KFW70 with gas-solar heating

Why insulation instead of a thicker Poroton brick?

An architect I spoke to recently said that this is the best way. Because the reinforced concrete ceiling still settles slightly, the bricks develop cracks. If they only have a plaster layer, these cracks can also be seen on the plaster facade. If there is insulation on top, the cracks in the bricks are not visible.

No idea if this makes sense or if it is like that, but the construction company is building it for us this way.

Cracks in the stones?! And that is then sold to you as the state of the art?! I don't know, but I would definitely ask critical questions more than once...

If you choose aerated concrete as the stone, you can also consistently do the 365 mm.
I believe many providers sell, in addition to the material, also partially the good feeling of KFW.
The surcharge for a bit of insulation is never, ever 7 thousand euros – unless the type of wall changes.
Triple glazed can mean a whole lot and I find that indication to be unprofessional (unless you simultaneously have the energy saving ordinance calculation on hand – it states exactly what you get)...
For example: triple glazed can mean that you have a Uf of 1.3 and a Ug of 0.7 or a Uf of 0.78 and a Ug of 0.5.
For a normal double window 1.76 * 1.34 with a 5 cm frame, that results in: 2.18 m² glass and 0.58 m² frame. That means either a heat loss power of 73 W (at -12° outside temperature and 20° inside temperature) or one of 49 W... so a difference of about 30%. If you consider that KFW70 in terms of primary energy demand only means that you are 30% below the limit, that’s already interesting.

I find the statement about the cracks in the stones more than strange. What about the interior plaster then? It would have to crack even more because it is applied much thinner and without a base coat onto the stones. I believe the company simply builds differently and sells this under this rather odd-sounding argument.

We are building a timber frame house. Insulation will be done with cellulose. According to the architect/energy consultant, we will easily achieve KfW55 with it, and it will be quite "bio" thanks to renewable raw materials as well.

A brick-on-brick house builder we visited had already rolled his eyes when we mentioned KfW70. With wooden houses, good insulation might actually be easier to achieve.

It is just as feasible with a 49er Poroton, even without 7-fold additional claddings + 7 x extra work, ventilations, and OSB boards-, spruce boards-, plasterboard madness at cubic meter prices beyond good and evil > 700 euros + upwards.

Put a mineral plaster on the outside of the 49er plan brick, a clay plaster on the inside, and add decent window material with Uf 0.78 + Ug 0.5 values, and you almost have passive house standard.

The cubic meter stone costs about 80 euros material price, including adhesive, exterior plaster, and interior clay plaster.
The wooden construction is 4 times more expensive than a brick construction and only offers approximately the same values.

A brick house is biological enough ....?