Is Ytong 30cm still somewhat useful?

Good morning,

We have now received a generally quite good offer from a company, which, to our surprise, builds with a 30 cm Ytong block.

So is "only" the price at the bottom right tempting?

All other providers we have dealt with so far use a 36.5 cm Ytong block.

36.5 for good reason; although almost any other unfilled 36.5 block can be used.

The Energy Saving Ordinance will probably be met with this house, but I actually don’t feel very comfortable about it.

The Energy Saving Ordinance is not fulfilled solely by the chosen block but - with the right combination - it is achievable with almost any block. The question is, which KFW standard you want to achieve and which funding sources you want to tap into?

We plan an air heat pump and a ventilation system (which is a requirement), and I have some concerns that the energy I can save with it will be lost again through the thin walls.

But you’re not hoping to save heating energy costs with a controlled ventilation system, are you?

I would recommend that you read more on the forum, then you will understand €uro’s comments better and many of your questions will also be answered through other users’ threads.

Best regards from the Rhineland

For me, it is purely about the thermal insulation of the exterior wall; that there are other factors is completely clear to me. I thought that was evident from my post. It is a very reputable provider, which is supported by several points so far. For me, it is purely about the U-value. It will hardly fail because of €450, but it would be interesting to know to what extent a U-value of 0.02 actually pays off. The Energy Saving Ordinance certainly takes several factors into account, but the exterior wall must also be appropriate, and I was somewhat shocked that this is being maintained because most now offer far better exterior walls as standard. Ventilation and exhaust are mandatory as described. We do not want to use KfW. PS: The search function does not allow such short queries.

For me, it’s purely about the thermal protection of the exterior wall; I am fully aware that there are other factors....

Additional thermal insulation reduces heating energydemand in any case!

However, the actual or expected consumption largely results from the efficiency of the system technology.
As an expert, I also deal a lot with renovation projects where the expected savings through insulation were often only partially or fragmentarily fulfilled. Therefore, investors are sometimes severely disappointed!
Often, this is not due to insufficient insulating performance of the building material! The main reason is usually that the system technology is completely out of focus! Sustainable insulation measures generally require more or less significant system-side adjustments! This is concealed by insulation material sellers or is entirely unknown to them due to a lack of professional training!
Even in new construction, you cannot do without proper planning and dimensioning of the system technology!

Those who want to gain/receive x € must first invest a few €! Nothing comes from nothing after all!

Best regards