KfW430: Efficiency House 115 without condensing boiler and basement insulation?

Hello everyone,

I recently met with a KfW energy consultant to discuss my project. Unfortunately, he seems to either only be familiar with the common KfW 151/152 topics and/or he leaves the details to his employee. He was hardly able to contribute any detailed knowledge during the conversation. Unfortunately, I have neglected the topic of energy consultants for too long. I would now rather not have to obtain several new conversations and offers. I hope to get an initial assessment of my project here in the forum, whether I am on the wrong track or not.

My project is to comprehensively renovate a semi-detached house from the 60s. Roof, facade insulation, windows, doors, heating system. The question is, can I achieve the efficiency standard 115 with these measures, but:
- without new condensing technology. I am converting the existing boiler (10 years old) from oil to gas.
- without basement ceiling insulation
- without regenerative energy components

Actually, I do not care which standard I achieve, but it must be at least 115. Do you think that would generally be possible? Can you even say without calculation? I mean, the 115 is worse than the Energy Saving Ordinance, and I have to comply with that anyway.

Thank you very much and best regards Tassimat

I have made some progress with my research. But feel free to correct me if I am wrong anywhere.

For an Effizienzhaus (115), the type of heating is completely irrelevant. The definition only considers the energy demand.

Since I do not want to install either condensing technology or solar thermal, no costs will be credited or subsidized for the heating system itself. But that doesn't matter: With the measures for roof, facade, and windows, I come close to the maximum eligible costs of €100,000.

To what extent I can reduce the energy demand of the house to the threshold for the 115 subsidy unfortunately has to be calculated. In the worst case, solar thermal must then be installed on the roof or insulation added to the basement ceiling. In return, there is €10,000 more subsidy.

On Monday I will meet a new KfW energy consultant directly at the house. This one seems much more committed than the previous one.

I had a similar problem. The first energy consultant had completely different ideas than I did and ignored and dismissed my suggestions. I then looked for another one who wants to implement my ideas or at least considers them feasible. As you have already recognized, a calculation for efficiency is needed. Mistakes can also creep in there or incorrect values and flat rates can be applied, so it's better to take an extra look.

I have since met the consultant and we have come to the conclusion that the effort for an energy-efficient house is unfortunately too high. An example: The entrance of the house is located on a landing in a kind of stairwell, so additional doors for thermal separation would be necessary, insulation of interior walls and the basement ceiling. Missing solar thermal and condensing boiler would not be exclusion criteria but negatively affect the calculation. The balcony is too unfavorable. Overall, the measures would exceed the funding by several thousand.