ᐅ Building Energy Act vs. KfW55 vs. EH55: Simple Explanation of the Differences in New Construction (As of 2025)

Hello everyone,

I have been reading this forum for a while, and now we might start building. We have already had some discussions with a few mostly regional general contractors in Middle Franconia / Bavaria.
Some of them asked whether we want an EH55 or KfW55 house, or just to comply with the building energy regulation. I am confused about this. Until now, I thought that every new build must comply with the building energy regulation, which currently states that a single-family house may only have a primary energy consumption of 55% compared to a reference building. I assumed that this corresponds exactly to EH55 or KfW55.

There are many websites about the building energy regulation / KfW55 / EH55, but many refer to outdated information or do not explain the differences, if there are any.

Could you please clarify for me what the difference is as of December 2025 between these three types: minimum standard house according to the building energy regulation versus efficiency house 55 according to KfW55?

Thank you.
VielleichtBau

I’m not an energy consultant, but as I understand it, the requirement for overall energy consumption remains the same. However, the requirement for transmission heat loss is more lenient according to the building energy law.

In practice, this means the overall energy consumption can also be met through modern heating and energy generation systems (such as oil heating, heat pumps), whereas with EH 55 the building’s insulation needs to be better.

I built according to GEG2020 standards, and the house achieves a primary energy demand of 47 kWh/m²/year, which was roughly the maximum allowed.

So, it probably doesn't matter much what you end up building. It depends on the budget.

For the actual gas consumption of 10,000 kWh, I pay 1,200 EUR/year. You have to consider whether it’s worth spending 50,000 EUR to halve that.

VielleichtBau schrieb:

Can you clarify for me what the difference is as of December 2025 between these three types: minimum standard house according to the Building Energy Act versus Efficiency House 55 versus KfW 55?

The prices are roughly the same. Energy consumption is practically the same as well (because all require the same energy use). The only difference is in insulation: the Building Energy Act is less strict than the KfW Efficiency House standard (so better technology can compensate for the lower insulation requirements).

A Building Energy Act house is also an Efficiency House 55 because it demands the same energy consumption. The KfW 55 house (but forget about the subsidy, you won’t get it anymore) is also an Efficiency House 55 with the additional requirement of better insulation than the Building Energy Act/EH55 standard.

MachsSelbst schrieb:

I built according to GEG2020 and the house achieves a primary energy demand of 47 kWh/m²/a, which was basically the maximum allowed.

So, it probably doesn’t matter much in the end what you build. It depends on your budget.

For the 10,000 kWh of actual gas consumption, I pay 1,200 EUR/year. You have to consider whether it’s worth spending 50,000 EUR to cut that in half.

Anyone building new today will build according to the Building Energy Act anyway. The difference to a subsidized KfW 55 house is hardly noticeable in price (at least as far as pure construction costs go). For 50,000 EUR more, you get a subsidized KfW 40 house.

And whoever has 1,200 EUR heating costs for a new build today is either doing something wrong or building a 300 m² (3,229 sq ft) house.

The OP’s question is aimed at something else. When requesting quotes, he receives the follow-up question whether he wants to build according to the Building Energy Act or if he needs to meet a funding standard.
The OP believed that according to the Building Energy Act, the funding standard KfW (=EH) 55 must be met.
The answer is, as mentioned, that he needs to meet the primary energy demand. The building envelope, however, could be according to the reference building.

I think the new funding pool will be empty after just a few days, so it doesn’t really make sense to plan with KfW55 funding.

Build it as cost-effectively as possible; the energy standard according to the Building Energy Act is already great.
And a central ventilation system isn’t free either... it consumes electricity...