stage and are debating whether we get plasterer’s in or do it ourselves with tapered edge joints like you have. Dave.

Are normal cylinders a lot cheaper than heat pump ones? Are they "vented" or "unvented" or doesn't this change with direct heating? Can an immersion heater recharge the water temperature as quick as a heat pump? Why would heat pump cylinder stop you heating it in cheap period?

Do you have to have regs or a warrant for that? What's the total size 6m wide by how long? What size timbers did you use? Im thinking of extending a garage from 5m wide to 6m and it's a bit of a can of worms. Think I might need to involve an SE. while it will only be 30m2 or just under I think if it joins a house it has to have b.regs in England?