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£2 a tube should be telling you something when the others mentioned here go up to £14!

oh no! what have I started?

Our valuation surveyor (mid-build) said "eco-houses" should do very well going forward. Maybe an outlier as there's still some dinosaurs but I definitely think the cost of energy will be changing people's views on sustainable housing and adding an extra few grand to what they're willing to pay.

The energy market is a mess, but I'm not sure denying them a few "free" kWh per month is going to change anything. Paying more upfront to install a less efficient system in order to deny this export feels like sociopathy.

Photographic evidence of build quality (insulation levels, dealing at junctions, preventing thermal bridging etc) is now part of the Building Regs. Requirement of the 'new' 2021 Approved Doc L, effective mid 2022, for all new dwellings.

Not sure where you are getting your electric or gas from, gas is 10p and electric 34p. With a Heat pump and a CoP of 3, that's around £5 a day not £24.

Hope you have the floor well insulated, otherwise heating could cost you more instead of less. Just to throw another spanner in the works.

We had a comprehensive SAP report done and from this the timber kit company had a report produced with recommendations. The SAP report was based on the as designed at the time but since then I’ve improved the floor insulation and gone with 3G instead of 2G throughout. It also assumed an as designed air change of 3.0 where my aim is to get under 1.0. I also plugged the numbers into Jeremy’s spreadsheet and the total heat loss in the worst scenario is 3.6kW which more or less tallies with the detailed SAP report. Consequently the ME guys recommended a minimum size ASHP of 6.8kW so we specced an 8.5kW Ecodan and this is what the installer also recommended. However the installer emailed me today and said that they’ve reviewed how they do their calcs after feedback they received and it means they now recommend we go to the next size Ecodan up so 11kW, the difference in price is only a few hundred quid. I called the ME guy that did our report and he said that doesn’t make any sense to him and recommends we stick to the 8.5kW. I’ve got a copy of the spreadsheet the installer uses so will plug our figures into that and see what it says but my expectation is it will match what I already have.

OK did a little more research: As per Approved Documents Cover Page, these documents contain: * general guidance on the performance expected of materials and building work in order to comply with the building regulations * practical examples and solutions on how to achieve compliance for some of the more common building situations So indeed they are not legally binding. Instead the actual law - Schedule 1 - Requirements item M4: Access to and use of dwellings, Category 1- visitable dwelling M4(1). Reasonable provision must be made for people to— (a) gain access to; and (b) use, the dwelling and its facilities It is abundantly clear that it's unreasonable to expect every single socket (especially those in effectively fixed use) should be accessible. Instead, a reasonable amount of sockets and switches should be at that height between 450 and 1200mm.

This is exactly why I am looking at separate sockets.

No clue sorry!

What potential danger would be caused by this given the loads are fixed. Overcurrent (not short circuit) protection can be omitted for a fixed load if necessary. Not true. It’s standard practice to fit an infused spur off a 32A ring final circuit using a cable only rated at 27A best case. Also standard practice to connect an oven/hob flex - perhaps 2.5mm2 or less, to a 6mm2 T&E on a 32A circuit with no further fuse. Double sockets are usually only rated to 20A, so this is a bad idea. 2 single sockets would be ok. Better still, just have your electrician fit a dual appliance outlet plate.

you can see your current firmware version from the web browser:

I ran a Pi for several years non-stop without problems - though only converting BBC DASH audio streams, not writing to the card. I'm currently planning to use one again, this time for monitoring and enhancing the control of UFCH (in conjunction with a Shelly Pro 4). For me, the advantages are the ability to easily mount a Pi on a DIN rail in a consumer unit (more-or-less essential for this project), and the availability of the PiJuice to bridge short power outages and handle associated shutdowns and restarts (though I've not tried it yet), without worrying about heat. I may upgrade from an SD card to an mSATA SSD using the Geekworm X850 (or similar) shield to add robustness. In other circumstances I may choose a different option, so I'm watching this discussion with interest.

Yes - it was just for me because I am a bit special .

In hand ( not in situ ) plug a spigot into a fitting and test it a few times . If you find it easy to dismount ( remember not in situ - so will be easier anyway ) then go for it . If after 5 attempts and swearing - you might decide otherwise 😁

Set the hob to the highest power it can go, connect the hob (with a suitably larger cable) and the oven, both hard wired to a dual flex cooker outlet from the existing feed. https://www.tlc-direct.co.uk/Products/AA45DCOP.html

Ah so you are not actually paying 50p, that is what confused me.

