Advantages of KFW 40 Plus in General

I think it's a very good solution! It's a pity that KFW was not interesting for us last year... you can then invest the 5000€ in a pool table or something else nice :P

I want to briefly inform you about the concept we will most likely implement: gas condensing boiler with solar thermal and controlled residential ventilation with heat recovery. In addition, an adjustment of the components so that we reach KFW 55 using the reference values.

Solid planning without major experiments.

We are building exactly like this.

We got KFW55 without problems.

I would like to briefly inform you about the concept we will most likely implement:

Gas condensing boiler with solar thermal energy and controlled residential ventilation with heat recovery. In addition, an adjustment of the components so that we reach KFW 55 using the reference values.

Exactly like us! After the thermal bridge calculation by the energy consultant, the insulation thickness could even be reduced. We now have 24 cm hollow bricks and 12 cm ETICS, so a normal 36 cm wall thickness with a heat transfer coefficient as low as an almost twice as thick monolithic wall...

Would you still say that a KFW 40 plus house based on these values is not economically viable?

Hello Robin, I really like your question because it finally puts money aside for a brief moment and allows us to look for other criteria. I assume that you want to live in your house. Therefore, set at least 4 criteria and weight them: 1. Residential health 2. Living comfort 3. Ecology 4. Economic efficiency What does the ideal energy supply with heat and electricity look like for you? We came to a solution outside the KFW standards, which is implemented in a modern way, CO2 neutral, and permanently inexpensive for us to operate (10 kWp photovoltaic system with solar tiles, 2 wood stoves, 1 masonry stove, a few infrared heating panels, more wood grows on the property than needed, 2 instantaneous water heaters and 1 hot water heat pump with storage). We did not calculate whether the construction costs pay off, because the solution also includes visual components, making comparison difficult. How much does a stove cost? You also do not calculate the economic efficiency of a piece of furniture or wall covering.

10kWp photovoltaic system with solar tiles

may I ask which solar tiles you are using?

I don't think I'm allowed to say, because I got a negative point for it in one of my first posts.