How to achieve KfW40? Energy technology / Economic efficiency

  • Erstellt am 2020-12-29 22:25:19

user386dx

2021-01-02 12:30:50
  • #1


Hello, if you have the storage and the photovoltaic system subsidized, you are not allowed to feed energy into the grid. Furthermore, the feed-in period of a photovoltaic system without subsidy is only 20 years, therefore it is sufficient if the modules have only a 20-year warranty, because then you replace the system. At least that was the case under KFW 153, how it is handled with the BEG is still pending; we are still waiting, also with the construction. Happy New Year.


    [*]We would like to achieve KfW40 standard. What measures do you suggest/are mandatory?

- thermal envelope with at least 42.5 bricks (preferably brick instead of aerated concrete etc.)

    [*]We have read very positive texts about the economic efficiency of photovoltaic systems with east-west orientation on flat roofs. How do you assess this for our max 30-degree pitched roof? And better 25 or 30 degrees?

- ask here in the forum, possibly solar cadastre, shading, orientation and system calculation with PVSOL. No satellite dish on the roof and no windows either but fully the roof ;)

    [*]Does a storage system make sense?

- opinions differ on whether a storage system makes sense and the facts are clear, no, it does not, but it is an expensive toy & for KFW40+ under the BEG it is no longer clearly prescribed, as the WG (residential construction) more focuses on achieving certain energy values instead of "technical systems."

    [*]Are there module manufacturers you would particularly recommend?

- Heckert, Q-Cells, LG, and many more.

    [*]Can you recommend an energy consultant and/or an expert for the installation of photovoltaic systems in the Ruhr area/Sauerland?

- no, sorry, I don't know anyone there, we come from Saxony.
 

RotorMotor

2021-01-02 12:44:23
  • #2


For which subsidy is that supposed to be the case? With KFW153 this statement is wrong -> 60%+ soft
 

user386dx

2021-01-02 12:59:14
  • #3
Hello, sorry, I meant sealing for example at 273 at 50% and at 153 at 60%. Although ew is changing now. Regards
 

pagoni2020

2021-01-02 13:10:19
  • #4

Thanks for the info!
If I achieve Kfw40Plus through structural measures, then the construction is subsidized and not directly the purchase of the photovoltaic system or the storage. According to my previous understanding, I was "forced" to include a storage with Kfw40Plus. So why should feeding in be forbidden? We are in Saxony, and there is no very high subsidy for the battery.
Am I mistaken? Where does it say that you are not allowed to feed in then?

In 20 years I will be over 80... so this question is less relevant for me. Besides, I don’t have to replace something just because the warranty has expired. Mathematically, many technical systems are probably outdated and technically obsolete after fewer years. The 30-year warranty is not a decisive feature for me, although it rather speaks FOR a decent quality of the product; I will probably decide in favor of the electrician who distributes this product. So I would also accept it if it were only 20 years or 15.
Could you give me concrete sources for your statements before I search myself endlessly? That would be really nice.

It also works with 36.5 here with us and yes, aerated concrete is rather more difficult/hardly possible. Whether you then take a filled 36 cm brick, 42 cm, or external insulation... all of that is ultimately just calculations by the energy consultant. For us it will be 36.5 brick plus various insulation measures.

Sorry, I can’t find this anywhere, maybe you can help with sources.
 

pagoni2020

2021-01-02 13:38:03
  • #5

So am I correct in assuming that if I build according to Kfw153 into Kfw40Plus, among other things I need a storage system, but I am still allowed to feed in. Provided I received a subsidy from the federal state for the storage system, this would also NOT be an obstacle, neither for feeding in nor generally for the subsidy. Right?
 

pagoni2020

2021-01-02 14:47:32
  • #6

For blondes in simple words, what does "curtailment" mean? Or what are the consequences?
Our system will probably have at least 9.8kWp, possibly a bit more. However, not 20 or 25.
 

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