ᐅ Determining from the energy performance certificate of a KfW 40 or KfW 55 house

Hello dear forum,

Is it possible to determine from an energy performance certificate whether a house meets the KFW-40 or KFW-55 standard?

From the line:

Primary energy demand
Actual value 23.5 kWh/(m² a) (7.3 kBtu/(ft² yr)) and requirement value 68.6 kWh/(m² a) (21.4 kBtu/(ft² yr))

I assumed that since 23.5/68.8 = 0.34, this would correspond to a KFW-40 house (actually even a KFW-34 house), or am I mistaken?

Energy performance certificate:

Best regards
leisinger

We have a KfW 70, but the energy demand is lower than that of a KfW 55.

Basically, you can assume this if

there is a ventilation system and a heat pump.

In addition, an energy consultant is required to provide proof regarding thermal bridges.

The blower door test must be below 1.

But why do you want to know the exact details? The values on the energy performance certificate are decisive for calculating the heating costs.

Thank you for your response. To better classify the building and for comparison purposes, it is important to know whether it is a KfW 40 house or not.

Best regards,
leisinger

In my opinion, for KFW-40 the transmission heat loss is too high at 62% (= 0.23 / 0.37), but it is sufficient for KFW-55.
(This information comes from the "Appendix to the KFW Energy Efficient Building Fact Sheet")

Best regards

Hello,

All clear, thanks. So you just need to divide the actual value by the required value – see the energy performance certificate – and then check in the "Appendix to the Energy Efficient Building Information Sheet" [B]We have now installed even better windows, so with H'T/H'T_Ref = 0.56 we basically have a KfW 40 house.

Here is the table:
KfW Efficiency House 40 Plus | 40 | 55 | 55 Reference Values
QP in % QP REF 40 | 40 | 55
H’T in % H’T REF 55 | 55 | 70