-rick-

This is bollocks. Here are some cold hard numbers. Maximum possible humidity is 100%. Assume your outside air is saturated (100% humidity). Assume its 10C outside. If you heat your indoor space to 20C the air, holding exactly the same amount of moisture will be at 50% humidity, which is perfectly fine for an indoor climate. No dehumidifiers needed, just heating the house to 20C vs the outside air of 10C. If the outside air is 0C then you only need to heat to 10C to get the humidity down to 50%. This all assumes you aren't introducing more humidity into the air (which of course we all do as living beings) but the point stands. To solve humidity issues in a house, warm it up.

One of the reasons I have noted for insulating pipes is that the insulation can act as a buffer/decoupler from thermal movement and noise (assuming you strap the insulation not the pipes).

I have no confidence we can get your place warm during the day if you let it cool down like this overnight. Frankly I think it's a waste of time to try and help if you are not willing to consider higher. It might be possible that this will work during the shoulder months (ie, now) but it won't work during the winter. If you want to have 10C overnight then you would need to accept that the temp during the day won't be much higher. If your concern is noise, then that can be dealt with separately. With my bedroom door closed I can't hear my boiler running 2 meters away, I'm sure it's possible to arrange that for you as well. Even maintaining 10C overnight when its 0C outside will involve the heatpump working overnight. So setting 10C isn't a way of limiting noise. It's just a way of never being warm.

That would be an excellent result. When I've done rough calcs to see if his heatpump could cope I've used a U value of 2 (1.71 was the worst case wall looked at in the Scottish study I used and I rounded up to be conservative). Even with a U value of 2 the heatpump should be capable (barely) of maintaining the space at a steady temp.

I'm not sure your experience can apply to Zoot too well. He has a 9kw heatpump that will work most efficiently with relatively cool radiators. A 30kw AGA pumping out heat to the radiators at 70C will have a much easier time heating the air quickly for short bursts than Zoots heatpump. On the coldest days zoots heatpump might have to be working near flat out just to offset losses meaning no spare capacity to alter room temp. I very much hope that zoots property has better heat loss numbers than these worst case calcs suggest but without a more detailled information from zoot it's the best we've got.

Oh boy. Lots going on while I was away, not sure where to start. @zoothorn I'm glad you will considering moving the controller even temporarily. I know it sounds crazy to you but I think it's quite important for the thermostat to be in that cold room. It's possible this may lead to other rooms being hotter than you want but we can deal with this in other ways. We've gone round in circles about how you think your place is uniquely cold including statements like the above. It just doesn't stand up. I've checked, Slate has a higher ability to store heat than sandstone (they are pretty close). Earth is even better. You have a misunderstanding of how this works. It's a common misunderstanding but I feel that you've struggled with your house so long it's become almost a religious belief and you just can't believe it when people say you've misunderstood. I will try again below but even if you don't believe it then please don't let that belief stop you trying something different. People coming to your house express how cold it is because you've let the building go cold. Your very thick walls are very big energy stores and the temperature of them will change slowly not fast. When you put heat into the room, you heat the air first, but the walls stay cold. It takes the room being warm continiously for a long period of time for the heat in the air to slowly transfer into to the stone. If you turn the heat off then the cold in the stone quickly cools the air making you feel as if the place is just always cold. My whole goal of this conversation is to get you to try to warm the stone walls up. This will take a lot of time and energy, but once the stone is warm then the amount of energy use to maintain that state should be similar to the other uninsulated homes we've already discussed (more than you are paying now for sure). Once the stone is warm you will find that turning the heating off for a short period doesn't lead to the room quickly getting cold (if it does you have bad drafts that need fixing).

Ideally UVC should be optimally placed for short pipe runs to the bathrooms/kitchen. Wherever that is (up or downstairs doesn't matter). I'm sure others will disagree with me but UFH manifold should be central and if that's not where the plant room is so be it. Can be built into a cupboard/bump-out/etc. Does need to be accessible but can be remote from other plant (unless you want to do lots of zoning or other complexity which this forum advocates against).

