Solid wood parquet on underfloor heating

In order to compensate for heat transfer/loss to the outside, heat must be supplied via the heating system. If, due to insulation through impact sound insulation, air layers (and the parquet itself, which has high insulation), the heat from the heating is transferred to the room more "poorly" or "slowly," the supply temperature must be higher. As a result, the system is not only slower but also consumes more energy!

Hmm, that does not correspond to my understanding of the thermal relationships, but I could be wrong. As I said, with a constant indoor temperature maintained, in my opinion, this should not matter. It’s like a pot with holes in which you want to maintain a certain water level. Whether you put a glass in it or not makes no difference to the total inflow you need, once the glass in the pot is already overflowing. Yes, it takes longer to reach the desired level from zero, but if you then change neither the inflow (into the glass) nor the holes in the pot, the inflow can remain the same. Sure, the weather makes the holes bigger or smaller, but accordingly a modern heating system would adjust the inflow. The glass always stays the same size, and the desired level should also always stay the same. You only get problems if someone wants more or less water in the pot for a short time.

Hmm, that does not correspond to my idea of the thermal relationships, but I could be wrong.

Where is the mistake in my description?

As I said, with a constant indoor temperature maintained, that should not matter in my opinion. It’s like a pot with holes where you want to maintain a certain water level. Whether you put a glass in it or not makes no difference to the total inflow you need if the glass in the pot is already overflowing. Yes, it takes longer to reach the desired level from zero, but if you don’t change the inflow (into the glass) or the holes in the pot afterwards, the inflow can stay the same. Of course, the weather makes the holes bigger or smaller, but correspondingly a modern heating system would adjust the inflow. The glass always stays the same size, and the desired level should also always remain the same. You only get problems if someone wants more or less water in the pot for a short time.

With such comparisons, it makes sense to also describe what each part corresponds to in the real world. So what is the water, the pot, the glass, etc. Especially the glass I find very unclear.

Even though it’s not quite easy for me, I will try to stick to your example: Water is heat, the pot the house, holes in it the losses to the outside.

Here it is now so that depending on the holes I have to regulate the inflow to maintain a constant level (temperature). Let’s imagine that as a hose. A flooring with low heat transfer (glued parquet, floating parquet, carpet, ...) is a narrow hose, a flooring with high heat transfer (tiles, vinyl, ...) is a thick hose. Now the pump has to generate a higher pressure for the narrow hose than for the thick hose to get the same amount of water into the pot. In reality, that is then the warmer supply temperature and the higher energy consumption.

In general, inertia, slowness, etc. seem to be confused. Because if something takes longer to transfer energy, i.e. more time (h) for the same energy (kWh). And that means the power (kW) decreases.

To increase the power again so that it does not get colder in the house, the supply temperature must be raised.

Thank you for trying to stay on the same page.
The glass was an additional air layer for me. In my understanding, once the glass is full, it is essentially irrelevant whether it is there or not afterwards.
In your picture, screw it, whether the hose is thinner, as long as my pot can maintain the required level.
You assume that just to maintain the level, a higher total flow rate is needed than the thinner hose is capable of delivering at the same volume of water.
I believe that can only happen if the holes in the pot (i.e., the heat loss of the house) are larger than the maximum output of the hose at the same pressure. Or speaking in reality, the heat transfer coefficient of the thin air layer between the parquet and the heated screed must be lower than that of the exterior shell of the house. I consider that unlikely.
But it might also be that I am completely wrong, I dropped physics relatively early and as far as I remember, we never had thermodynamics.
The thing about the performance kind of makes sense, the only question is whether that still applies when the air layer under the parquet has already reached the supply temperature.

The glass was for me the additional layer of air.

So for you, it is then a kind of storage? However, the insulating floor covering does not act as a storage but rather as an insulator. Storage in terms of heat is usually masses (steel, concrete, stone, ...). These are exactly the things that cause inertia. Insulators, however, prevent heat transfer. So for example 30 degrees supply temperature -> 21 degrees room temperature. Delta of 9 degrees. With a good insulator I need e.g. 33 degrees, thus a delta of 12 degrees. And that does not decrease over time.

You assume that already to maintain the level, a higher total flow is required than the thinner hose can provide at the same amount of water. I think that works

The example with hoses etc. seems not well chosen, because misunderstandings also exist here. I assume that water flows out through holes. This must be replenished through the hose. If I want to keep the flow constant, with a thinner hose the flow velocity must be increased.

the question is only whether this is still the case when the air layer under the parquet has already reached the supply temperature.

That will never happen during heating, because e.g. supply 30 degrees, air layer 25 degrees, room temperature 20 degrees.

So for you, it's a kind of storage then?

More as a side effect and so small that it would be a poor storage if you used it for that.

But the insulating flooring does not act as storage but rather as an insulator.

Insulators prevent heat transfer. So e.g. 30 degrees supply -> 21 degrees room temperature.
Delta of 9 degrees. With a good insulator I would need e.g. 33 degrees, thus a delta of 12 degrees.
And this does not decrease over time.

So you mean that with a fixed supply and a fixed outside temperature the indoor temperature with an air layer will always be lower than without, no matter how long you wait?
Where does the energy go then?

The example with hoses and co. does not seem well chosen because misunderstandings also exist here.
I assume that water flows out through holes. This must flow through the hose.
If I want to keep the flow constant, the flow velocity must be increased with a thinner hose.

But we don’t want to keep the flow constant, rather the level. My thesis is that although you initially have to increase the flow, after that it does not matter how much water comes out of the hoses as long as it is exactly as much as flows out of the holes. And that is exactly the same amount of water (heat) as before. Maybe the picture doesn’t fit; perhaps you have another that analogizes reality better?

That will never happen while heating, because e.g. supply 30 degrees, air layer 25 degrees, room temperature 20 degrees.

And you mean without an air layer the room temperature could then be e.g. 22 degrees or the supply 28 degrees?
Then my question would be again, where does the heat (in the picture the water) disappear to?

The examples are a bit too complicated for me (not: they are too complicated, but for me they are ...)

Heat does not dissolve (as it might seem), but it moves to where an equilibrium is possible.
For example, in winter, from the warm interior to outside, where it is cold.

If it sits in the warm heating pipe, it wants to go to the cold room.
If it sits in the room, it wants to go outside, into the snow.

Where there is insulation, it moves slowly; where there is a good heat conductor, faster.

The faster it slips out of the room through the house wall, the faster you have to heat so that it doesn't get colder inside.
If it slips out of the heating pipe into the room as fast (or faster) as it moves from the room outside, everything should actually be "fine."

Right?