Thermal curtains - do they work - who has experience?

Please try not to intentionally misunderstand my posts. When I say "the circuit is closed," I am well aware of the fact that the screed still releases its residual energy for a long time.

My point is that with ERR I am able to "switch off" a room for an extended period. In this case, the heating curve and the balancing no longer matter.

You can also simply turn off the heating circuit without ERR. The hydraulic balancing will be messed up anyway... If you change something in a system with, for example, 20 heating circuits at 3, the system will logically no longer be in an optimal state afterward.

In your example: The upper rooms are heated along even though less heating surface is available. That means you need a higher flow temperature than if all heating circuits are open -> efficiency loss.

Who actually says that you can achieve more or less temperature difference in the rooms with ERR? I don't have ERR, but of course a warmer bathroom than bedroom (of course limited). That’s how my system is set up... ERR only makes sense if you have a heating system that can quickly change temperatures, i.e., when you have radiators and a heating system with a high flow temperature.

Who actually says that with ERR you get more or less temperature difference between the rooms?

I am such a representative because there is still a certain difference between "a little heating" (via hydr. balancing) and "no heating at all" (via ERR off). In the short term, in the sense of hours, it doesn't really bring much, but over days it certainly does.

Let me elaborate further. As you know, the difference between control and regulation is that regulation responds to external disturbances. In this sense, the factually fixed setting you apply to the hydraulics is a control, but the ERR is a regulation. That’s the theory, now to my practical problem:

At first, I also deactivated my ERR and temperature-differentiated my rooms via hydr. balancing. However, I have a 15-meter-long facade that is oriented exactly to the south, and accordingly one that is oriented exactly to the north. In winter, I have enough heating power from solar gains on the south side to exceed the desired room temperature quickly. That is the external disturbance to which the ERR can respond. If I rely only on the hydr. balancing, heating continues nonetheless, because the outside temperature sets a corresponding flow temperature, which may also be necessary for the north side. If I use ERR additionally, a total of 7 to 8 heating circuits are switched off with me, even for days during sunny winter weather. Here we are again at the meaning and purpose of a regulation.

If you change something in a system of, for example, 20 heating circuits at 3, the system is logically no longer in its optimal state afterwards.

That is not true if by "system" you refer to the hydraulics. The hydraulic balancing is not disturbed when using a Delta-P circulation pump. I think today all circulation pumps have Delta-P regulation.

Of course, I have also carried out hydraulic balancing and optimized my flow temperature, only my settings perhaps run "a bit richer". I have a flow temperature about 3 Kelvin higher than "necessary" so that I always have nice warm feet in the bathroom while the window is open. If energy prices are no longer as low as today, I’ll turn it back by 3 Kelvin – but I still need ERR on the south side in sunlight.

However, I have a 15-meter-long facade that is oriented exactly to the south, and accordingly one that is oriented exactly to the north. In winter, I have enough heating power quickly through solar gains on the south side to exceed the desired room temperature. This is the external disturbance factor to which the ERR can respond. If I rely only on the hydraulic balancing, heating will continue anyway, because the outside temperature dictates a corresponding flow temperature, which may also be necessary for the north side. If I additionally use ERR, a total of 7 to 8 heating circuits are switched off, even for days during sunshine in winter. This brings us back to the purpose and meaning of a control system.

I have a similar "problem". I do not have individual room control, but what I do have is a control unit in the living room (similar to you, huge solar gains through large window fronts). The heating control therefore does not work exclusively based on outside temperature, but is a combination of outside temperature and inside temperature. What is not influenced by this, however, is the hydraulics of the underfloor heating, because individual heating circuits are not adjusted; rather, the heat pump generally supplies less or no energy to the house. The solar gains are distributed more or less throughout the whole house anyway, at least in well-insulated houses.

Another important point: I have passive cooling via the geothermal heat pump, which automatically activates above a certain temperature threshold. It must be ensured that enough heating circuits are open for this... without ERR, you don’t need control for this, nor can anything go wrong. Especially in rooms with strong solar gains, a little heat is continuously removed here, and the temperature settles a bit lower without significant costs.

Of course, I have also carried out a hydraulic balancing and optimized my flow temperature, only that my settings might run "a bit richer." I have about 3 Kelvin higher flow temperature than "necessary," so that I always have nice warm feet in the bathroom while the window is open If energy prices are no longer as low as they are today, I will reduce the 3 Kelvin – but I still need the ERR on the south side when there is sunlight.

If you don’t care about efficiency and don’t have any expectations of sustainability yourself (no judgment), then you don’t have to deal with optimizing a heating system, let alone thermal curtains. Of course, everyone must handle that as they wish. From a purely financial standpoint, we are not now talking about numbers that would really hurt anyone who can afford a house The time that some (myself included) spend on optimizing the heating can certainly be used in a way that is much more valuable elsewhere... Let’s just call it a hobby

Okay, then you ultimately also have a control system that prevents continued heating when exposed to sunlight - with an additional comfort benefit through possible cooling, I’m almost jealous. Your system in my house would have the disadvantage for me that the heating in the bathroom (north) switches off when it gets too warm in the living room (south). There is no such thing as “too warm” for me in the bathroom.

“My” control system is also efficient to a certain extent - simple switching off under certain conditions is still better than if energy input continues under purely hydraulic balancing control. Nevertheless, I am purely comfort-oriented in this respect, that’s true, but with my energy source (gas combined heat and power unit) I don’t benefit from the lowest possible flow temperature either.

Conclusion: The design or evaluation of heating controls often does not work according to a fixed scheme.