Planning Single-Family House Construction - Building Energy Act 2023

Hello everyone!

We are currently in the planning phase for a massive single-family house with a living area of 154m² (2 full floors), 77m² of basement usable area, 1010m³ of enclosed space. The start of construction is expected around 08/2023 due to ongoing development measures.

We signed the construction contract (turnkey) in August with the standard according to the Building Energy Act 2020. After the KfW subsidies were put on hold, to be honest, we did not further pursue the issue of energy efficiency with the feeling that we were achieving a sufficiently high standard.
Now, during further planning, we came across the upcoming changes to the Building Energy Act 2023, which, as it reads, have already been decided by the Bundesrat?!

The plan is:
- District heating as an energy source
- Triple-glazed windows (U-value 0.6)
- Exterior walls with 36.5cm brick (0.09W/mK)
- Central residential ventilation with heat recovery including basement
- Basement with 25cm floor slab and 25cm concrete wall thickness + 12cm perimeter insulation (0.035W/mK)
- Roof with 20cm insulation between rafters (0.035W/mK) + 60mm wood fiber insulation as over-rafter insulation

The necessary changes for a "funding-eligible" KfW55 house have currently been priced at about €15,000. I would have preferred to spend that money on a photovoltaic system if it had really been left over.

As far as I understand, the changes to the Building Energy Act 2023 apparently do not concern regulations for the building envelope, but the "primary energy demand." Does anyone know if these are "accounting tricks" or if the changes actually require the investments corresponding to the KfW55 house?
Are the expected energy savings really about 15% compared to KfW70/GEG2020 and thus definitely worth the additional costs, or is that wishful thinking?
We are a bit annoyed because the company did not inform us before signing about the expected changes and thus actually clear cost increases.

Thank you very much for your opinions!
Regards, Hansi

Your contractor surely has a specialist who must prepare the thermal insulation certificate for you, which you then have to submit to the building authority before construction begins. Why don’t you ask your contractor?

Of course we're asking, just wanted to know if anyone is familiar with it. The amendment will also affect everyone who is currently planning and building next year.

Of course we ask him, just wanted to know if someone knows about it. The amendment will also affect everyone who is planning now and building next year.

We have been building since October and I believe the amendment does not apply to us. Therefore, I can't say much about it. Presumably, you won't get very far with just a gas heating system. I found the following on the Building Energy Act website: "The Building Energy Act came into force on November 1, 2020. Another amendment will come into force on January 1, 2023 (reduction of the allowable annual primary energy demand in new buildings from previously 75 percent of the reference building to 55 percent)." That sounds to me like EH55 will become mandatory.

As far as I know, the new regulation corresponds to the EH55, affecting everyone who has their building permit from next year onwards. You will hardly avoid a certain surcharge. But I would be more worried about this:

Construction start is expected around 08/2023 due to ongoing development measures. We signed the turnkey construction contract in August

What does it say for you regarding a fixed price if there is a year between signing and the start of construction? How much leeway do you have if the development is delayed?

The offer is linked to the construction price index. For us, it was the most transparent solution. However, we have a withdrawal option from the contract if we pay for the input and factory planning.