Questions on Energy Demand Calculation KfW 70

Good day everyone,
I have been reading along here for some time and would like to ask my first question today:

We are building a two-story solid house without a basement with a developer, which is to meet the KfW 70 requirements (Energy Saving Ordinance 2009). For this purpose, I have received a fairly detailed energy demand calculation with individual evidence.

The energy demand calculation concludes that the requirements are met due to the specific transmission heat loss and the floor-area-related annual primary energy demand. --> Proof Kfw 70 fulfilled.....

But:
1) Component calculation ground slab: U >= 0.35 W/m²K
2) Component calculation upper floor ceiling with screed: U >= 0.2 W/m²K (+0.008)

Overall, I understand that the partly somewhat worse thermal insulation (Energy Saving Ordinance 2009) is compensated for by other measures such as solar energy or ventilation system.

Question:
Is this procedure formally acceptable if the individual proofs of the components do not meet the requirements of the Energy Saving Ordinance? This question is purely formal for me, regardless of other contractual contents.

Regards
der Käfer

Hello,

....to the conclusion that the requirements are met due to the specific transmission heat loss and the floor-area-related annual primary energy demand. --> Proof KfW 70 fulfilled.....

This means that the formality on paper has been accounted for.
Whether this is economically viable for the builder as a whole is a completely different matter!
[QUOTE="Käfer, post: 61644, member: 21415"]...Is the procedure purely formal acceptable if individual proofs of the components do not meet the requirements of the Energy Saving Ordinance?...[ /Quote] Why? The overall balance (comparison to the reference building) counts! Individual deficits can certainly be offset as long as the components each correspond at least to DIN 4108.
Example:
In proofs, the flat WB surcharge of 0.05 is often used! Completely legitimate and also permissible! However, it presupposes that all thermal bridges are executed according to DIN 4108 Part 2!
Who checks and supervises the execution in the interest of the builder? The site manager paid by the general contractor/prime contractor?

Best regards,

Tip: Compare the delivered exterior components regarding WLS or WLG with the proof (delivery notes)!

Thank you for the quick response.

I have also already considered the issue of monitoring, good point.

Again, from my layperson's perspective, a question on the topic "The overall balance counts, not the individual proof."
- Can I find a passage on this in the Energy Saving Ordinance? ((The Energy Saving Ordinance 2009 does prescribe <= 0.35 for the floor slab))

Next question:
Is it normal that in the energy demand calculation there is no reference to a range hood, e.g. with a wall box, or is this included and thus taken into account in other factors, etc.?

Regarding the U-value for the floor insulation, I hope you don't have underfloor heating?

I hope you don’t have underfloor heating with that U-value for the floor insulation?

The just over 0.35 W/m²*K is the U-value for the individual calculation of the floor slab. The insulation used has a thermal conductivity of 0.035 W/mK.
What U-value should a floor slab with underfloor heating have with reference to your general statement?

This formally meets the requirements on paper.
Whether this is economically viable for the builder is a completely different matter! (see post by €uro)

Maybe someone can explain to me again why the requirements of the Energy Saving Ordinance 2009 Annex 1 / Table 1 do not have to be met at least in a new build.
There the value for the floor slab is listed as <= 0.35 W/m²*K.

The just over 0.35 W/m²*K is the U-value for the individual calculation of the floor slab. The insulation used has a thermal conductivity of 0.035 W/mK.
What U-value should a floor slab with underfloor heating have with reference to your general statement?

Thus, the formal requirement on paper is met.
Whether this is economically viable for the builder as a whole is a completely different matter! (see post by €uro)

Maybe someone can explain to me again why the requirements of the Energy Saving Ordinance 2009 Annex 1 / Table 1 do not have to be met at least for a new building.
Because the value for the floor slab is listed there as <= 0.35 W/m²*K.

If the floor slab towards the underfloor heating has a thermal conductivity of 0.35 W/m²K, this is not really beneficial...
After all, the heating is located in the floor; if it is poorly insulated, the heat is conducted away through the floor slab.

Normally, one places a few centimeters of insulation under the underfloor heating and should thus get below 0.3 W/m²K, even if the floor slab itself is not insulated.