-rick-

and this is not just making a joke. It’s likely that the training corpus for the llms has the best responses in relation to professionals who don’t tend to use that language. By swearing at it you likely trigger different statistical paths within the training that have less optimal outcomes.

maybe swearing at a computer program isn’t the most effective tactic

I think you’ve missed a key part of the specification which is to keep @Pocster occupied and provide an easy distraction from finishing his house. Everything following that is just part of the journey. 😜

sure, but yet if you look at what’s offered commercially as solutions to insulated rafts. You have some companies (eg kore) offering standard starting points of 100mm slabs with thickened sections and relatively limited rebar vs isoquick with 250mm single thickness slabs with tons of rebar. Afaik for equivalent ground conditions. Now it may well be that isoquick is designed to allow for a more diverse range of ground conditions ‘off the shelf’ vs kore that would get bulkier in some. But if you go with isoquick for ground conditions that work with the standard kore then you’ve used significantly more concrete and steel for the same (and labour to install the rebar) than kore. absolutely interesting point. Noted agreed. One of the reasons I lean towards paying others to get to level slab and doing much more myself after that point. Yep. Seems like the easiest way to get in a mess with building projects is to design as you go/start with rough detail and plan to flesh out as you get to each stage. Unfortunately seems like an all to common approach for people.

good idea. Cheap enough that you could buy now to trial before you spend money on plumbing the house.

hopefully someone has the time to do the maths or get Ai to do it. But my guess is that water at 15-16C has nowhere near enough potential cooling in it to strip the humidity out of incoming humid air before the MHVR. (Dehumidifying humid air uses a similar amount of energy to cooling it). The MHVR can do effective bulk dehumidification but only to a limit. So my thought is let it do that for free then use the coils to take a bit more off the top once the MHVR has done as much as it can.

Agree with that thought. let the mhvr do the bulk to the dehumidification for free. The coil just does the top off. It means the temp difference between the water and air will be lower so less effective. But there’s no way near dew point water will be able to suck much out of the air but even a small amount might be enough.

I think it’s well established that a hydronic heat exchanger in line with the MHVR doesn’t really have the oomph for real heating and cooling. I’d always thought to add a smallish one anyway with the hope of maybe bringing the mhvr output air temp above/below* the ambient internal temp vs just below/above* due to mhvr efficiency. Thinking being that not every room would be exposed to ufh so the mhvr coil would just help distribute the heat/cool more widely (Wouldn’t even think about it if couldn’t find a suitable cheap coil) This thread has made me wonder if that coil might have a useful dehumidifier aspect during heatwaves like this. If you are running the flow temp low enough to cause condensation on the floor then inevitably the exposed coils in the heat exchanger would be cooler than the floor and attract more condensation. If running only a touch below dew point then maybe the excess moisture preferentially condenses in the mhvr coil and prevents condensate forming on the floors. So not full bore dehumidification but just enough to allow you to lower the floor temp a degree or two more than you otherwise would. Does this stand up to reality? * depending on whether you are heating or cooling (in that order)

Depends on your unit. They can be between 60 and 90% efficient. 33-24 = 9 9 x 0.1 = 0.9 0.9 + 24 = 24.9 incoming temp in the 90% efficient case? (not 100% sure I've done this right but you get the idea). The air from outside will inevitably be warmer than the inside air in this situation, but would be much less warm than just opening the windows and blowing the outside air in.

Definitely an important point (which was the caveat in my previous statement though not expressed as such). I'm always thinking about keeping the details to something I would be able to do myself. If/when it comes to the build I don't intend to do everything (though a substantial part) but by keeping that in mind I want to keep the options open depending on contractors and skills available when it comes to it. Having said that, laying UFH is very DIYable and likely to lead to a better result than an uncaring contractor. Installing rebar on the other hand is more challenging and have a contractor come in with lots of heavy rebar after the UFH is laid would be a reason not to do it that way. This is a good point, I've tended to lean the other way (less concrete/rebar if possible) in order to keep the embedded carbon down. Though a thicker simpler slab is likely easier.

AFAIK the concern is mainly structural damage caused by damp. But also a concern that a damp area might be make a good home for mould. Short term none. Long term, maybe there's more condensation that you don't see that will cause damage given enough time.

It's maybe not the most efficient way to organise things, but only really needed for extended heatwaves. Reducing the humidity will definitely affect how it feels, but also lower the dew point that would allow you to drop the water temp running through the floor without worrying about condensation, so you could get more cooling from that system. Time to insulate those pipes! Waste of money heating/cooling the loft.

This has been quite commonly done by people on this forum building highly insulated homes. Idea being you design the home to be a stable temperature and the slow response can be used to your advantage by loading in the heat when it's cheapest and letting the floor buffer the output over the day. Putting coils anywhere in a 150mm+ slab is not going to lead to a fast response anyway (need a insulated screed for that) so burying the pipes lower also minimises the chance of damage later and debatably is easier to install. I can't remember all the arguments for this method made by others off-hand, but do know that after reading thoroughly here I'd been persuaded that I'd likely go that way if/when I come do this. (dependent on installation sequencing).

A dehumidifier could do the same job and they are pretty cheap. Wouldn't the ERV help even in these conditions, slowing the rise of humidity caused by outside air vs a HRV which would just dump all that humidity straight inside?

They have API integration to inverters. On those with full integration I'd guess they have full reporting from the inverters. But they also support less integration and I think they can still support those because when signing up you give them permission to access the 30min readings from your smart meter. So they can see how much you export within those high reward periods (and this acts as verification for the API integrated case).