-rick-

I was thinking a bit more rigorous than the standard as I'm not sure the standard pressure type testing would pick up a restriction/kink that easily (good for catching more servere damage). But it's hardly a huge deal to attach a circulating pump and measure flow/pressure.

Also worth checking that the immersion isn't coming on to suppliment hot water?

Just to be clear, my understanding of this statement is that one part of the building may end up higher/lower than other parts. You are not saying you expect a crack with a step of 25mm in the middle of the slab. Obviously the big crack in the middle of the slab would break UFH pipes but if you have a crack that big then it's likely big enough to affect more than one loop and certainly going to cause you many other problems. If its just the overall building moving then the pipes should be fine. They are designed to withstand normal concrete movement/expansion/contraction. The UFH pipes are designed to deal with this. Plastic has some flexibility. There are installation details you need to install around movement joints, etc. Plastic won't handle sharp cracks with significant movement but expansion/contraction measured in mm per m will be fine. There will always be bad contractors and poor installs. If you have a contractor that doesn't give a shit causing lots of problems then adding an extra loop or two to the design isn't going to save you. Given we are talking about decisions made at the design stage, rather than spending money on more loops, extra/larger manifolds and a less efficient system as a way to mitigate against a poor contractor you would be better off finding a better contractor/organising better supervision. Requiring a full flow test of each loop after install would be one way to ensure the pipes are good at install without adding a lot of extra steps (so long as your contract was tight enough to force the contractor to fix any issues). As I was saying the if the pipes are good at install then there is little that will go wrong in the following years. Getting a good install is a problem with any system (see the amount of people we have on here having issues with non-ufh heating systems). One caveat, if you install in a thin screed then there is always the possibility of putting a drill through a pipe but if you put drill through a pipe in a thin screed the process of repairing that is much easier than an unknown fault in a more deeply buried pipe and, unless you were the one drilling, someone else is paying for the repair. Firstly, UFH is laid with no joints. If there is a joint the only reason is that it is there because of a prior repair. I've seen others here talk about having a joint to fix a problem with long term success so the prospect of a joint failing (that only exists in case of prior error) doesn't seem to me to be a good reason to specify a more expensive, less efficient system up front. Sure, please take me through a scenario where a surveyor sees a problem that leads to a significant reduction (>5%) in the value of the house where that problem would have been prevented by installing extra UFH loops. It really depends on the layout. We are talking low energy homes here so any room shouldn't be losing more than 2kw of heat. Any room big enough to get close to that level of heat loss is likely big enough to have multiple loops in it anyway so at least some of the loss from a defective loop can likely be made up by increasing the flow rate to the remaining loop(s). So many options to make up the rest. Normal radiators, baseboard radiator (electric if water pipes too difficult to route), AC fan coil installed high up (or on other wall blowing air to where it's needed), an electric panel heater installed on the ceiling above the cool area raditating down (not a great idea but a possibility). These options vary from a few hundred to maybe 2k for the most difficult. Not enough to seriously affect the price of a house. The point I'm trying to make is that I'm not at all convinced that having an extra loop solves any of the issues you mentioned and that it comes with downsides. The likelihood of a spare loop being in just the right place to adequately cover for another failed loop is not high. If you install lots of short loops vs fewer long loops then you are adding quite an extra cost and potential efficiency loss/design complexity (how do you route all those pipes from the manifold without causing overheating?) and my argument is that this doesn't seem justified by the risk of loop failure. I was hoping my comments would solicit others to speak up as I don't have practical experience on this. I'm open to being convinced but I would like to see some detail to back up your argument. To reiterate, I am arguing from the perspective of a new install in a modern low energy home. Retrofit in a high energy home might be different (not really thought hard about it). What was the reason for failure?

Given the age I would guess you would be better off setting aside an amount to cover the cost of replacement (or make it a condition of sale) than investing in understanding its current state. Seeing your other thread, the most important thing is to make sure you have all the legal rights you need to maintain/replace any soakaway in future if needed.

Similar to my thoughts. There are some interesting plaster in profiles around that are worth looking at. Sorry, no links as it was a while ago, cost from cheap to ridiculous depending on your asthetic tastes. The other alternative I've looked at is doing similar but shining up (45o) from dropped ceiling details. Either way, conceptually I like the idea but when I've seen examples I've not been that impressed. I think a lot depends on the design and the other lighting in the room. Worth working up a prototype of this. If using volume controls (potentiometers I guess?) how will you integrate that into the drivers? Most controllers I've looked at (not a huge number) will either want mains dimming, instructions from a smart system (dmx, dali, knx, ethernet), a PWM signal or a 0-10V signal. None of which you get from a simple potentiometer without additional work. I'm pretty sure I've seen you post knowledgeable stuff about electronics before so I'm guessing you know this and were simplifying. But prototype definitely worth it in anycase. Worth planning on multiple power feed points to a strip. You can buy good high CRI CCT strips in much longer lengths than 5m giving you the flexibility to cut them up as desired. No harm in multiple power feeds (from the same controller) to a single continuous strip. Better to over provision than under. The fallback is standard 'smart' bulbs (Hue, etc).

I watch at 2x speed and don't mind skipping here and there. Makes a lot of youtube creators watchable when they otherwise wouldn't be.

