Mr Blobby

Is there any reason why I shouldn't put the extract manifold on to of the supply manifold in the picture? Unit is on the loft. Plenty of room but would use less space if stacked. I ask because every installation and design I've seen has the manifolds adjacent to each other.

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I don't think your house was rendered when we visited. It is reassuring that you are happy with the sto rend on your build. I guess ours would have a different base coat on a block build? Which sto product did you use? Yes please PM me Kevin's details. This rendering looks dead easy. I think I'll just do it myself in an afternoon and save a bucket of cash. 👍

Thanks @nod, this is exactly as I suspected. I like my builder but he does love to do things as cheaply as possible. You think K rend is ok then? With the proper backing coat, which I assume is the first (of two?) coats over the blocks? And would that typically have mesh in it? (I am neurotic about cracking)

For us we have screed going on top of hollowcore slabs so easy to lay the UFH pipe. I just don't know how we'd plumb in a second manifold without adding another pump. In our passive house I agree that first floor UFH is probaply unecessary. Our builder struggles to understand this however, and keeps telling me we should put the UFH pipes in the bathroom floor so the tiles aren't cold in the morning. Is he right? Will the floor be cold?

Our thoughts exactly. The world has changed since we did our original kitchen design with two integrated ovens. Counter-top air fryer and microwave just seems to make more sense for us now.

Sorry to hijack this a bit... @Conor, Do you mean an integrated air fryer? We are thinking of dropping our planned combi microwave/air fryer for simpler stand-alone units on the worktop in the pantry. ... I agree with other comments on here, hob on island, sink behind is a good layout.

We need to decide on render to go on block house. Our builder is a big fan of K Rend, but I'm not so sure, having read horror stories about algae growth etc. Also builder says he puts down a base sand/cement layer and then sprays K rend on top. I did ask him about mesh to resist cracking but this doesn't seem to feature in his approach, leaving me a little concerned. So what are the other options? And then there are options within options, like monocouche, silicate? What about sto, or weber? I have no idea about this so please help!

Our builder keeps telling me I should put some UFH loops under first floor bathrooms to have a warm floor. Should I? And if so, then how is that connected when running an otherwise very simple single-zone system with no additional pumps? A second manifold in series?

No. I remember our M and E consultants tried to persuade to install a combined buffer/DHW tank some time ago. I didn't like the idea then and still don't. Call me old fashoined but I like to keep these things seperate. And also at 285L DHW maximum capacity is perhaps a little smaller than we would like. And now it looks like we will bin the buffer all together and go for a single zone UFH.

What flow meter do you use? What do you use to read the data?

Why are you running a branched ductwork? Far better and easier to install with zhender manifolds with attenuators on top of the zhender unit and then 90mm semi rigid ducting to each of the rooms. And probably less noise transmission between rooms (hence all the silencers in the ducts on your plans) Is your loft space warm and inside the airtight envelope? If not then do not even think about putting the unit in the loft space, too much hassle insulating ductwork and sealing penetrations.

So the water pump in a panasonic heat pump can push water all the way round the ufh loops? That would be good. For some reason I just imagined it would be too feeble. We know our heat loss calcs and 95% ruled out UFH upstairs except possibly to add a bit of cooling. Just in case. Agree that fan coils better, maybe need to think about this some more. Maybe one or two upstairs above dew point at UFH temps to avoid condensate drain. External blinds will hopefully control the worst of any overheating but we only have this one chance to put the pipes in now for extra cooling, just in case. So your ashp water pump controls flow rate through the UFH loops? ... Its funny how the decision to install a buffer tank was cast in stone two years ago but is now, like so mamy other decisons, going to change. Keeping it simple and running a single zone without any actuators or additional pumps is very appealing. Apart from the cost, it just seems like a better way to do it.

Our heating system is currently designed for ground floor UFH and ASHP. So far so good. It has always been in the plan to fit a buffer tank. I'm now beginning to re-think the buffer tank and remove zoning. To give some context, we have a block house on insulated slab and <3kW peak heating load. Floor temperature will change very slowly hence individual zone control seems to make little sense, even with solar gain moving around the house. We have about 600 metres of UFH pipe in the floor at 200 centres. I see from discussion here that there is a school of thought that questions the conventional wisdom of installing a buffer tank to stop short cycling because there is already sufficient volume in system. And so it may be more efficient to remove the buffer tank all together and connect the ASHP diretly to the UFH manifold. Is this a contentious area, or is this well established? If we delete the buffer tank, are we then limited to a maximum of one UFH manifold? I am toying with the idea of another manifold on the First floor, but only for some additional cooling, or maybe heating under bathrooms. What about hydraulic separation? I would need a pump at the manifold of course, so what if this manifold pump runs at different flow rate than the ASHP pump? How does that work without seperation? If I did decide to add another manifolfd for some UFH upstairs, would that mean a buffer tank must be included? Our plumber will be horified at the suggestion of dropping the buffer tank, so I need to be certain of this before I give him his next heart attack.

I suspect part of the problem in GB is the rampant nimbyism that forces turbines off shore where generation costs are twice per KWh than onshore wind. Here in Ireland there seems far greater acceptance of turbines. Only about 2% of Irish wind generation is off-shore compared to about 50% for GB. Its ridiculous.

This is great in theory but in practice architects don't give a hoot about value engineering. During the design stage I asked my architect about costs and he flat out refused to comment and told me to appoint a QS to cost the project. Which is completely unhelpful. If I was building a house again I would get the SE and builder involved far earlier, to do a proper sanity check over the plans, and rely far less on the architect.