Just to throw it in there ours is 6m wide and 4m deep. In the roof, fully insulated. It houses gas boiler big buffer and MVHR unit, but mostly full of stuff used as as store. Also have a fully insulated water shed, with all the borehole electrics, filters etc, 2.4m X 1.2m, this will soon house the ASHP expansion vessel, manifold and some electrics.

2Bs are around 1½W. It's the RPI4s that take ~5W.

Yes !

ok. sounds like an interesting rule. might go with the 15mm short pipe to 15mm -> 10mm reducer then. at least i can remove it even if it does cost me a few extra pounds per connection

Ah right ! Didn’t realise this was going straight into your manifold - just assumed another ‘cheap’ hep20 fitting . Don’t use spigot on manifold , new rule 🙄👍😎🤣

Yes . The ‘funny’ end just goes straight into any hep20 fitting 👍. Too slow @Nickfromwales

Wall drain is the way to go!

+1 to that. It is now down to the SAP assessor to police this, not something they signed up for as this is a Building Control function. In the absence of this photographic evidence assessors must revert to default SAP numbers at which point the house will probably fail under Appr Doc L and the assessor is the messenger (who probably will be shot!). Because of this, and a whole raft of other admin procedures, I will let my SAP assessor status lapse in the next few months.

Maybe think along the lines of exporting surplus to the grid helps you local hospital or school run on greener electricity. Your DNO doesnt trade in electricity so they're not taking the mickey.

Never one to miss an opportunity for analysis:

I think part of the problem about airtightness is too much trust in the techniques used. Examples being: "We parked the walls" "All internal walls are plastered" "The windows were taped" "All insulation is sheet/board" "It is timber frame" "The VCL is the airtight barrier" "The whole house is covered in Tyvek" "It is triple glazed" Non of those are inherently airtight. As others have said, it is the interfaces that are important, and they get covered up very quickly and cannot be visually checked after the event. Then there is twats with drills.

Each loop is a single length of pipe, buried in concrete, once installed and covered in concrete very little to go wrong. During the concrete pour the pipe will be pressurised with air or water, so not likely to get damaged. Manifold is just a series of flow meter and either a manual or actuated valve for each loop - all pretty simple stuff. Much more likely to put a screw through a pipe hidden in a wall than a pipe under 50 plus mm of concrete.

Just because you can though, in my opinion, why would you go for radiators instead of ufh? Why take up valuable wall space with over sized radiators that won’t often be used when you can hide it all under the floor and keep it out of sight. Radiators just don’t make sense to me in a modern well built house. with the obvious luxury of a towel radiator in a bathroom to that warm fluffy towel to wrap yourself in post cleaning.

I don't know where you are but it's capped at 33p per kWh here. If the required 48kWh was delivered with an ASHP at a COP of 3, that's 16kWh of electricity at a cost of £5.28 That is not so bad is it?77 EDIT: JohnMo beat me to it posting the same thing.

They should be taking outside air in via a dedicated inlet. Also the stove needs to take all air from this duct, some don't

Agreed as regards HP size if it modulates down (which some will). I also speculated that some may also turn up flow temp as a further bid for faster response time, which incurs an efficiency penalty of perhaps 2-4% per deg C based on some modelling posted in another thread.

A self-builder is more than capable ( most do anyways ) of documenting, with pictures, the methods of construction for the dwelling. Fabric standards etc become irrefutable then, plus the seller would then be able to show statistical data from the solar inverter / electric bills etc and effectively ( and factually ) demonstrate the very low running costs of the property as actual facts / figures. Selling with these credentials should sort the wheat from the chaff. Soon there will be a better clientele, but better builders will need to come first.

If you are putting in a beam to replace the wall then not much else needed. Timber joining plates are often called mending placing plates similar to this that you screw or bolt across a joint, hedgehog plates aren’t practical with the timbers in situ.

Surely there may or may not be an efficiency penalty? If a smaller unit can modulate down to lower output powers than a larger unit then yes, there will be an efficiency penalty with the larger unit. But if minimum power is the same either way then I don't see anything to cause an efficiency penalty.

