joth

Yes definitely worth it if you're planning running Frigate, saves masses of watts to offload image detection from the main CPU Thankfully USB version available again now. I got mine during the post pandemic chip shortages , and the PCIe format limits how and where I can run it.

Tighten the cams in the windows until they were virtually unusable (pushes the sashes firmly onto the baffle). Use the shittiest fitting door as the one you replace with the air-tightness fan. (in the end we used the best-fitting window). Ensure all shower traps etc are filled, or tape them over. (Fair enough. Except we later found one shallow trap actually wasn't full but nvmd got 0.5 anyway) But I think the most negotiable one is to be 'generous' with the calculation on treated floor area and volume of the building, especially relating to noncuboidal shapes (vaulted ceilings etc)

(I haven't read every comment as they got a bit duplicative, but I have some points didn't see mentioned) Our main bedroom overheats badly, even in winter. (Passiv retrofit, 25khw/m2/year heat requirement). Unaddressed it easily hits 25 deg C. We'd be happy to have 20deg same as the rest of the house really. We don't open the window as trainline right outside it. (Indeed, we partly went for a passivhaus with triple glazing and thick walls on basis of the sound reductions). We don't open the door as don't like the cats strolling over my nose. It has an MVHR supply vent (and extract in the ensuite) but this makes very little difference, on boost+bypass vs off altogether. after a 2 years I have it a very pleasant stable temp. measures taken: - automatic shading - ducted fan coil in the loft supplies active cooling in the summer (ASHP set to cooling mode, running in Octopus Go cheap rate) - the same fan coil air inlet is fed from an electric duct damper that redirects air to draw from a spare room in winter. By happenstance that room is always 2-4 deg cooler than the rest of the house, so cycling this air through supplies most of the cooling needed - bonus: when the ASHP is in freeze protect mode, it circulates the water to keep the outside pipes warm which also brings an amount of cool water into the circuit, which is also routed through the FCU for a bit more cooling power. (Providing free freeze-protect for the ASHP or free cooling for the bedroom, depending which way you look at it) If doing it again, I'd consider - higher / vaulted ceilings in the main bedroom, to reduce the time it takes the room to heat up. - providing dedicated circulation duct between the bedroom and hallway (which has a stack venting skylight) - provide a more enclosed cat area downstairs, keep them out of upstairs overnight - live somewhere quieter; have an automatic skylight or other stack vent option in the bedroom

Only if you don't also use smaller per-circuit RCBOs in the panel. Ack, I see your point. Every sparky I worked with so far wasn't keen on having double earth-leak protection on any circuit (even with different sizing) but I admit that may also be my own preference/bias I'm projecting onto them. When I did multiple circuits + RCBOs in the CU I also put some per-circuit MCBs in the Loxone panel for convenience (the sparky didn't even want them there, but accepted that I needed them for my own peace of mind, especially as the RCBOs were scattered over 2 CUs)

Downside of this is an earth leak (especially likely on an outdoor circuit, but easy when changing a lightbulb indoors too) will trip all lights in the house. Sparky on my current project wants 2 RCBOs per floor to ensure everywhere still has some lighting even in the case of nuisance trips. I think we're up to 12 RCBOs in the Loxone cab, and about 30 more in the main 3ph DB

So each sparky has a different take on this, but the common view is the place that contains the isolation and earth leak protection is the thing that has to confirm to 18th edition IET cu rules. By putting all isolation and rcd in the main CU you may relieve the Loxone cabinet from having to comply as a CU, effectively it's just another custom-built appliance. (Or, collection of CE marked appliances assembled in one box for convenience). Note the CU regs are more than just the enclosure having the 18th ed mark, it also includes correctly sealing all openings with grommets and so on. Of course it's a good idea to try and comply with as much as you can of that anyway, regardless of technically whether or not it "is" a CU. The point here more is about the scope and ownership of paperwork involved for signing it off. I've built cabinets both ways. In each case led by site sparky preference and also by having site sparky terminate the cables into the Loxone cabinet it's their ballcourt to seal openings into it as required and sign it off too

I found a surprisingly accessible illustration of the effects of wave reflections and wire branches in this video. Despite having a masters in the subject I'd never really considered the interaction of potential voltage and current in this dynamic sort of way.

