ᐅ Does an aerated concrete block (36.5 cm) require additional insulation?

We want to build a two-story single-family house. Our architect suggested using 24 cm (9.5 inches) aerated concrete blocks, which he plans to insulate with 10 cm (4 inches) of polystyrene and apply a standard render. We would prefer to have the render applied directly onto the masonry, but we are unsure whether, for example, a 36.5 cm (14.5 inches) aerated concrete block alone is sufficient to meet the energy-saving regulations. Would this provide the same insulation performance as the 24 cm (9.5 inches) block with polystyrene?

Hello Camper,
it is certainly possible to meet all energy-saving regulation requirements using aerated concrete blocks without additional insulation. In my opinion, it would be redundant to further insulate a highly insulating (but poorly soundproofing) thin aerated concrete block.

Aerated concrete and cellular concrete are the same; the blocks are white and have a porous surface all around.
Porous clay blocks (known under the brand name "Poroton") are red with relatively smooth visible surfaces and feature vertical hollow chambers.
Aerated concrete and porous clay blocks are often confused, so here is a final clarification.

This aerated concrete is sufficient, and additional insulation is not necessary. It already provides good thermal insulation. What is moderate, however, is the sound insulation.

Aerated concrete masonry provides good insulation starting from the very first centimeter. It has excellent thermal properties. The downside is poor sound insulation. However, this must be evaluated individually for each building project.

Definitely no insulation needed with aerated concrete blocks. However, I am also satisfied with the soundproofing and have nothing negative to report. I always enjoy building with these blocks.

With aerated concrete blocks, the insulation is integrated into the block itself. This results in fewer occurrences of the dew point being reached behind the plaster. However, it is also important to install a ventilation system for the living spaces. Everything must be well monitored to prevent mold growth.

That is definitely a good approach.