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Gah, well this got on my mind so I went down a rabbit hole. There's a whole range of solutions out there: https://www.mastermover.com/applications/bin-mover https://bintowa.com/ https://www.industar.co.uk/product/tow-tugs-electric-movers/small/ https://wheelieezy.com.au/ https://emoveit.com.au/product/wheelie-bin-aluminium-trailers-3-x-240l-bins All look pricey or need a car/buggy but if its the difference between using the plot or not maybe worth it as a last resort.

Where precision/accuracy/sharpness matters people want to use things that they are comfortable with.

I expect there is a much simpler solution to this but I've seen someone on youtube build little motorised trolleys for their bins to take them out front. If you get stuck on this then something to consider. Having said that the one I've seen was based on a guide track and simple motors. If you don't own the road and can't alter it then you'd need something more sophisticated (and the more sophisticated the more difficult I guess it would be to get approval). I'd guess all you need is for something to make it easier for a less able person to move the bin.

@SimonD Is this available online somewhere? I've found https://waterregsuk.co.uk but that doesn't seem to have the same content as the photo you posted.

sorry, was saying it in the context of multiple acceptable solutions as discussed above. Informed specifier has the leeway to allow the installers choice of options within an acceptable basket but say no to crap options.

So everything leading towards pipe in pipe sandwiched at the join between eps and pir (likely chased into eps). so you get: - pipes insulated by the eps pir sandwich - spaced to separate hot and cold - individually ducted for easy replacement if needed - minimal disturbance to the insulation. Ie cutting is way less than 50mm Though as @saveasteading is paying someone to do this maybe the biggest decider is what his installer is most comfortable with?

My only experience with low energy input is when my last boiler failed and I used the immersion. 3kw rated immersion seemed to have no trouble getting my 170L tank up to temp within an hour (from too cold to shower to plenty warm enough - can't be more precise than that).

Thanks for the update and I'm glad you are trying this. I assume with the controller still in the upper bedroom? If our guesses about your building are correct, it will take some time to warm. So while you are running this experiment I suggest the following: 1. Keep internal doors open - you want the air to be able to move around to equalise all the internal space* 2. Daily, open the windows for a good ten minutes to ensure the place has a good blow through (I think you said you did this anyway). 3. Regularly check the radiators with a thermometer ideally something like this: https://www.amazon.co.uk/ERICKHILL-Thermometer-Non-Contact-Adjustable-Emissivity/dp/B0C72MDQ2Z?crid=2V242L59HQZZ8&sprefix=ir%2Bthermom%2Caps%2C225&sr=8-6&th=1 The radiators should be warm and at approximately the same temperature (guessing around 50C) if the room with the thermostat in it is colder than 16C. If some radiators are colder than others or if the radiators are often not hot then there may be a problem with the system that needs fixing before things will warm up. *If you get hot at night or if you leave the bedroom window open at night, close the bedroom door to isolate the room from the rest of the house. You can also turn that specific radiator off at night and back on in the morning if it helps with bedroom temp (a good idea if you have the window open anyway). I know you said you will try this for 2 months but if you don't feel things improving at all in 2 weeks then maybe come back then.

My remaining thoughts are that I think I would want a duct, rather than direct bury. I'd want to be able to swap things out if there was a problem. If you are willing to put on top of the 150mm eps, then insulation not so needed. Could run individual pipes in conduit then so you could always pull/replace the pipes (like they do in many european countries). Much lower profile this way too.* I'm sure you've got another duct going in for electric stuff but I would try and put at least one more in for future needs. Probably won't use it but if a future need develops and you haven't got it then you are in a world of pain. * No expert so don't know if there is a flaw in this approach I'm not thinking of.

https://barkeepersfriend.com/

DHW definitely the limiting factor, depends how you design your system whether it's an issue. If the tank is big enough to handle the morning (or evening) routine in one hit with room to spare then reheat even if long shouldn't matter too much, just comes down to scheduling. If heat loss is 2.8kw, a 4kw unit can spend several hours a day on hot water (not all at once) and still have capacity to heat the house. Or have I missed something? This depends a lot on the heatpump though doesn't it? @JohnMo was talking about how his new 4kw heatpump had a much bigger external heat exchanger/radiator which should lead to a lot less icing/defrosting than his previous 6kw (downrated 9kw?) unit. Edit: I should add that Nick and Simon are the experts with experience, I'm not, just someone who is interested in this and trying to solidify my knowledge.