Not sure that is what you were referring to earlier. Can't play the video as my ad-blocker seems to be interfering with it, but the text of the article seems to say to use Nest and that Tado is an on/off type controller (with the opentherm version withdrawn from sale in the UK).

Look again, he is running it with Opentherm with full Home Assistant integration. Though he says some of the details of that are in part 2 (which he hasn't released yet).

Good to be reminded of this (pretty sure I was previously aware but had forgotten). How do you find it? @Alan Ambrose Curious what your plans/thoughts are?

That was kinda what I was after but even with that a quick search of youtube doesn't bring up anything recent. Theres something from 3 years ago but I'm not sure I want to trust a 3 year old review as I think that's before Tado moved some of their stuff behind a subscription. Unrelated to the above but relevant to this thread. The below (very geeky) video from Cameron Grey was what caused me to pull the trigger on Wiser after thinking about it for over a year.

Damn it! I really should have waited. Could've saved a load. Not sure if the TRVs are really worth it. I got two, partly for temperature sensing but they seem to add complexity and not sure the wiser interface makes managing them great. Link?

I think these two statements is the crux of my disconnect with your points. With all UFH there is a potential for a kinked/damaged pipe during install but once the floor is down and the pipes are known intact then I don't think there is anything to worry about with them. If gunk gets in they can be cleaned. If some lump of metal gets stuck in there then that loop can be isolated and a mildly corrosive liquid can be put through the loop to dissolve the metal. PEX is pretty much inert and as long as it's intact once the concrete sets you shouldn't have issues. (If the concrete moves sufficiently to cause problems then you have a bigger issue than the pipes). I know there have been issues with some other materials used in the past, but PEX has been standard for a long time now and it's properties are well known. I still don't see why you would want redundancy in terms of extra loops. To me this is violating the idea of keeping things simple. We see a lot of designs on here that only have a few loops. If you want to build in loop redundancy you either add one more loop, which if you have to isolate one loop would still leave quite a large area unheated which is not a satisfactory answer or lots of extra loops which pushes up costs quite a bit and maybe reduces overall efficiency. My argument is that a failed loop (post install) is a very low probability and in the event it does happen having extra loops doesn't really buy you much over just running the system with a higher flow rate/temperature to compensate, neither option would likely be satisfactory. *A failed loop at install time likely leads to a repair being made before the concrete has fully hardened and certainly before any finished floor surfaces are laid. Over 50 years you would likely be replacing the heat source and controls 3-5 times. Each time flushing the system of any build up. I'd argue that over the life of the pipes the overall efficiency is likely to increase as technology improves and the mechanical/control aspects are replaced with newer technology. There is a limit to the amount of heat you can put in a floor due to finishes but if you've designed for low and slow then there should be a very siginifcant margin that could be used to compensate for other issues at the cost of efficiency before that being a factor. It entirely depends on the layout of the property. The cost of installing a rad is likely lower than digging up the floor to fix a damaged loop and there are lower cost electric options.

Installation couldn't be simpler if you already have all the right wiring setup. I removed my old dumb Honeywell controller and re-wired the base and installed the new one, only to realise that the Honeywell base was exactly the same and I didn't need to rewire anything. Basic setup in the app is easy, two annoyances: 1. The base doesn't support 5G wifi and I had to re-enable 2.4G to have it connect (this is the older V1 model that is currently being replaced by a V2 - partly why prices are getting discounted - but the V2 is more expensive and is sold as a more comprehensive smart home hub rather than a heating system. I think the wifi is the only real limitation that affects me. 2. The way they setup scheduling is frustrating to edit. Currently my system is still not fully set up as I want to change over to opentherm for CH while keeping the HW at a higher temp*. Because of this I'm still running the system in manual mode without the advanced features. Turning off all the scheduled times was time consuming. * I'm not 100% sure I can fully use opentherm in my setup. I know it's supported with combis but with a S-plan system boiler I need to verify things. Unfortunatetly my installer really ballsed up the wiring and I'm not even running properly as S-Plan right now (there is one signal line to the boiler, not two) and thats before adding opentherm cabling. Royal Mail literally just rang my door and walked away before I could get to it with my delivery of stuff needed to change the wiring over. So guess I now get that delivery on Monday and will be able to report back how things go later in the week.

Tado seem to want to charge a subscription for their AI features. I've just got a Wiser system whose advanced features are entirely free (at least at the moment). Not had it long enough to recommend but suggest you at least look at it before comittiing. Screwfix are selling it at a discount right now (wish I'd seen it when I bought mine). https://www.screwfix.com/p/drayton-wiser-wireless-heating-1-channel-thermostat-control-kit-white/7785v

'Infrared' in this context is marketing nonsense. There is a point to exposed infrared emitters but you are going to bury these emitters underneath other surfaces so the infrared emission properties will be of the surface not this graphene nonsense. Any electric underfloor heating will be the same efficiency as these graphene ones and likely cost a lot less. Electric UFH mats are really cheap and theres no reason to pay more. Now, electric UFH is a pretty poor way to heat a space, especially if the floor and house isn't well insulated but if you are only installing it as a way to take the edge off cold tiles then its running costs should be manageable with the right controls (ie, timers to limit its use to short periods).