jack

It needn't add anything to the costs, depending on your ASHP. The basic controller that came with ours has a basic display of consumption and (I think) COP for both heating modes. According to the MCS guy I used, that's sufficient.

...or the inlet and outlet are too close together on the outside of the building.

With a well-insulated house, sudden drops in external temps don't make any real difference. I have no idea what the temperature is outside unless I look at the weather forecast (or, you know, actually go outside!) Also, if the warm air is let out for some reason (eg, door left open), it very quickly recovers. That's part of the joy of UFH in a well-insulated house.

Welcome to BuildHub. A few thoughts: The UK doesn't have a history of ducted air heated and/or cooling in domestic settings. The concept of using aircon to warm a space just isn't in the consciousness of the general population or domestic electricians/plumbers whose opinions would usually be sought on heating matters. Subjectively, air heating tends to be considered less pleasant than radiant heating. Heating the air The air is very dry, which some people have physical reactions to. Also, while the air in a room can be heated up quickly, in my experience the room itself still won't feel comfortable until the furniture and walls have warmed up. That's a much longer process than heating the air. I'd be wary of solutions that rely on MVHR distributing heat from one room throughout the rest of the house. It does work to an extent (we used a 1.5kW column heater in the kitchen to warm our entire house last winter), but switching on aircon heating for an hour in one room will have little impact on the temperature in the rest of the house. In my opinion, if you're going to have MVHR anyway, you're better off looking for a solution that introduces some heat into the MVHR supply. Low level heat to all rooms will work a lot better than having one room being blasted, imo. There are all sorts of options for this. If I were doing it again, I'd stick with UFH driven by an ASHP, but add a loop to allow some comfort heating of the MVHR supply air (really just enough to take the chill off the air due to the imperfect heat exchange in the MVHR unit).

Right, didn't pick that up until now. What a pain

I don't quite follow everything that's been going on, but why did you get what you wanted last time but not this? Surely that's the crux of the matter...?

We have exactly the same arrangement (except no heating in the bathrooms!) and exactly the same problem. It's always cooler in the bedrooms than it is downstairs. Presently the bedrooms are about 19 degrees, but that's with downstairs pumped up to about 22 degrees. I'd be fine with it if the bathrooms were warmer, and indeed we're in the process of retrofitting IR panels to try and address this. I quite like this bedroom temp. My wife would like it warmer, but then I'd die of heatstroke overnight. I balanced mine. The problem (I speculate) is that if you turn up the fan to get more air (and hence more heat) being distributed, you increase the losses due to lower heat exchanger efficiency, so the incoming air ends up being cooled more. Turn it down to increase heat exchanger efficiency and less air is moved around, so you still end up with cooler bedrooms! We have a very wide open staircase, and another double height area of 6m2. While the upstairs landing does warm up to an extent, the heat doesn't work its way into the bedrooms very well. The air delivered into the bedrooms is naturally cooler than the house average temperature due to the heat lost via heat exchange inefficiency. Unlike downstairs where the heat deficit is quickly made up by the UFH, upstairs, the cooled air is delivered directly into unheated bedrooms, then swept out of the bedrooms into an ensuite or the landing for extraction via the bathroom. This airflow prevents much warm air making its way into the bedrooms from the landing. As for how to solve the problem, if there's already wiring in place, one solution would be to have the electrician install power points at these positions. Assuming you have basic handyperson skills, you can then source and install your own heaters, which will be a lot cheaper than what's presently being proposed.

I'd still be unable to find a tape measure by the end of day one.

Why would they subtract the depth of the wallplate though? By definition, the joist ends have to rest on that! Ask them what they think the joists are supposed to rest on if not the wallplates. The fact that they got it right the first time around shows that they've just cocked it up. Can you kick it above the head of whoever you're talking to and get a manager involved?

The agreed drawings also say: Not exactly clear language, but is at least an admission that they were aware of the existence of wallplates.

Yup. What they've supplied isn't consistent with any reasonable interpretation of the drawings (including the interpretation they've tried to squeeze past you).

Even if what they say is true, you'd expect to have been supplied with joists at least as long as the distance between the wall plates, plus some amount for trimming (hence "trimmable"). What's the other end of the joist doing in the first photo? Is it against the far wall or the wall plate? Either way, I can't see that there's a trimmable portion, no matter what they think the measurement should be based on.

And yet they accepted an order from you on this basis, just like last time. They're taking the piss. Does the diagram that was annotated (and agreed) have arrows showing what the dimensions relate to? I'd have thought would be the end of any conversation on this point.

Agreed. The only reason to be doing anything other than demanding the correct joists is if that will delay you and you can come up with an alternative that reduces the delay.

