ᐅ Is this masonry construction sufficient for KfW55 standards?

Hello

I know there are different components to achieve KfW55 standards. However, I would be interested to know if this wall construction is at least sufficient for a new build:

• 17.5 cm (7 inches) aerated concrete block
• 14 cm (5.5 inches) mineral wool insulation
• 2 cm (0.8 inches) air gap
• 11.5 cm (4.5 inches) facing brick

a) Ask your energy consultant
b) It doesn’t matter anyway, since KfW 55 is no longer subsidized
c) It doesn’t matter anyway, as you won’t notice any difference inside the house whether it’s KfW 55 or 58

P.S. Why an air cavity? Why not sand-lime brick as the masonry?

Benutzer200 schrieb:

a) Ask your energy consultant
b) It doesn’t really matter since KfW 55 is no longer subsidized anyway
c) It doesn’t really matter because you won’t notice any difference inside the house whether it’s KfW 55 or 58

P.S. Why an air gap? Why not calcium silicate brick as the masonry?

Because that’s what is stated in a quote, and I want to know if it’s a good or bad offer.

MeinHaus45 schrieb:

Because it says so in a quote, and I want to know if it’s a good or bad offer.

Without the price, area, etc., it’s impossible to say whether it’s good or bad—at least financially.
If the financial aspect doesn’t matter, it might be suitable for 55 years. You should really ask a professional, but it was already explained why it’s basically pointless.

We have a similar construction, and next time I would choose sand-lime brick. Houses built with aerated concrete are extremely noisy comparatively.
If you can live with that, then the construction is definitely acceptable.

Benutzer200 schrieb:

Why an air gap?

Because that’s how it’s done?!

Benutzer200 schrieb:

Why not use sand-lime brick as the masonry?

Because it is (slightly) more expensive?

MeinHaus45 schrieb:

• 17.5 cm (7 inches) aerated concrete block
• 14 cm (5.5 inches) mineral wool insulation
• 2 cm (0.8 inches) air gap
• 11.5 cm (4.5 inches) facing bricks

We built it almost exactly like that and achieved KFW55 standard.
However, instead of the 14 cm (5.5 inches) mineral wool, we used:

14 cm (5.5 inches) hydrophobic (water-repellent) core insulation boards KDII with staggered joints, thermal conductivity WLG 035, wall ties made of V4A stainless steel, 2 cm (0.8 inches) air gap.

And facing bricks in NF format.