The object complies with the KfW standard. What does that mean?

Well, many years ago insulation was not state of the art either. Later, 4cm on the facade became common. Only one thing has been certain so far: energy prices will rise. Most of the costs for insulation are costs anyway. The labor, the work materials, tools... All of this is used anyway. From this point of view, the KfW55 should not cost much more. But it does, because GU and craftsmen include the subsidy for the KfW55 label in their invoice and like to add a lot on top.

From that perspective, the KfW55 shouldn't cost much more.

You are mistaken, it's not just simply 10cm of insulation and that's it. Other factors automatically arise that then increase the construction costs.

And just for example, the 10cm more insulation can mean approximately 2-3sqm more roof area with everything that goes with it, so more wood, foil, roof tiles, gutters, etc.

Correct, at the appropriate points it is indeed that simple. The top floor ceiling does not care how much is placed on it. Also, an insulation below the rafters as an "addition" is inexpensive to implement. Even a slightly better insulation under the screed costs exclusively material. These are decisive factors. And realistically, no one opts for 26cm with a 16cm ETICS, but rather chooses a better material. If built monolithically and additionally ETICS or a better stone is used, the high costs are of course justified. However, possibly a cheaper heating system or similar also comes into play. I find regular surcharges of 15k€ very often simply unjustified.

Eon Ruhrgas has now halved our installment. We started with 100,- per month. They have this kind of forecast calculator. You take a meter reading, enter it there, and bam, now after about 6 months they say 50,- is enough per month. That is the new gas installment. What is KFW 55 supposed to bring then? Our house is energy saving ordinance or kfw 70. We are not freezing. Winter also happened, so, so what!

Well, you have generally been economical in construction and built the house for your golden years.

Most people build for 30-40 years. If, through a small investment, the running costs can be kept low for 40 years, that makes more sense to me than investing in a bathroom fitting for 300€.

Only, as I said, the investment is often unfortunately not small because of the surcharges.

Most people build for 30-40 years.

True, but here I would bet that something significant will change in terms of energy generation within that time frame and that the often heralded fear of massive energy cost increases will not materialize. But yes, it is a bet that one can also lose.

Nevertheless, I am critical of the insulation craze and do not see the point in investing more if the improvements are only in the per mille range. A look at the temperature profile INSIDE the insulation material clearly shows that 90% of the insulation performance occurs in the first 4 cm. My personal opinion is that lobbying here works exceptionally well.

Whether insulation should actually be cheaper than it is offered to me is irrelevant. It IS an additional investment that in my opinion does not pay off. It does not matter to me who benefits from it. I would have to bear it and I am not willing to do so. If insulation for KFW55, 40 or PHI only cost a dime and a penny, we would not have this discussion, because the starting point is that the investment does not pay off. If it were very low, it would pay off again. But that is not the reality.