Y-Tong vs Concrete without extra insulation in practice (heating costs)

Wall can breathe

I was just very quiet and tried to hear the wall breathe. Didn't work. Conclusion: Walls do not breathe

With concrete it would stay cooler inside in summer

... but only until the heat has found its way into the house once. After that, you can't get it out anymore – like in any other house. The walls just store heat.

That's why Ytong was recommended to us

Did anyone also tell you about disadvantages? For example, in terms of soundproofing? Conclusion is that you can build a proper house with all types of bricks. That even works without bricks (e.g., timber frame). Everything has its pros and cons, but it works. BUT: Concrete for house construction is an absolute rarity. Thermal insulation must then be applied on the outside. Concrete walls also have other disadvantages.

where you can still build concrete without extra insulation; except in bunker construction.

Even here you can no longer do without insulation.

Seriously, pure concrete doesn't work, you might as well camp outside in winter. Or in summer without any shade in the sun.

Just sat very quietly and tried to hear the wall breathe. Didn't work. Conclusion: walls don't breathe

That’s what diffusion-open means. And yes, I know about sound insulation and everything else. For example, that the windows let through more sound than Ytong. I have at least been in such houses and I know that the sound insulation to the outside is completely sufficient. I was actually only interested in a practical example of a pure concrete bunker to find out about heating costs and living climate, to get real data out of pure interest and not the whole theory where every manufacturer, expert, salesperson, etc. say different things and really believe only their opinion is the only true one and everyone else has no clue. I know such buildings exist. Although of course I don’t know if there might be insulation on the inside here. Therefore, I’d like to know why it was built that way. The builder must have had some reason. Because building like that is totally crazy in theory... but in practice?

Or are the exposed concrete houses perhaps made of lightweight concrete?

This resulted in a dense-textured lightweight insulating concrete (LC 12/13) with a dry bulk density of 1,100 kg/m3, which was executed as exposed concrete.
Expanded clay was used as the aggregate, which makes additional thermal insulation unnecessary for the single-layer 50 cm thick wall.

So even with lightweight concrete without ETICS, one works with wall thicknesses that are very special.

Furthermore, 1100 lightweight concrete has a lambda of 0.40; Ytong, on the other hand, is available with values from 0.07 to 0.10.

These are worlds apart.

So I would like to know why it was built that way. There had to be some reason for this builder. Because building like that is totally crazy in theory... but in practice?

1. In practice, concrete is not used. These are usually exotic architect houses or apartment buildings made of prefabricated walls + insulation on the outside. 2. Since all new buildings today comply with the energy-saving ordinance, the difference in heating consumption for construction costs from €500k is negligible anyway. Whether you consume €20 more or less is not determined by the house but by you with your heating and ventilation habits.