This. Do not ever pay a % fee. And get a builder to look over the plans before going to planning. We asked our 'passive house' architect for a simple design to passive house standard. We got big full height windows, parapet walls and voids, all costly to build and very bad for PHPP. Architects just can't help it. It's not their money so they will design in all sorts of unecessary crap.

Panels are on our roof but we haven't purchased the inverter yet. Theses are the panels we have on the roof. https://leisurepower.co.uk/solar/solar-panels/rigid/15139/10-x-aiko-455w-all-black-solar-panels-aik-a-mah54-455-ab-g2?gad_source=1&gclid=CjwKCAjwodC2BhAHEiwAE67hJIC4gQq28yAfvy0rndgda032mOLPHGcf0UW0m6trniTA3LBsW8jIqRoCGsUQAvD_BwE ... we purchased the panels from an installer who put them on the roof for us. We're very pleased with his work so far. We used S5 pvkit clamps onto standing seam. The UK suppliers only sold the old version so we ordered the new version 2.0 clamps direct from the US. Our installer can't source our chosen inverter within the UK but he is happy that we supply it and he installs it. This 3-phase hybrid inverter has been available on the continent for over a year but the last time I looked all the UK suppliers were selling the old series 5 model. Which is no good for us because we want the latest model with >2 MPPTs. https://etronixcenter.com/en/8176291-se307-solis-solis-s6-10kw-hybrid-inverter-compatible-with-pylontech-force-h2-hv-battery-including-logging-stick-wifi.html Yes its fully G98 compliant... https://connect-direct.energynetworks.org/device-databases/search-gen?model_number=S6-EH3P10K-H-EU We will be plugging in a pylontech H2 battery. Probably this one.... https://etronixcenter.com/en/8173159-pyl-h2-1421-pylontech-pylontech-force-h2-hv-system-1421kwh-1x-fc0500m-40s-v2-4x-fh9637.html ... and conected to this will be a couple of zappis. And maybe an Eddi.

It depends on your DNO. Here in Northern Ireland NIE are probably the least flexible. Temporary cabinets must be brick built and cannot be made perananet and meter cabinets must be in a permali box on the wall. I did try to reason with them but they were having none of it. Can you not make your temporary box permanent? That would have been my first choice if the DNO allowed it. There are no smart meters here and so the meter reader needs access to the meter, hence it is so restrictive. I assume it is more progressive in England so you will have more choice of where the meter goes.

Time of use tariffs will always be available. Here in Ireland (NI is part or the Irish market, not GB) demand falls off a cliff at night and wind generation is curtailed. Regardless of how many EVs are on the road there will always be a need for an incentive to shift load into the E7 hours. Little and often is ok if you don't do many miles. If I were to commute to Dublin three days a week then I would need to charge my 75 kW battery at 11 kW every night and that would only just fit inside the E7 window. (thankfully I don't do this any more, but I did in the past) The problem I found is that here in the UK the PV suppliers have no clue and don't want to sell 3P hybrid inverters. When I approached UK inverter suppliers they just wanted to flog me three single phase inverters, which is fiendishly complex and crazy expensive. There are plenty of good 3P G98 compliant inverters, its just that UK suppliers don't stock them and don't want to sell them, probably beacause there is too little demand here to make it worthwhile. Look overseas however and it is a different story. We are getting our 3P inverter from an EU supplier where there is lots of choice at good prices.

We have a temporary supply inside our boundary. The DNO laid the 3-phase cable into the temporary cabinet and a single phase is split off into the temporary meter in the temporary cabinet. In a few months time when we get the meter installed in the cabinet on the side of the house (which must be bigger than a standard permali box) then the DNO will joint underground to the cable already inside the boundary. No further excavation by the DNO required. For us the initial connection that required DNO excavation outside the boundary (which is typical of course) cost way more, about 2/3 total connection cost. If you can pay for it all up front in one bill then do so. The initial connection is vat free as a new connection but the second DNO bill to connect to the house is a change of existing supply and is not zero-rated for VAT.

Because we want the option to charge two EVs at the same time in an off-peak time-frame at 11 KW each if we need to. That's the 22kW gone. And then we may also want to heat the water in the same off-peak window. And maybe charge the batteries connected to the inverter as well. This isn't about using more electricity, its about being able to time-shift higher loads into an off-peak window, something that is cheaper and greener and better for network stability.

We have a 3-phase connection to our on-going build. We want 2 EV 3-phase chargers for two EVs (Tesla charge 11KW 3 phase if ever needed). We also also want to charge simultaneuosly off peak and maybe charge batteries simultaneously so the house load will be quite high. I think we have 3 100 amp fuses which the DNO had no problem with, so lots of headroom. Also 3P means its easy to install solar PV > 3.6kw limit without any hassle. For us the cost was only slightly more than single phase because of our location to the pole and cables. We are running all 3 phases into the house and balancing them and running a 3-phase hybrid inverter. Will be interesting. If the cost is not prohibitive then go 3-phase. Its more interesting too.

I have read that dips in ducts can gather condensation. Is this only an issue for exhaust ducts carrying moist air? To explain, we are running ductwork along the eaves in the warm loft but then changing direction 90 degress to run parallel to the ceiling joists to the MVHR manifold. At some time in the future we would like to board the centre of the loft hence we would need to dip the ductwork into the void in the ceiling joists and then bring back up into the loft space the other side of the roof. Hence the dip in the duct under under the boarded area. We only need to do this for two supply ducts so hopefully no condensation and no issue. Also, is it ok to run the ducts on top of 400 centre joists or board the loft at the eaves first? Or am I overthinking it?