KFW 70 vs. KFW 55: Advantages and Disadvantages?

Hello,
I have a question for you. We want to build a house, and the company guarantees that it will be a KfW 70 house; the company is now checking whether it can be a KfW 55 house. What are the advantages of a KfW 55 house compared to a KfW 70 house? The financial aspect is also quite interesting to know.
For us, it is clear that we will not put additional money into the house to make it KfW 55. If it achieves this right away, why not. It should also look very good that it manages to be KfW 55.

Hello,

…We want to build a house and the company guarantees that it will be a KFW 70 house; the company is now checking if it will be a KFW 55 house. What are the advantages of a KFW 55 house compared to a KFW 70 house? The financial aspect is also quite interesting to know. For us, it is clear that we will not put any additional money into the house to make it KFW 55. If it achieves this right away, why not. It should also look very good that it really manages to be KFW 55.

A KfW 70 efficiency house requires 70 kWh/sqm, a KfW 55 efficiency house 55 kWh/sqm, and a passive house 15 kWh per square meter per year of final energy. All levels have in common that both the building envelope and the technology need to be adjusted. Meaning – for KfW 70, comparatively less (more cost-effective) and for KfW 55 more (correspondingly more expensive) technology must be installed in the house, aside from the fact that the building envelope must meet the values according to the Energy Saving Ordinance.

What building material will your house be constructed with, what U-value does the building envelope achieve, and what technology will be installed?

Kind regards

Hello, an air-water heat pump with controlled ventilation is being installed. The exterior wall has a U-value of 0.147, the floor slab of 0.205. We were told that this still needs to be checked precisely, but it will probably be KFW 55.

Hello swix112

Let the company do the calculations... whether they could actually achieve a KfW55 house... it is not as simple as it looks at first glance.
In the past, the KfW type designations referred to the consumption per m², but currently the number types refer to the reduced value compared to the reference house! This means that with KfW 70, a saving of 30% compared to the reference house must be achieved in order to receive the KfW bank subsidy. For KfW 55, this would correspond to a saving of 45%... this can really only be demonstrated with individual verification... no one can claim this flatly without knowing the building structure and the technology. And without additional costs (which you do not want), this, in my opinion, will not be possible either.

Yay, it works, today the notification came that it will be a KFW 55 house ......

Hello,

Yay, it works, today the notification came that it will be a KFW 55 house ......

Then let's hope that everything is correct and not "beautified."

Best regards