Norbert

This detail is taken from the MBC documentation showing the web joist for intermediate floors and walls. Similar to many other manufacturers I assume. My questions are : What happens between the joists? Presumably there is there some other kind of infill with the panel above sitting on the joists where is the VCL around the joist? Does it somehow wrap around the end of the joist or is there extensive tape sealing around it

hmmmm..... while i do not feel the need to have any type of fire in our new build (unlike Mrs...) I do wonder how we would get on in an extended power cut. After Arwen we were without power for 5 days, however with 2x wood burners and a gas hob we survived just fine. If the house was all electric what then? I guess a back up gas camping stove thingy would work OK-ish for cooking and hot drinks, but what about space heating? I can see that a 2-3kw bio ethanol burner might well plug the gap, what does anyone else do?

My spreadsheet attached. The first sheet is my dimensions to put into the spreadsheet Heat loss calculator.ods

We have recently got PP for demolition and rebuild, so now getting into detailed planning. House fabric and technology will be to a high standard (U .11 or .14 all around), good airtightness, MVHR, ASHP for UFH and DHW, PV on roof, battery etc. I have completed Jeremy Harris's spreadsheet which indicates that a 5kw ASHP will be all that is needed, even over sized. I understand that open loop, minimal or no zoning and weather compensation is the most efficient way of running it. The house will have upstairs lounge, study, bedroom and bathroom. Downstairs kitchen/dining.family, bedroom with en-suite, WC and plant room. We recently had the opportunity to live in a friends PH while they were on holiday which was very useful. We had the main open plan kitchen/diner/lounge at a constant 20C. All other doors kept closed, bedrooms and bathrooms settled at 16C (perhaps a bigger difference than I expected), that suited us, we do not like hot bedrooms. So to our future house, I would like some advice on heating options. Given that the lounge is upstairs I feel that we cannot rely on UFH downstairs for that. So options are UFH upstairs in lounge and perhaps study as well, OR second A2A heat pump that would supply heat on demand and could also do cooling in summer using surplus PV. Then to bathrooms. I think 16C in a bathroom is perfectly OK for most of the time. It seems overkill to have UFH and 20C all the time. What would be useful would be to have the ability to add extra heat as needed for shortish periods, either manual or timed. This would need to be responsive which UFH would not be. Options would appear to be: Electric towel rads on a cut out timer, put on say 1hr in advance Towel rads driven by ASHP (but would that need a higher temp than the UFH?, could that be driven by the DHW temp of 45/50?) Electric wall panel heater, perhaps IR delivering instant heat any other options to consider?

Yes they are still in business and fully booked until the autumn, but the are only a small company, perhaps they were away on site.

Eden Insulation in Appleby also use I beams in their cassettes. Panel Construction | Eden Insulation Ltd

Yes I can see that motorised is better on all counts, and we will be going for that. I was thinking of manual operation as a backup in the event of failure or power cut.

I guess I am thinking of power cuts, failure of motors etc. Yes I am probably over thinking it

I have been looking at the Trojan exterior blinds, they are exactly the sort of thing I want to use. I see than can be motor or manual controlled. The latter would need penetration of the thermal envelope by every window. I guess it is difficult to get a proper airtight seal around a rotating shaft, but not impossible. Has anyone done this in a high spec airtight house, or do you rely on motorised control?

OK thanks. However I think I will go with traditional wiring and distributed automation. It takes 2 min to put a relay behind a switch, and another 2 min to take it out and revert to trad if you want to. Can't see a problem with walking round the house to do this.

Just connect S1 and S2 to the switch, either way around, it makes no difference. The relay just detects change of state of the switch. I imagine that there is not 230V going via the switch, something more subtle.

My new build will have an insulated suspended timber floor on block walls (to get above flood level). Floor will be I beams or metal web, 300mm plus insulation with decking on top, fitted by TF manufacturer My natural inclination is to minimise wet trades within the TF, so looking at dry UFH installations. These consist of pre routed pipe runs. Several manufacturers do these for instance : OMNI, Cellecta and Timolean, there are probably others. Bespoke dry panel heating cooling construction products for OEM. (timoleon.co.uk) https://www.cellecta.co.uk/product/mojave-s1-3/ and https://www.cellecta.co.uk/product/xflo-ff-2/ Omni https://omnie.co.uk/torfloor2/ https://omnie.co.uk/foilboard-suspended/ Does anyone have any experience of these products? Or am I on the wrong track here, should I just go for a screed on top of the decking? Any views welcome.

Given that the price of these FCUs are very similar to A2A heat pumps, why not have these instead? It may well be a simpler install.

Yes, I have used these. Very easy to install and they work faultlessly. The only downside is that without a Neutral they do not act as a "router", i.e. end point only, so they do not help to strengthen the Zigbee mesh. Using the S1/S2 terminals wired to a normal switch causes the switch to flip the state of the relay, so everything works just as normal. The only difference is that you get a double tick sound, one from the normal switch and one from the relay, almost but not quite simultaneously.

Reviving this old thread and going back to the point made by the OP. I have done a trial with various smart devices in my current house prior to starting my new build, so that I understood it and could decide what I wanted to do in the new house. I have used Sonof relays and movement detectors, smart bulbs, smart plugs all controlled by Home Assistant running on a Pi and Zigbee dongle. Everything works great. Simple to set up So what about the wiring on the newbuild? Based on current experience I have decided as follows : 1) traditional lighting wiring with all switches daisy chained 2) No double switching in halls and stairs, there is no need with automation 3) Live and neutral taken to every light switch 4) Deep plastic backbox (so relay can be put behind, and good reception of Zigbee wifi All of this can be put in and used as normal, plus reverted to normal wiring without any problem. Then to make it smart put a zigbee relay behind every switch, then the relay can be operated via the switch as normal, or automated and programmed using HA and whatever sensors you want. Having a Neutral available makes the relay capable of being a "router" i.e the more of these you have forming a good mesh the better the reception and communication through the Zigbee network. So having decided on that I cannot see the benefit of wiring all switches back to a central point in the plant room? Can someone explain why that may be better?