Yeh it's not perfect but my thought was not to steal space from the room, just reorient the space. I'm not doing this with a ruler so very handwavy. There is likely room to optimise space use between the two bathrooms if they back onto each other, etc.

The cupboards are on your plan to the right which might make this area pretty awkward. Personally I would go for larger doors if you want to market the property. Some people would be put off by small seeming ones.

Along these lines. Putting the stairs on the other side of the corridor might open up some flexibility as well. Edit: Personally, I'm quite keen on clustering bathrooms for ease of service routing, but even if that isn't a concern an arrangement similar to this provides the master with a buffer from noises from the shared bathroom and removes all bathroom noise from the bedroom adjoining the master. Btw, it's not entirely clear which room is which, the measurements didn't make sense to me.

Some initial thoughts: 1. I don't like the blue area. Was thinking you could move the bathroom over a bit to avoid it but then realised you might have regs problems with the door directly at the top of the stairs. Not actually sure pushing the door back as you've done is good enough for regs. 2. Doors to the bathrooms seem awkward, especially the en-suite. Guess a pocket door makes it work but maybe better layout options available. 3. Feel like there might be some better layout options overall but still thinking.

Yes, your bills will be higher than in a well insulated house. That's a fact. But as Nick, my mum and many others can prove uninsulated houses can be heated. Right now you don't think your house is capable of being heated and I think it's important to firstly prove this wrong. Then once your house is up to temp you can work out what the bills would be do keep it warm. Once you know what it costs to heat you can work out whether it will cost less money to make improvements to lower bills vs just paying higher bills. You could do this, but it's going to create a huge mess, cost a lot of money and quite possibly not save any money on running costs (make you feel warm). Better to prove the house can be heated first. My guess is that the most cost effective improvements are in the upstairs rooms, but only if you run the house with minimal setback. With 2ft thick walls if you let the house go cold it will take ages and a lot of energy to warm back up again. I think you might be getting things mixed up here. As long as you keep the upstairs at approximately the same temp as downstairs you don't need insulation in the floor. The earlier discussion was about stopping loft air getting behind the plasterboard. I did mention the possibility of putting fluffy insulation in the floor void if it was accessible but it wasn't the main point. Why do you say this? A setback is very standard. But it should only be a few degrees. The bigger the difference between daytime and nighttime the less effective the heating system will be.

Please pause for a minute and reconsider this. I'm not convinced your system will work well if you set such a low set back. If you want your bedroom to be cold at night thats fine, but the rest of the house needs to be kept warmer. Try to think about your bedroom seperately from the rest of the house. You can turn the radiator off in your bedroom before you go to sleep and turn it back on in the morning. At least to start with. If that works out we can improve things. As to noise, now that you have replaced the previous system you shouldn't really be hearing any noise inside when the system is on. Do you? If the room it's in is cold then it's better than I thought when it sounded like it was inside the cupboard with a cylinder. However, it's still not great. As your house warms up the upstairs will inevitably warm first. Yes you could set the thermostat to say 20 with the aim of getting the downstairs to 18 but I suspect given your thick walls that still won't work well. You've said you don't want the controller in the sitting room. Why not? it sounds like the perfect place for it? If you don't like the screen being on then I suspect theres a way to turn it off when you aren't pressing buttons. If you don't like the way it looks there's likely a way to disguise it (though it needs good airflow around it).

Ah sorry, that may have lead to some confusing conversation then. Good, There's too many things going on here. To repeat my view, lets keep things as simple as possible until you have the temperature of your place under control. After that we can tune things if needed.

Would have thought that would depend on both what you put in it and also what type of machine it is. ie, does it vent air to the room or not. AFAIK heatpump dryers don't cycle the air in the drum outside the machine. If the clothes are cotton, I'm not sure where the plastic comes from. If you wash a lot of nylon/polyester then sure.