All very familiar sounding. Our principal contractor sent their air test guy, he was telling me all the "tricks" to improve the result. He just couldn't understand when I said no, I wanted the genuine result not a contrived one, even when I pointed out as the occupier, not a property developer looking to flip it. This is why I was interested if the remedial works consultant, working on behalf of the owner, did a honest air test.for them

Yeah I get a lot of developer builds aren't tested, I was asking specifically on the second set of thermal camera images which were done during an air test being conducted by the independent consultant. Did they actually measure 3.5 in that post-completion test?

As shocking is it is depressingly unsurprisingly. Do they mention what the airtightness test result was?

Yes they can, mine has volt free contacts that allow two settable flow temperatures for heating and two for cooling. You can only do one temperature at a time. So could us a diverter valve with microswitch to control it and simple time switch. The ecodan is slightly smarter in that if you only have one zone on it will operate at that flow temperature, but if both are on it will pump heat to the hotter one (or colder one in cooling mode) and use the electronic blending valve to maintain the milder temperature on the other zone However, it is also dumber as it only has the two dry contact inputs (Z1 and Z2 resp.) and switching them between heating and cooling mode is manual setting change, or if you're feeling lucky via a seasonal schedule in the cloud portal.

More water in the system means a bit more glycol needed, if using it. And maybe slightly longer response times (more water to heat, but offset by less screed) Both pretty negligible in grand scheme

It's hard to call it an equivalent as frigate is far more limited functionality, but for me that's a real plus as frigate does everything I need in an easy to manage package, with massively less grunty CPU and power consumption. Get an edgetpu for it though if you possibly can. Keep blueiris about for doing device discovery on new cameras, it's the best I found for that. Articles rave that frigate must be run "bare metal" but IME inside docker is just fine. I do have the edge tpu though.

Aye - I got a "great price" on my install and one gets one pays for... there's so much of the system I had to debug/fix/update it's a bit mad. Anyway found a V4044C1288 for 72gbp on fleabay so I'm getting that now. The mid-pos valve has "worked" for 2 years (used just in the end stop positions) but I really don't trust it.

Backstory: this summer I changed my system from glycol to anti-freeze valves, and enabled freeze protect on the controller. Now, when freeze protect is running I notice my UVC appears to cool more rapidly, and need more reheats per day. I've long noticed it occasionally runs down temp super quick at other random times too, even with no DHW draw off. The secondary return pump is on a timer and motion sensors, and does not impact this even if disabled. My hunch is that the mid-position valve sometimes lets water by into the DHW coil, even though I've confirmed electrically that it's in the heating-only position. (Neither grey nor white wire energized; it's installed "backwards" so spring return post B is for heating only, and port A is for hot water open when grey+white energized. We never use the mid-position state for obvious reasons. It being backwards makes sense in my mind, as the system is used in heating much more than DHW mode, esp with freeze protect, so this avoid the valve being energized for the majority of the time). I've confirmed the ASHP controller freeze protect intends to only circulate heating, not DHW. (And this is great as theoretically the cold water from the external pipework will then flow to our bedroom FCU and provide "free" room cooling when it overheats at night: effectively using our excess body heat to stop the external pipes freezing! lol) I know @ProDave has a hatred for this mid-position valves, and I agree, I wish I'd put my foot down about my installer using one in the first place, damnit. Anyway questions: 1/ is it likely it's letting water by to port A when in the spring return closed position? It's only 2 years old and the system water is clean, I can't see it is sticking but wdik. 2/ is there an easy way to test if it is letting by? 3/ can I just swap out the head from mid-position to diverter (i.e. from V4073A to V4044 series), or does the whole valve body need changing too, entailing another system drain down? 4/ is it worth doing this anyway, for piece of mind? 5/ any recommendation for a more reliable make of diverter valve that's a pipe-compatible drop in for the honeywell V4073A range? (the primary circulation is in 22mm pipework) cheers

I recently turned off WC on my ecodan, just during the Octopus Go cheap rate window. Full explanation in the thread linked below. This is extremely effective in reducing costs (or actually, attaining a more comfortable temperature during cheap rate only) during colder days.

