Dreadnaught

Thread is one of the technologies (along with Wifi, and Bluetooth but only for initial connection) that will be used in the forthcoming Matter standard that is being sponsored by all the large manufacturers, including Apple, and which officially launches next year. I shall be centering my home automtation system on Matter (and thus Thread too). https://buildwithmatter.com (The alliance behind thread grew from the Zigbee alliance, which renamed itself the connectivity standards alliance).

Yes that is what I guessed. As a fan of simplicity, I hoped that abandoning zones would make the plumbing simpler. It seems it might. Although there seems to be a consensus that no zones might be going too far. By the way, what is Ambisense? Are they just smart radiator valves? Do you use them with radiators or with UFH?

Good point. Another similar eventuality is solar gain from the sun, especially in the late afternoon. Presumably that cannot be predicted by weather compensation, which I guess relies on temperature forecasting. Going back to @Nickfromwales point about the heating system having a long time constant (because of the mass of the concrete slab), my response to your point is that there is nothing much you can do about the overheating, even with zones, as any intervention will only have a appreciable affect some hours later. I can imagine that the only remedy is to anticipate that forthcoming big-party-of 20-people in the morning before and just turn the whole heating system off in advance. Equally, might the ASHP controller flip the system in to reverse cooling mode when it detects overheating. I don't know. Regarding solar gain, it was (long missed) @Jeremy Harris who highlighted the benefit of running the circulating water through the UFH pipes without a heat source, to redistribute the heat around the house. Thoughts?

Thanks for sharing your insight @ProDave. But in your case but without multiple heating zones, without multiple thermostats, and without automatic valves on your UFH manifold linked to a wiring centre, wouldn't you instead manually dial back the flow rate on those loops that supply the zones that heat-up the quickest. Once manually balanced like that, all your zones would reach the target temperature at approximately the same time. No over heating. Simpler system. A one-off exercise to set it up. In practice would that work? Am I misguided?

Thanks @J1mbo. Your experience of living with the system is very helpful and encouraging. That's interesting. In my case, that the coldest room in the house will be the Utility Room. We have laid the UFH so that the supply runs that traverse under the Utility Room are insulated. The Utility Room will only receive heating from the (depleted) UFH pipes that return from the large main Living / Dining / Kitchen area. Mine will be a pretty well-insulated and airtight house with MVHR so I expect that all rooms within the thermal envelope will be similar in temperature. Would the Utility Room be a good location for the Vaillant controller? It was actually where I was planning to put it anyway, to hide all such gubbins.

I'm even hopeful that the above approach might simplify the plumbing by removing the need for the usual hydraulic decoupling between the ASHP and the UFH manifold with a low-loss header or similar. I assume some form or expansion vessel would be needed. But perhaps that is all. I would certainly aim to need neither a wiring centre nor wiring for multiple thermostats. (As you can tell, my plumbing knowledge is near nil.) For DHW* I am still toying between a Sunamp** heated by off-peak electricity and thus completely separate from space-heating. Or having a more conventional unvented cylinder matched to the ASHP, such as Vaillant's own UniTower all-in-one, and therefore linked in with space-heating too. If I chose the Sunamp route, I am slightly concerned that the ASHP would stand idle for about half the year, when neither space heating nor cooling is needed. My fear is that idle appliances aren't happy appliances. * DHW: domestic hot water. ** probably a Sunamp eHW 9.

Thanks @ProDave. My own instincts on this broad subject, and based on my reading around the subject, is to have a relatively small ASHP. Set it to run at a low temperature and almost constantly. And allow it to adjust the temperature using its own controller, which I can tweak the curves for a while as @J1mbo said, but with the aim that eventually it will be "set-and-forget". Oh, and not to bother with any heating zones or indeed any automatic actuators on the manifold at all. The relative room temperatures can be tweaked as needed by manually turning the manifold knobs on a set-and-forget basis. And have but a single thermostat in the living room (the one in the image above). Oh, I also plan to have electric UFH mats in the bathrooms so the floor feels toasty-on-ones'-tootsies in the winter. And this can operate as auxiliary heating if needed in the coldest depths of winter. If even that proves insufficient, a dimplex or two should suffice in a severe cold snap. (And use the ASHP to cool the house in the heights of summer too.) Keep it really simple and aim for set-and-forget. Am I nuts?

Yes, I would be happy to tinker over weeks or months. What is the alternative? I wonder how else one could attempt to put the right amount of energy in to the house over a 24h period to maintain the temperature at an approximately constant level while the weather varies? I think @TerryE has a custom computer algorithm to do it linked to a weather forecast. But that's the only alternative I can recall.

I don't have any details about the weather compensation, other than: "sensoCOMFORT comes with an outdoor sensor which provides an understanding of the thermal behaviour in and around the property and adjusts the flow temperatures to ensure optimal efficiency". Oh, and it has a pretty LCD screen so it so it must be good.

Good point. Perhaps it will be as effective as having separate heating zones within the house. But as a standard feature of the "SensoCOMFORT" ASHP controller (don't you love those marketing names), I suppose it can't do any harm.

Next I will be putting on the external cladding of my timber frame (Cedral Lap planks). Beforehand I am looking at all the penetrations through the exterior wall. One penetration is the wire for the ASHP controller's weather-compensation sensor (see image below of the sensor). The manual says "Connection wire is 2 x 0.75 mm²".Google says this is "2192Y" wire, which seems to be a common type cheaply available from Screwfix, etc. Should I … just buy a roll of that wire? install it through the wall with a loop outside and a longer loop inside? Should I use a cover plate (see below in orange)? Or instead just slope the penetration downwards and back fill with silicon? This is my first bit of "wiring" so would appreciate any advice and suggestions.

