ᐅ KfW 40 (plus) standard for a multi-family house cannot be achieved

Hello everyone,
I am planning to build a five-family house. Since the plot is very narrow but long, the planned house will be 20.415m (67 feet) long and only 7.24m (24 feet) wide, which are the maximum dimensions approved by the building authority / planning permission.
The house will have two full stories and a 45° pitched roof. The gables will face southwest / northeast. The exterior walls will be a cavity wall construction with a thickness of 49cm (19 inches), consisting of 17.5cm (7 inches) Ytong blocks, 12cm (5 inches) PUR insulation with a 0.24 air gap, and 11.5cm (5 inches) facing brickwork. There will be no basement. All technical specifications meet the requirements of a KfW55-standard house, including a ground-source heat pump, underfloor heating, decentralized ventilation systems, photovoltaic panels with battery storage, etc.
Nevertheless, according to calculations by my energy consultant, the house only reaches KfW55 standard because of the unfavorable length-to-width ratio, and she has reached the limits of her expertise.
Is this a calculation error or is it really not possible?
I am really at my wit’s end...

curverbox schrieb:

All technical specifications comply with the requirements of a KfW55 house,

curverbox schrieb:

However, according to my energy consultant’s calculation, the house only meets the KfW55 standard.

Typo anywhere?

kbt09 schrieb:

Typo somewhere?

According to the thermal bridge analysis, the thermal bridge factor should be 0.00, but the result is only up to 0.03. However, as a layperson, I can’t make much sense of it.

So it depends on the building envelope and not on the primary energy demand or the technical systems?
If the envelope is inadequate, more insulation and/or better windows are needed. It’s actually not that complicated.

The floor plan with only 7.24cm (2.85 inches) thickness is quite interesting, especially combined with 49cm (19.3 inches) thick exterior walls.
It won’t be cheap either with PUR insulation and brick veneer.
An apartment building without a basement? That’s also unusual.

We have windows with a U-value of 0.9 and exterior walls calculated at a U-value of 0.13, yet according to the software, this is insufficient. Even if you make the wall thicker and use a U-value of 0.09, the software still indicates that the targets are not met.

With the building services, we have an overperformance of almost 400%.

0.13 is already really good. It’s hard to improve much beyond that.
What about perimeter insulation and the roof?
Has she ever simulated a basement scenario and adjusted the insulation thicknesses there?
There’s still significant potential for improvement with the windows. 0.9 is more in the range of double glazing.