I'm not annoyed - I'm just allocating my time as best I can on a crazy busy day. In all honesty (and in the nicest possible way) I genuinely had the feeling that nothing anyone says will change your mind, so there didn't seem to be much point arguing. My main concern about the island is less the diagonal wall per se, but more how you've aligned the island with it, and defined a large triangular area between the island and the corner of the kitchen up from the fridge. To my mind, that whole area consumes a lot more space than it contributes by way of function. By way of reference, we have 1.2m spacing between our island and the adjacent run of cupboards. That distance is more than enough for people to walk past unimpeded while the dishwasher is being unloaded. Any more and the island would start to feel disconnected to the rest of the kitchen. We figured out this spacing by building a rough version of the island as I explained above. In your case, I suspect the island is so far away that it will feel separate from the kitchen. All that said, I'm just some bloke arguing on the internet. If you rig up some walls and an island with cardboard or whatever you have to hand, there'll be no speculation. You'll either confirm that it's what you want, or you'll avoid a potentially costly error. Either way, it's a win. The comments about awkward spaces included some of the stuff mentioned by others (@the_r_sole in particular), but unfortunately I need to get back to work so can't expand any more at the moment.

Optimist.

Why do you conclude that this decision was about money? We turned off the heating before we went away because our ASHP was on the blink and we didn't to leave a resistive heat source unattended for three weeks in case something went wrong.

And that's exactly why I don't see much point in expanding further on what's really just my personal opinion. Also, several others (including an architect - @the_r_sole) have raised related questions about your choices and you've stood your ground on literally every point. Entirely your prerogative, naturally, but hopefully you can see why I might be reticent to spend much more time on this! All the best.

What will we do/read if we allow him to finish it?

So I'm starting to see the genetic source of the: If an architect used that language, I'd be asking him or her to explain what it actually means. If you can't see from the plan how awkward that diagonal wall and island position are going to be in real life, then all I can suggest is that you get some cardboard and scraps of wood, and build the diagonal walls, island and cabinets (and perhaps even the furniture) in the existing space. I think you may be surprised at how much space is wasted, and how awkward it will feel when you're standing in it. From your responses so far, I doubt anything anyone's going to say will convince you otherwise, so perhaps this is the best way to convince yourself that you're right! I personally don't think your storage spaces are particularly practical - they're too deep for shelves, and not deep enough to allow walk-in access. I don't see how a wall being diagonal makes any difference to storage space. I'm a natural contrarian myself, but unless you've actually lived in a house that has all of these unusual features, I think you're taking a massive risk. To me, both plans are lacking cohesiveness - neither feels like things are where they naturally should be. There are lots of random nooks and corners without any apparent reason for them. You say you like honesty, so here's my last bit of that: I suppose you didn't ask for feedback, but if you've lurked long enough, you'll know that posting a floorplan is going to get you a fair bit of it. Nothing anyone's said seems to have had the slightest impact at all. No need to post an answer, but you might ask yourself what you were hoping to achieve with posting this given that you and your mother appear to have finalised your positions already.

I didn't keep that close an eye on the weather, but I believe it was very cold and windy without much sun while I was away. We're a little light on solar gain due to trees and our window layout, so our house tends to be cooler on average than some other MBC builds (eg, Jeremy needs less heating, but more cooling, than us). Unfortunately my 1-wire system was on the blink during that period so I can't tell exactly what was happening. I can't imagine it would have fallen too much further after 3 weeks with no internal gains at all (other than energy losses from the fridge and minor electrics).

Whose side are you on?

At least in the right hand barn, the cleaning would be exactly the same, since you're just converting a bathroom to an ensuite. I also can't see why anyone would be walking through the bedroom to use that ensuite given there's a bathroom right next door. I've lived in something like 20 houses as an adult, in three different countries. Only two had ensuites, and I would never go back to not having one if I had the choice. I can't recall ever meeting anyone who wasn't a fan of ensuites, so I think the interest in them goes a little beyond "lots of people". You say you've designed this to suit your lifestyle, but there are two barns. Are the two families that are going to live in them both committed to not having ensuites? No offence, but being against ensuites is a pretty idiosyncratic position for most people. But hey, it's your money, and your house. Re: the right hand barn, the position of the island seems to introduce a large triangular dead area between it and the rest of the kitchen. For me, that would be impractical and feel strange. When we were laying out our kitchen, I knocked together some rough frames out of scrap timber and clad it with some leftover sheet plastic. It gave a great idea of what the actual space would feel like, and led to us to tweak the dimensions and position of the island to better use the space. Can you do something like that? I personally think you'd have more efficient use of space if you didn't have all the angles in the kitchen. Has an architect been involved with this? I know a lot of people don't want to pay for them ("I know what I want!"), but this seems like exactly the sort of project to which a good architect could add some serious value. By "value", I mean lifestyle quality rather than just making the final building worth more financially (although I suspect they'd achieve that too). It does look like an exciting project. Do you have any pics of the barn you'd be willing to share?

It was a lifesaver during the extended heatwave we had this summer.