Jeremy Harris

Pity this wasn't out 7 or 8 years ago, might have saved me a fair bit of hunting around for relevant information.

Isn't that box a damned great thermal bridge through an insulated wall?

AS @ProDave flow switch is one cause, as can be a diverter valve fault. We had a diverter valve fail on our old Vaillant, when it was around 7 or 8 years old.

OK until you go to hang something on a wall and drive a fastener through a pipe...

As well as tiling the lot before fitting the units, I also stuck 50mm x 50mm white PVC angle in place of skirting behind all the units. This angle is bonded to the floor and wall with sealant, so if there should be a leak anywhere then it shouldn't be able to get to the bottom of the plasterboard. This also made things easier to clean up when I was fitting things, as it sealed up the small gap between the floor tiles and the wall.

The design does include a shut off outside the property, although not one that can be easily accessed, as they seem to rely on the one built-in to the Talbot fitting on the main, which is now buried and far from easy to access I suspect. Seems bonkers for them not to have fitted a toby somewhere near your boundary to shut off the incoming supply.

There's a shut off valve under the red cap. You need a key to shut it off by the look of things:

Another option might be to just see if you can buy a suitable moulding plane and DIY it. Moulding planes come up on eBay a fair bit: https://www.ebay.co.uk/b/Wooden-Moulding-Planes/13874/bn_7023489768

I'd guess that it should be possible to build a solid garage floor that's a fair bit lower than the house floor, then cover that with an insulated floor to bring it up level with the other habitable areas when it's part of the utility room. If there's a need to convert that space back to a garage, then remove the raised flooring along with the partition wall.

I looked long and hard for a few years before starting our build, and was initially keen on both PV-T and the Magic Box thing. I went so far as to see an installation of "thermodynamic panels" at a supplier in Southampton. The bottom line with the "thermodynamic panels" system is that it is just an air source heat pump that operates without the benefit of a fan to move air past the heat exchanger. The system isn't in any way solar, and in reality the panels seem to work best when mounted vertically. The real problem I found was that neither I, not the supplier I went to see, could get any verified performance data from the Spanish/Portuguese manufacturer at all. In the end that supplier pulled out of dealing with the company. I found a few Irish customers who seemed happy with the performance of their "thermodynamic panel" systems, but none could provide any meaningful data on performance. The inability to provide independently tested data was the killer for me, together with them having been struck off the MCS register a few years ago for falsely representing how the product worked. We fitted a conventional ASHP, and are very pleased with the performance indeed, at the low flow temperature needed to run UFH in a passive house the COP is significantly higher than quoted in the specification. PV-T doesn't stand up to logical analysis at all. In hot weather, when the benefit of taking heat out of the PV panels might be seen as an advantage, there will be nowhere to move the heat. By mid-morning the hot water system will be hot and the panels will then run just as hot as they would without the thermal bit on the back. The only possible advantage of such a system would be if there was some external heat dump capable of accepting a few tens of kWh of heat per day from the thermal bit, to allow the panels to run at a lower temperature. Frankly it seems to be a solution looking for a problem, as in reality an ordinary PV system works fine in hot weather, our 6.25 kWp system regularly maxes out in summer, and all we're doing is stuffing loads of power to the grid at a time when the grid doesn't really need it. We use our PV system to heat our hot water, and that will generally have the hot water system up to temperature and fully charged by mid-morning in summer, just with a 3 kW heating element driven from excess PV generation. With just the two of us, we need about 6 kWh worth of hot water per day, so a couple of hours with the PV system delivering at around half power is enough. My advice would be to keep things simple, and just use an ASHP running UFH for heating and cooling, and use excess PV generation for hot water, perhaps with the ASHP for preheating.

Welcome. There are several here with passive houses, and at least one has found that heating with MVHR works OK , @PeterStarck. We have a Genvex MVHR that can heat or cool, but we've chosen to not use it for heating, as we prefer the feel of UFH embedded in the concrete passive slab foundation. I did try using the Genvex for heating, and it works well, in terms of providing enough heat, but we did find the air to be a bit dry, something that seemed to give me a bit of a stuffy nose. We now use the UFH for both heating and cooling, from a small ASHP, and only use the Genvex MVHR in cooling mode. It's OK for cooling, but not that powerful. The unit we have is the GE Premium 1L, which has a heating/cooling capacity of around 1.5 kW. The reality is that solar gain, even though mitigated as best we could, with solar reflective film on the outside of the glazing and deep roof overhangs, can significantly exceed the cooling capacity of the MVHR, plus, in order to deliver the rated power the MVHR has to be in boost mode, just to shift enough air around. We ended up installing an air-to-air heat pump upstairs to provide additional cooling. We have no heating upstairs, and the roof construction is reasonably well insulated (just under 0.1 W/m².K), with a long decrement delay, yet enough heat was rising up from below in hot weather to make the bedrooms a bit too warm. Heating is really a non-issue we've found, cooling is far and away the area that's caused most concern, and led to changes to the house after construction. Our house needs at most about 1.6 kW of heating when it's -10°C outside to maintain it at 21°C, but probably needs two or three times that level of cooling in spring and autumn, when the low angle of the sun allows it to penetrate more deeply into the house. The best solution would have been to fit external shutters, as these work well, but the planners (or rather the Conservation Officer) weren't keen on us having them. If we'd had the budget, I'd also have looked at fitting Sage glass, as that seems to work very well to reduce solar gain.

Good job I'm no longer a Parish Councillor then... FWIW, my reasons for resigning as a councillor were because I got fed up with the PC repeatedly ignoring everything from laws to policies.

