Advantages of KFW 40 Plus in General

Purely out of interest How was the degree of self-sufficiency over the whole year? How high is the savings compared to without photovoltaics with storage? Can you say how it would look if you had no storage but only photovoltaics

So for me it has paid off, or am I overlooking something?

Whether it has paid off you can only assess if you compare the consumption for the kfw55 house without the €15,000 surcharge and then extrapolate the savings over 20 years. Unless you received the €15,000 from the KFW without any additional costs or credit losses – then it certainly paid off.

Hello Lumpi,

yes, the 15k came from the KFW, so...

- we moved in August, but the photovoltaic yield/autarky has only been logged since the last week of October, so the total autarky is only at 20%,
extrapolated over the year - partly because I will probably consume quite a bit myself through cooling in the summer - I estimate 40-50%.

- we moved in August, but the photovoltaic yield/autarky has only been logged since the last week of October, total autarky is therefore only at 20%, extrapolated over the year - among other things because I will probably consume quite a lot myself through cooling in the summer - I estimate 40-50%.

Thanks, I'm curious. Keep us posted. We also want to install a system in a few years. With storage, if they become cheaper. Our mayor is currently testing one at his house.

I wouldn't wait any longer, the feed-in tariff is decreasing and who knows how much longer it will even exist... You can still retrofit a battery - but I suspect they will become more expensive rather than cheaper, because the demand for electric cars will increase drastically in the coming years.

Thank you very much for the lively assessments.

I would like 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 achieve KFW 55 through the reference values.

Advantages of the concept (in my opinion):
- Low heating costs due to gas condensing boiler and good insulation
- Possibility to replace the heating system with a fuel cell heating system in later years (depending on developments)
- Comfort and mold protection through controlled residential ventilation (all the more important with stronger insulation)
- €5,000 subsidy through debt relief and access to low-interest loans (0.9% with 10 years fixed interest rate)