Carpet in the bedroom despite underfloor heating?

With today's underfloor heating with low temperature, you don't feel the warmth, you just HAVE it. In today's houses, all temperatures flow into each other: if you have 22 degrees in the living room, you won't have 18 next to it.

We are also interested in carpet for several rooms. One often reads that carpet should not exceed a thermal resistance value of 0.15. Ours would be an expensive branded product, somewhat high-pile, suitable for underfloor heating, but with a value of 0.17.

Can you still use it without concern or is it better not to? Is there any way to express or calculate the difference between 0.15 and 0.17? What values do your carpets have? And do you feel higher energy consumption because of the carpet?

I believe the idea is that higher values are better than lower ones... at least when you are talking about the U-value. Compared to tiles, you have about 13% less heat transfer.

The bigger, the worse. Quote:

The most important criterion is the thermal resistance. This results from the ratio of thickness to thermal conductivity of a floor covering: The higher the thermal resistance, the less the underfloor heating can deliver. For this reason, the thermal resistance for the floor covering on an underfloor heating system should be a maximum of 0.15 m² K/W.

And now the question arises as to why exactly 0.15 m² and how bad is 0.17 there? Still within limits or already completely in the red zone. I would like to somehow estimate what extra consumption this causes, because 2 decimal places initially seem small.

We are also interested in carpet in multiple rooms. You keep reading that carpet should not exceed a thermal resistance value of 0.15. Ours would be an expensive branded product, somewhat high-pile, suitable for underfloor heating, but with a value of 0.17.

Can you still buy it without worries or better not? Is there any way to express or calculate the difference between 0.15 and 0.17? What values do your carpets have? And do you feel you have high energy consumption because of the carpet?

The thermal resistance applies to all floor coverings, so also to all layers: surface material, backing, adhesive, and possibly insulation material.

Your preferred carpet is approved for underfloor heating, even though it exceeds the value of 0.15?

You write high-pile... logically, the green lights in thinking heads should fade and turn yellow.
What kind of backing layer is it???
For carpet, the material as well as the density and length of the surface material, as well as the composition of the backing and adhesive, play a role.
So if foam is added to the high-pile, we would be in the red zone – but I would always want to stay in the green zone.

Dach you mean the lambda value with your 0.17 .. my bad. Assuming your carpet is 1.5 cm thick, you get a lambda of 0.09 W/mK and accordingly an R-value of 0.17. This means about 35% worse permeability (if you assume 12 cm insulation under the screed) compared to tile. They just have to be compensated by higher flow temperatures.