One potential snag with raising the level may be the maximum allowable gradient at the initial part of the access road. We were initially given a standard condition that the initial gradient of our drive at the approach to the lane would not exceed 1:15 for the first 4.5m back from the lane. We couldn't achieve this, due to a conflict with the minimum level AOD of the garage and parking area, but our planning officer just allowed the steeper gradient, on the basis that conditions from the EA apparently trump those from highways. Whether this was just his opinion, or whether it's embedded in policy somewhere, I've no idea, I was just grateful to see common sense being used.

You can sometimes get lucky with the highways people. Our plot originally had an entrance on to a very narrow section of single track lane, in a location that made getting the house, drive etc on to the plot challenging. A local parish councillor mentioned that he knew the highways chap fairly well, and suggested I call him to see what he could suggest. The highways chap turned out to be really helpful, agreed to meet me on site when he was next in the village looking at something related to speed limits, and spent about ten minutes or so looking at options and making suggestions. At the end of this short meeting he gave me his email address and told me to email him when we put the application in, with a reminder of what we'd discussed. The result was, that despite the relatively poor visibility, he raised no objections. Doesn't make getting out of our drive any easier, but as cars can't really do more than a few miles an hour along the lane it's not really an issue. The slow speed of traffic along the lane was the thing that I think swung it for us, together with the chap being just one of those "can do" helpful characters that wanted to help us find a solution.

We opted for a half-way house, decent MDF carcases with solid oak doors. We had the same units for ~10 years in our old house and they stood up well. Not that expensive, either. Worth getting decent hinges, though, as a bathroom environment can be tough on cheaper "kitchen quality" hinges. At our old house I found the plain steel springs inside the hinges corroded fairly quickly. The units we have in the house have Blum hinges that seem to use plated springs, so they are probably less susceptible to getting a bit of condensation. The MVHR probably helps, too, as the bathrooms dry out very quickly here.

Yes, pretty sure that's just what I did. They shipped the printer from their EU warehouse, arrived within 4 or 5 days, I think.

PM is far and away the best way. The forum email stuff seems not to be that great, for reasons we're still working on. Easy enough to set you up with blogging rights if you wish.

I'm wondering if they understood that what was being proposed was a dry riser. These are common in buildings where a fire appliance can't get it's hoses to all areas where there may be a fire, usually taller buildings, where running hoses up fire escapes would present a hazard. Perhaps worth finding out the standard for a dry riser, seeing how much it would cost to install one and then asking the fire officer again, but making it clear that what you are proposing is a standard dry riser. A dry riser will have standard fittings on both ends, usually capped off with hand-removable blanking plugs. These fittings accept a standard fire hose, so the pump appliance can connect to the accessible end and a fire hose manifold can connect to the house end, to allow the connection of standard fire hoses.

You can have a single enclosure, with separation between the LV/SELV sides, or two enclosures, it's really up to you. @jack has a neat set up using Loxone in an enclosure that has separation, looked very neat when I last saw it, and he may have a photo of it. IIRC, his enclosure is split with the LV stuff one side and all the HA stuff the other side. All that's needed for a safe termination is something like a DIN rail terminal block. You can then connect to that as needed within the enclosure.

Indeed it does. The difference for us between the two is about 22m², which makes a significant difference in PHPP.

The normal metric is the net internal floor area, so the area of all habitable floors inside the building shell.

I've just checked and I can't see any restrictions on your account. I'd do as @ProDave suggests initially. If that doesn't work, then it might be worth signing out (using the option in the menu that drops down under your username, at the top right) and then logging back in again, to see if that clears it.

Part P covers the whole LV electrical installation for a new installation, so as long as all the LV feeds are terminated, inspected and tested as part of the installation, what you choose to do at the ends of them is up to you. For example, I ran underground lengths of SWA to various places where I thought I might need things outside in future, and terminated these in boxes. They were part of the installation and inspected, tested and included in the EIC. I could then add equipment to the ends of these cables without the need for any further Part P sign off, as all I'm doing is working on an existing circuit. In the case of the HA stuff, then just get LV cables run to safe terminations where you need things like contactors or whatever controlled by the HA kit, plus LV cables terminated at the SELV equipment power supplies. As long as the LV cable terminations are safe, and can be inspected and tested etc, then you're OK. You can then do all the stuff after those LV terminations in your HA box without the need for further Part P notification, as you're just working on an existing circuit.

Welcome. Have you priced up a GSHP and compared it to an ASHP? When I did the comparison, the GSHP was going to cost between 3 and 4 times more money than an ASHP, and not give any useful running cost saving through life, because the additional maintenance costs outweighed the very tiny saving from the slight improvement in efficiency. We switched away from a GSHP during our build, and fitted a small ASHP, and find it's reaching about the same efficiency level as we were quoted for a very much more expensive GSHP. Ours always runs with a COP of over 3, usually around 3.5, and the running cost is comparable with mains gas (mains gas not an option for us as we're off the gas grid). If you don't have access to mains drainage, then a treatment plant is now pretty much the only option. Easy to install, but they do need a leach field drain, or discharge to a stream or other flowing watercourse (in England and Wales, SEPA have slightly stricter rules in Scotland) or a drainage mound. Best to work out where you can both site the treatment plant and the arrangements for its drainage system early on, as there are building regs requirements around where you can place it, relative to the house, boundaries etc..

Bugger.... Didn't know about them. It's only a small board, though, so wiring them wasn't really a problem. Those dual busbars would have made thing neater, though.