If these use the same internals then it's likely the minimum modulation is the same on both. If that's true then there is no benefit for going with the smaller model. Which means with a max heat loss of 2.8kw and a 7kw heatpump you will likely see a lot of cycling which is not great for efficiency. I feel like I'm channelling @JohnMo, surprised he hasn't spoken up yet.

Neither? Even 5kw sounds a bit big. Smaller heatpumps are available, Important to get one that can moderate it's output down a lot. Most of the year you'll need a lot less than 2.8kw

Any thought given to putting in a continuous layer of the 150mm eps then putting the pipe with PIR insulation around/40mm? on top (foamed in)

and I'm not stopping... This is stuff you have actucally bought and checked is 13mm? I ask, because the photo shows a pipe with insulation that looks thinner than the inner diameter of the tube. 16mm tube, 12mm inner diameter. Edit: Basically the photo looks identical to the ones advertising pipes with 7mm

Agree, not how I look at it but I think most people think about touch points, so expensive fixtures and fittings that feel luxury (eg solid metal rather than plastic and name brand 'premium' appliances, etc.

My reading was lots of insulation on top of the duct, none below. I assume there would be free air in the duct also. Edit: and the MLCP stuff I was looking at was 7mm insulation. Not sure I saw any when I was looking with 13mm. Link please?

I think what they are getting at is that plastic pipes have some minimal insulative value compared to copper pipes. Nick was talking in another thread how condensation doesn't tend to form on uninsulated plastic pipes. But that by no means they are insulated. If you are putting these pipes on an uninsulated ground bearing slab then putting some decent insulation on them seems very sensible to me. Someone here warned me off the pre-insulated MLCP pipes as the insulation isn't very thick. So fine for some uses but not if you want a lot of insulation.

I read your post as suggesting a solution to @Dunc I can see that happening over a long period of time and I'd guess the glazing industry has data on this. But I very much doubt it's relevant on the timescales discussed in this thread.

That's not replacing the argon + seal. So even if it clears the view the window is still performing far worse than designed.

How many of you are living there now? Is this a case where they are designing to be plenty for a fully occupied house but most houses are occupied a fair bit below their theoretical maximum. I'd guess flats are often occupied much closer to their theorectical maximum given house sharing and property costs in cities. So maybe there have been some problems in those types of properties leading to a rethink.

As always depends on your situation. Short runs from the manifold? Especially if run with smaller diameter pipe (10mm copper, hep2o plastic, etc), don't need HRC. If you have long runs, especially of 15mm+ pipe then HRC may make sense. I can't find it right now but there was an online calculator/diagram that someone posted before that would neatly show how quickly a tap would take to warm up given length of pipe + pipe diameter. Maybe most of your sinks are close to the manifold so won't need HRC but one is a long way away and for that one you want a HRC (connected to PIR in the room so it only runs when someone is near the tap).

I don't know how your browse activity on here but if like me you use the activity view then switching it to the condensed version makes it a little better if you want to ignore things (or even just not see every update).

Congratulations. This has been a masterclass in successful self building by managing contractors! More important than that is the contractor selection, project management, etc, and I think it's you (with assist from Mrs P) that has done that so you can feel great satisfaction with how this project has gone. I'm guessing (maybe you said before) your background is in project management and if not it's an even greater achievement. When you have time and if you have the energy I and I'm sure many others on here would appreciate it if you could share as much as you can on your process for managing this project. What your average day looked like, tips and tricks, preparation, etc. I think this could be really useful for those of us with less project management experience!

£70 a month (£840 per year) no, as I've said before I think there is a decent improvement to be had for not ridiculous money. As I've said my mums uninsulated house with an inefficient gas setup and various other problems costs about £2000 per year to keep at around 20 during the day but they let it get cold overnight). I do think it's possible for zoot to be much more comfortable for an affordable amount extra per year, at least as a trial. If zoot has money to consider ripping up his concrete floor and replacing it he has the money to try this. Maybe he doesn't have it to run long term but having the information about what it takes to warm the house can direct him to the most cost effective improvements to lower those bills. Right now it's finger in the air guesswork. I've not given up yet but I do understand where you are coming from. I hope zoot will agree to try it for a period of time. If it works then we can have a conversation about whats next. But fundamentally zoot doesn't believe this stuff and words on a screen aren't going to change his mind. Being warm in his house might.