Operate heat pump autonomously with photovoltaic system.

W How you nicely calculate your KfW40+ house would still interest me.

Without wanting to get personal, may I ask what happened to you? It seems it was a personal experience for you after all, right? Did you build with solid construction or why your disinterest in KfW 40 Plus? If you have understood the concept, there should actually be nothing against it.

It's a pity that the thread missed its goal.

No, the thread did not.

We can keep it very brief like this and leave it at that.

Thorsten

Without wanting to get personal, may I ask what happened to you? It seems to have been a personal experience for you, right? Did you build Massiv or why your disinterest in KfW 40 Plus? If you understand the concept, there should actually be nothing against it.

From my point of view, there are many arguments in favor of energy efficiency, sparing use of resources, and I think it's great when someone builds to KfW55/40/40+.

I also don’t know how you come to the conclusion that I’m not interested in KfW40+. Is that written anywhere?

On the other hand,

For me, profitability is the top priority.

Feel free to convince me otherwise! I would be thrilled if I am wrong.

I am building a timber frame construction, KfW55, ground source heat pump and controlled residential ventilation with heat recovery, and so on and so forth. I like the concept, but from today’s perspective it is economically nonsense. The construction costs are high compared to the energy saving ordinance house; the savings on heating costs with today’s electricity/gas prices are ridiculously small.

I don't understand how anyone can insist on the opinion that a house is not economical.

I never claimed that (any) house is uneconomical, but rather a typical single-family house that is inhabited by an average family alone.

In my opinion, it is simply not economical to live in over 100 sqm. It is a waste of space and resources.

It may be profitable if you sell it for more than you buy it. It is practical for family life and hopefully fulfilling for the individual persons and certainly many other things.

But it is not economical.

For me, it does not have to be, but for you, economy is apparently the top priority...

Hello. A second-hand photovoltaic system with a nominal power of 500KW is the solution! And... just for fun... the [Waermepyramide] from [graviflight] could also be good if it is really big...

Hello everyone,

I would like to revisit the topic of KFW 40 + here, deviating from the actual headline. I am currently also planning a new build; the current offer describes a KFW55 house (140sqm + 40sqm granny flat in the basement + 20sqm living basement = ~200sqm living space, air-water heat pump). Since the house is offered as KFW55, I would currently receive a €12,000 grant from the L-Bank. For a KFW40, it would be another €10,000 more; according to my provider, this should cover the additional insulation. For KFW 40 +, there would be another €10,000 grant; with this money, I could at least finance the photovoltaic system (~5-6KW) and possibly already part of the battery.

However, since 01.03.2016 there are new guidelines for the KFW program 275; unfortunately, I have not found many discussions about this yet, so the following questions arise:
- Is the combination of KFW 153 + 275 possible?
- Is a maximum grid feed-in of 50% realistically achievable? What happens, for example, in summer when the grid feed-in is higher?
- Are the common inverters and batteries already designed for the new requirements?
- Is the 10-year value retention guarantee already taken into account by the manufacturers?