Ah thanks @shuff27, that's helpful to know.

By the way, I intend to put a in-line pre-filter box on the intake like this. This will be a coarse filter so as not to add too much resistance to the air flow. And which will catch errant flies and so on. WIth the new duct runs, this could now be in the neighbouring Utility Room: more easily accessible for filter changes. I am a bit cornered about condensation forming, on the inside in summer and outside in winter. I may look to have a tray underneath to catch any condensation.

I have a question about how high to drill the the holes. Back on site, I had another careful look at the position of the holes. I realised that I cannot drill through the span of a posi-joist as I planned. This because I would be cutting through the top of the wall cassette, so hitting the horizontal I-beam that is its cap. This means that I will instead lower the holes beneath the ceiling of the plant room, which will make the drilling easier anyhow. (This in turn means that, to achieve my desired separation between intake and exhaust (of 1.5 m) that I will run the intake duct through the stud wall in to the neighbouring Utility Room.) My new question: I have high ceilings, 2.8 m. Now that the holes are below the ceiling, how low can they go? Could be at 2 m height? Could they be even lower? Or is higher better?

The pozijoist is touching the wall. Ingenious! Thank you to everyone once again for more ideas. I'm back on site on Saturday and I will be up on my step ladder again for another look… and think.

I checked them with a tape measure so all looks well. Good point. It is foam mass-flow ductwork so I think it should be OK. It should absorb any vibration. And, too, the joist in question only serves a utility room and the main bathroom, fortunately not a bedroom.

Good suggestions. Thanks all! One problem. For the inside holes I will be cutting through the span of a posi-joist, which is positioned against the wall. I don't think there will be enough space for a jigsaw. The posi-joist is 304mmm, so a 200mm howl will only just fit, as follows:

How do I go about drilling holes in my exterior walls for MVHR ducts (2x) to atmosphere? What tools should I use? How should I do it? Guidance, suggestions & tips most welcome! External walls (closed cassettes) OSB, 12.5mm, Smartply Propassiv – inside Empty cavity 240mm, to be later filled with blown-cellulose insulation. Studs every 600mm. Magply, 9mm – outside House warp: Tyvek Firecurb Ducts (2x) Ubbink 160mm (internal diameter) insulated ductwork External diameter: 192mm External cladding (not yet installed): Cedral lap planks (190mm, 30mm overlap), over treated battens. External wall terminals (x2):

Oh, and I positioned the MVHR unit as far away from the bedrooms as I could, even taking the precaution of placing it on the far wall of the plant room. In a well-insulated house, which is airtight and triple-glazed, and which therefore tend to be whisper quiet inside, even small sounds become noticeable, sounds that would normally blend into the background of a normal house.

The two main sources of noise are (i) the unit itself and (ii) the high speed air in the ducts. And for (ii) especially the turbulence caused when the velocity of that air changes at, for example, the point where a duct joins a larger valve, such as at the point where air is supplied in to a room. (i) is addressed by buying a better quality Passive-House certified unit and fitting silencers. (ii) is addressed by slowing the speed of air flow in the ducts by increasing their cross-sectional area by doubling them up. The rule-of-thumb for noise in ducts is to keep the speed of the air below 2.5 metres per second on boost level. I went even lower.

That's me! You embarked on your path 7-years ago; I am taking my first steps on mine. (I am presently ruminating on the daunting prospect of installing 4,820 brick slips during the winter.) You were once the pupil; now you are the master.

I have just specified and bought my MVHR kit. But I have not installed it yet. I purchased it directly from the manufacturer of the unit I chose. Great service from them, by the way, even including a site visit, when he was in the area visiting someone else (!) Like you I was keen on whisper quiet. First, I chose a PH-certified MVHR unit and bought the ducting from he same manufacturer. Choosing a quite unit I think is key to having a quiet system. And I slightly over-specified the unit too. There was a smaller model available that would have been sufficient but the price difference was small. To tackle the risk of noise, it wasn't required by the MVHR designer who did the calcs for me, but I chose to pay a little extra and double-up almost all the duct runs (other than very very short ones). I also chose to have 1m-flexible-silencers on both the supply and extract from the dwelling. And I have bought a supply manifold which has extra baffling inside too. The ducting is semi-flexible and radial, so no cross talk and I used the wider (90mm external diamater) ducts rather than the smaller ones (75mm external diameter). The expert who sold me the system said that my system should indeed by whisper quiet and the marginal increase in cost will be modest.

I have a copy of the 2017 Sunamp manual. Here's (part of) the replaceable parts list. Could it be the "Heater cartridge 2.8 kW x 250 mm"? Message me if you want a copy of the whole manual.

I wonder if it is worth simply writing to the council citing the relevant time limits and appropriate sections and simply stating that you now deem approval to have been granted as it has timed out. And let them contradict you if that is not so. You could add something like: "if I do not hear from you by X then I shall deem approval to have been granted" or such like. In my situation, when I did this on a planning condition, my planning officer was kind enough to play along and mark the condition as approved in the system. He did not seem at all surprised that the particular domain specialist in the council (trees in my case) did not provide any comments within the time limit. And he was probably relieved to have one fewer issues to deal with himself. He also told me that I was the first person in his experience to use this mechanism. Just my tuppence.

Thanks all! Marvellous. That's really helpful advice. I think that my first try will be: sacrificial timber inside, tape outside, and a fine hack saw.