Great list. For me "Installed in accordance with manufacturers' recommendations" is a key one. I had to put so much right on mine just to make it match the MIs. And of course meeting building code and the MCS guidelines should get a mention here too. "Set up correctly to achieve best attainable performance" I think is perhaps asking a bit much. Best practicably attainable maybe more like it. It's uneconomic and unrealistic for an installer to chase diminishing returns by squeezing out every last possible saving. That's like expecting a service in the local garage to race-ready tune your car. What's important is to avoid egregious design or commissioning errors. It's far too typical for installs to have short cycling, setup with very high flow temps, no weather compensation, or oversized buffers, any of which can kill performance and the COP>3 goal. (Many these do however avoid maintenance call outs, which lets be honest is why it happens)

Sort of. You only need an "adequate" installation to achieve COP of 3, I'd say the nuance here is that the typical UK installation in below adequate.

That's talking about the fixings to install the propassiv itself, not for subsequent bulky items attached to and hanging off the propassiv. In most cases these will involve drilling through the propassiv to fix into a rawlplug in the wall behind it. That's where taping and/or sealing the drilled hole really comes into its own In a few places in the loft I used self drilling masonry screws to attach items on top of the OSB and these worked well. (although in many cases they ended.up being removed and reinstalled so I taped over the holes then, not actually aware this was the recommended practice)

Just to clarify, this approach only works where you have direct access to the OSB or whatever behind the service void, or to a layer that is fixed directly onto the airtight layer without any service void. In places with plasterboard over service void, you can't through screw the plasterboard, void and into the solid OSB/wall behind it. As well as making it hard (neigh on impossible to seal the hole in the airtight layer as you say, it also doesn't make a good finished: the item being fixed will squash the plasterboard and bow or even crack it in two if tightening the fixing across a void into a much stronger anchor behind the void. Using a plywood pad directly behind the plasterboard (so fully supporting it from being bent) is the best answer there as mentioned. Or, look at Habito or Fermacell instead of plasterboard

Yes forgot to add, we did this (on internal stud walls and external service voids) wherever we foresaw hanging stuff. Still, loads of places we didn't do it, and retrospectively wished we had.

it's a good question. We did 25mm service void with traditional battening and gypsum pasterboard, and I've made a dogs dinner of installing various things on it. Especially in the plant room, which I've now found is much better done with Ply or MDF, and perhaps no service void but surface mount pipe/trunking for electrics etc (general feeling in my build team was drilling through the airtight layer is OK for fixings if necessary, so long as squirt the hole full of some glue or sealant prior to putting the screw in. We achieved 0.5ACH on a retrofit so seems legit) For the service void approach, some people recommend Habito or Fermacell for much more robust internal walls, various threads on them here e.g.

I've got one of these cheap R290 units in the gym shed, and the wifi app is quite usable for monitoring temperature and adjusting settings remotes. Despite going through Chinese servers (actually central europen data center, but Tuya is the chinese company in control of it) it's far easier to use and more responsive than the Mitsubishi MELcloud app on our A2W hp in the house https://www.appliancesdirect.co.uk/p/eiq-12wminv/electriq-eiq12wminv-wall-split-air-conditioner Not specifically pushing that model, just saying if fairly entry level units have reasonable app support then I'm sure more luxury brands would (although honestly think their proprietary apps could be worse, given the Mitsu experience). Doing a multisplit unit might complicate built in wifi controls a bit, I don't know As a bonus I linked mine to Home Assistant so have made automations to act as frost protection, auto power off after a period of inactivity in the shed, etc. but it's fine to use without that. (The Tuya Smart Life app has some basic routines support built in, and you can link to Google/alexa routines too if wanted)

You need a room by room heat loss calculation for the proposed build. Various ones exist online, a lot of folks here report good results using the spreadsheet from here:

Yaaah It's always a risk with online forums: people love to answer a question in their head, rather than the one you ask. (I don't see "should I switch to ASHP" or "will it payback" anywhere in the OP, yet that's the Qs many love to jump on). Although to be fair, the first few responders where on point. To the question you ask, yes, if you're daily demand is 5kWh then a 6kW ASHP can achieve that in one hour, let alone 6 your have available. Caveat: it depends not just on the ASHP size, but the emitter size and their ability to put out that many kW at a lower temperature. Getting an Mitsu ecodan to efficiently and effectively use Octopus cheap rate in this way takes a bit of effort. See recent discussion in this thread, for example