ᐅ KfW 40 (plus) standard for a multi-family house cannot be achieved

KfW40, meaning among other things the following requirements necessary for loan approval, must be submitted:

• A power-generating system based on renewable energy
• A suitable, stationary battery storage system/electricity storage
• Reduction of feed-in capacity to a maximum of 60%

In other words, you must consume at least 40% of the solar energy production yourself(!), that is, within the building. Otherwise, there will be no loan, or if this is discovered afterward, you could be accused of fraud in the worst case. If you cannot meet this, there will initially be no funding, or the money will have to be repaid!

Do you live in the apartment building yourself? No? Then the residents must consume it. You must therefore bind them to an electricity contract and become the electricity provider yourself.

Have you considered the entire chain of consequences this entails? From an energy law perspective, the photovoltaic system operator becomes a utility company (electricity supplier) under the Energy Industry Act (EnWG) and must collect and pay the Renewable Energy Sources Act surcharge on every kilowatt-hour sold, as well as pay grid fees to the grid operators or the concession fee to the municipality, charge value-added tax, etc.

Legally, the electricity supply contract can be terminated. If it goes badly, tenants might take the lease together with the electricity contract because they fear they won’t get a rental contract otherwise, and then cancel the power supply contract after moving in. Then you’re in serious trouble! What do you want to do with all that electricity? Heat the garden pond to 40°C (104°F), or how will you meet your 40% quota? The financing and operating costs for the equipment still continue.

Good point—now calculate the cost of all the equipment and add your hourly rate for the administrative effort plus accounting fees as ongoing expenses. Still convinced?

This applies only to KfW40 PLUS!
And regarding electricity sales to tenants: it is all regulated under the keyword tenant electricity. The renewable energy surcharge does not apply here, but it is still complicated and time-consuming.

dertill schrieb:

Which U-value applies to each building component? Does each component meet the KfW40 requirements according to the individual component method? If so, great! You can skip the Q and Ht' calculations and use the alternative method. I already provided the source for information, which you can also share with your energy consultant for your next house.

Yes, each component meets the KfW40 requirements, but using the simplified KfW method with a thermal bridge factor of 0.03, the required values are not quite reached.
With my own calculation using the same program as a demo version, I experimented a lot to achieve the values; it is close up to the second decimal place... If I change one component, for example, the window from 0.87 to 0.88, the value exceeds the limit.
However, if the thermal bridge factor were calculated in detail and thus reduced, it would be possible to adjust values again.

Installing it in a demo version is not the solution! You have now been presented with several options.

So, what will you do now?

Zaba12 schrieb:

Installing it in a demo version is not the solution! You have now been given several options.

So, what will you do now?

I will meet with the energy consultant again to share what I have learned.