Exactly. 99% of buyers will have no idea what a passive house is. Many will now care a bit more about how much it costs to run so sticking the utility bills under their nose will be a good selling point. I can see old draughty expensive to run houses becoming harder to sell if energy costs and interest rates remain high.

I believe the term being discussed at the time was "eco" house. If I ever sell ours, my focus will be on getting our energy bills in front of potential buyers. Passivhaus doesn't mean as much to most as very low bills.

When we sold our PH, not certified, in 2021 we had several buyers bidding against each other for the house, which sold for way above the asking price.

I totally agree, a PH will have lots of proof that it was built well and correctly. The problem is educating people, especially estate agents

14 years and counting! lol Heres a detail i've found: https://polyfoamxps.co.uk/wp-content/uploads/10-Bel-DPC-Wall-susp-fl-junc-detail-showing-PF-at-door-threshold-Option-1.pdf

You’re doing good . Some of us are lifers .

Welcome to BuildHub Adam. The best way of getting fast feedback is to find the right sub-forum, and post a specific question there. If you have photos and/or drawings (especially sections for something like you're discussing), that will usually help a lot.

I'm curious why you consider grid export a "luxury"? To achieve the same level of utility, an off-grid inverter will cost more.

Welcome to the group. Ask away I'm awaiting a delivery.

While the other replies are technically correct In most installs, there's no such thing as "actively" choosing to send it back to the grid. You connect the "grid tied" inverter to the consumer unit, and it generates as much AC as it can from the solar radiation available. The inverter doesn't care where that goes, whether it's either into your kettle or your neighbour's. At the end of the day all the sockets and appliances on your street are directly wired to one another via the mains supply down the street. The only way to stop energy export is to have a non grid tied inverter (meaning your household electrics are not directly on the grid) or install active export limitation. Both of these require most equipment (so more installation cost) than just hooking up grid tie and letting excess go out to the grid. But yes, if you do this the unused solar power goes same place as it would have if you didn't have PV panels in the first place.

@eandg Might be too late. I’ve got the detail for this now I can share with you. I also came across this book which has the detailing you’re asking for. One thing that did catch my eye quickly skimming through the book is that for board on board the heart wood should face inwards on the inside boards and outwards on the outside boards. This helps the boards make a better contact should they shrink.

We are quite luck in the sense that we have an upstairs plant room that is about 53m2 (9.5mx5.6m). It was designed to be right in the centre of the house, so wiring, plumbing and MVHR runs are radial in nature, hopefully keeping the length of runs minimised. The area was completely clear so I’ve created some skeletal walls from unistrut, with traywork to carry the wiring, plumbing and ventilation. This saved drilling holes in the plastered walls, which is my airtight barrier and the architectural brickwork. Plus if you have to move anything, you aren’t left with an unsightly hole. I’ve also started to create some partition walls (out of unistrut). It also means you have access to both side to run cables etc. I’ve only got the plumbing in so far, but it seems to be working out quite well (see pics). I don’t see why it wouldn’t work out in a smaller area.

just a quick post to share some of my issues which in hindsight are entirely self inflicted, hopefully this will help others not to make the same mistakes. 1. Put your waterpipe in the duct from the outset, soo much easier than pulling it through later. (I did consider it but dismissed it as wasn't sure exactly where my duct was going to come up at the time) - don't be like me! I tried pushing 30 odd metres of mdpe through a 63mm duct, got 25m through then nothing. I dug two holes to find it, ended up having to attach rope to car - not gonna lie, it was a griz and I was hating life. 2. When laying your hardcore sub-base for an insulated slab do the foul drain runs at the same time. I was under time pressure to get ready for concrete so I just left stubs poking out to connect to later - dont do it, I've made life so much harder for myself having to dig through hardcore to do it. 3. If you ignore no.2 and just leave stubs make sure you leave a good length - i didn't! The stubs i left only just poke out from under the slab, god only knows why I did this. I have spent all day yesterday and today digging them out so I can put an extension length on to bring them out to roughly where the ICs will be. Digging through the hardcore really sucks ass. Yesterday wasnt too bad, today was on another level. The trench kept collapsing in on itself and my 600mm trench ended up about 1.5m wide - a very bad day today. Dont be a plonker like me. I've made other rookie errors so far but fairly painless. These have been a right PITA.