30cm thick exterior wall - Energy Saving Ordinance 2014 compliant?

Poroton T8 is available from Wienerberger in a thickness of 30 cm. This achieves a U-value of 0.26 and just stays below the requirement of 0.28. Whether there is a static problem - no idea.

That is not sensible. Why not at least 36.5 or 42.5 in monolithic masonry?

According to the following information page, the limit for the Energy Saving Ordinance external walls is 0.24, so what is the limit now? I am a bit confused

link removed by moderation; construction expert

Also, this is the first time I’ve heard that better window and roof insulation allows for a worse U-value for walls. (That would be great)

36.5 cm would also be possible, but for planning/dimensions/size, 30 cm, if possible, would be better.

PS: By 30 cm I mean purely the brick (without plaster etc.)

Then reinforced concrete with ETICS...

Your link is for existing buildings/renovation. That shows you how pointless the idea is. Your house would be worse than a newly renovated old building.

Why would 30 cm be better for planning? Doesn't your planner have a thicker pen?

If the property is only 11 m, it already makes a difference whether you have 13 cm more or less available... that would be my guess.

30 cm aerated concrete should be sufficient.

Right, PP 1.6-0.25 with Lambda 0.07 is also available in 30cm. That just reaches 0.22 as the U-value at 30cm plus plaster. But then it will be very expensive, I think.