Poroton T12 stones exterior wall

I had actually had the unfilled Unipor W08 plan bricks included in the construction service description. The W08 Coriso costs about 40% less in the price list than the plan brick in 36.5 cm. I actually didn’t want filled stones, but now I’m really starting to doubt... Maybe larger buyers get completely different prices, and then in the special case the plan brick is still cheaper than the filled one? Very non-transparent.

I would guess that because of the larger chambers, less tone, and more wool, these are cheaper.

We have currently only completed the base slab (with 6cm insulation on the underside). Masonry work is planned for January (Plan T12 Poroton). I inquired about the thermal insulation certificate before Christmas, and I was informed that it will be handed over to us after completion. Is this "correct"? Shouldn't the energy saving regulation calculation already be available beforehand? In any case, we were always told regarding change requests: changes are possible as long as they do not "alter" the structural stability or the energy saving regulation. The building application has already been submitted and building approval (green dot in BW) has been granted.

Is there a chance that (if the T12 bricks have not yet been ordered) it could be upgraded to a higher-quality stone, as the manufacturers are phasing out these "old stones" to promote newer stones? Are there any experiences regarding whether GUs are "open" to this?

Questions cost nothing... How are the remaining exterior surfaces of the house designed? Insulation below/above the floor slab? Insulation of the top floor ceiling or roof insulation? U-value of the windows?

Questions cost nothing... How are the remaining exterior surfaces of the house designed? Insulation below/above the floor slab? Insulation of the top floor ceiling or roof insulation? U-value of the windows?

We are building according to the Energy Saving Ordinance 2016.
Bottom of the floor slab: 6cm insulation.
Above the floor slab: 7cm insulation
Perimeter insulation: 6cm

Masonry 36.5cm T12 Poroton.
Windows: Ug 0.70 W/m2K
Insulation of the top floor ceiling: mineral wool insulation WLG 035 200mm

Sounds more or less like quite normal new build standard, except for the masonry. Just ask about the price difference for better insulating masonry, maybe the general contractor doesn't even charge exorbitant prices. You won't achieve utopian energy savings by improving the U-value from 0.3 to, say, 0.22 anyway, but in your place, I'd consider the few euros extra worth it. Are you heating with a heat pump or with gas? Paying attention to good design of the underfloor heating and setting of the heating system can potentially save as much on energy costs as better U-values of the building envelope.