According to the energy certificate, do we not meet KfW 55?

Hello everyone,

I have been following the forum for some time for interesting posts about construction since we will be starting soon. Usually, I was able to find the answers from existing posts, but with this topic I am a bit puzzled and hope you can help me.

Today I received the building application from our general contractor (incl. structural stability certificate and energy saving ordinance), a single-family house according to KfW 55 is to be built. However, a look at the created energy performance certificate makes me doubt a bit, as it looks to me as if we will not meet the standard.

Information about the single-family house
- Aerated concrete (36.5 cm)
- Central ventilation system with heat recovery (min. 88%)
- District heating (primary energy factor 0.70 %)

According to the energy performance certificate
Primary energy demand (q_p)
Actual value 40.1 kWh/(m*a^2) --- requirement value 56.3 kWh/(m*a^2) --> undershooting by -28.7%

Building envelope (H_t)
Actual value 0.26 W/(m^2*K) --- requirement value 0.38 W/(m^2*K) --> undershooting by -30.9 %

As far as I understand, the building envelope (H_t) is okay, but not the primary energy demand (q_p), this would have to be at least -45% to fulfill KfW 55.
Is this correct so far?
If I am right and the primary energy demand does not meet KfW 55 requirements, then the following statement from kfw.de confuses me

"The requirements for a KfW Efficiency House 55 are met if [...]"

"For the system technology, one of the 6 following system concepts must be implemented."

"2.) District heating with certified primary energy factor fp ≤ 0.7, central ventilation system with heat recovery (heat supply rate > 80 %)"

How does this fit together, according to the above statement KfW 55 is achieved but not according to calculation?

I hope you can help me, as we wanted to submit the building application on Monday to have a closed shell before winter.

Thanks in advance!

Best regards
Robert

Wouldn't it be easier and safer to be patient over the weekend and call the engineering office that issued the ID on Monday? Karsten

Yes, I would definitely do that first thing on Monday. However, I wanted to hear another opinion on it, if someone is familiar with it or had a similar problem. By the way, which I forgot to mention, elsewhere the permissible maximum value (annual primary energy demand) is also given as 75.03 kWh/m^2. If I compare the calculated value with the maximum value (instead of the target value), then it also fits with KfW 55 ...

Just multiply your demand by the factor of district heating. Then it will match quite accurately.

What you are quoting from the KfW refers to KfW55 according to reference values.

For you, KfW55 was calculated and therefore the corresponding sentence has no meaning for you.

I assume that what you call requirement values are the reference values of the Energy Saving Ordinance calculation. I would agree with you: your primary energy demand is too high ... it may be max 0.55x56.3=30.9 ... you have barely passed the Energy Saving Ordinance.

Why this is so, your energy consultant can tell you.

But if you have a KfW loan, it gets exciting now ...

Calculate your demand multiplied by the district heating factor. Then it fits pretty accurately.

The primary energy demand already takes the factor into account.

But I find it strange that the primary energy demand is so high, when local heating with a factor of 0.7 is actually very good. In addition, there is the controlled residential ventilation with heat recovery, which significantly reduces the heating load (this could already be the error in the calculation) and thus reduces the energy demand for heating. The requirement value is, in my opinion, 64.35 kWh/(m²a) according to the Energy Saving Ordinance 2016, of which 55% = 35.3925.

H’T fits with 0.26, the target should be 0.28 for detached buildings.

Just ask. We are just laypeople here and all the rules for surcharges/deductions... well, at least I don't know them all.