ᐅ Upgrade from KfW 55 to KfW 40+

Roppo schrieb:
@FHW6Neu
What exactly is your post meant to demonstrate in this context?
I mean, the subsidies are well known, and it wasn’t about how to achieve 40+.
So please help me understand what you are trying to express here.

The point is not wrong, since your initial post only mentioned the extra cost for KfW 40 (i.e., more insulation), the photovoltaic system, and the battery storage to reach KfW 40+. But that's not enough. You also need controlled residential ventilation with heat recovery, as well as visualization of electricity consumption. Both are definitely not free of charge.
I’m not a fan of battery storage; on the contrary, I think manufacturers consistently mislead consumers with extremely shortened payback calculations. Still, if you want a battery, purchasing it at the same time as the photovoltaic system has a significant advantage: you can claim VAT on the battery as well. This is no longer possible afterward, because the tax authority assumes the battery is purely for private use and not related to business.
If you keep this in mind and choose a small battery (i.e., a lower investment), then achieving KfW 40+ can work out, assuming the rest of the technology is desired anyway. The real cost jump is from 55 to 40, because that requires more insulation.
It gets really good if you can allocate one battery for two residential units … then you receive a double repayment grant.
By the way, I don’t think a battery adds value to your house. Unless you plan to live there for only five years before selling it, the battery won’t even be there when you sell the house. So forget that sentimental argument. Either the battery pays off over its lifetime (a very tricky prediction), or it doesn’t. Beyond that, there’s no benefit to expect.

Photovoltaics – are you building with a heat pump, key word self-consumption? In that case, a battery won’t significantly increase self-consumption if the heat pump is well synchronized with the photovoltaic system. Moreover, you can also consider the heat pump as storage, since it converts electricity into heat, which will remain stored in your KfW 40 house for a long time.

Hello Alex85,
thank you for your reply. I just wanted to clarify the KfW 40 Plus requirements a bit more....
I myself am building a house with two residential units in autumn 17, meeting the KfW 40 Plus standard, which allows me to receive a repayment subsidy of €30,000. Photovoltaic panels and controlled mechanical ventilation are already included in the house price, so I can easily use the additional funding from KfW 40 to 40 Plus for the battery storage...

Now I understand the comment as well – I probably wasn’t clear enough before.
For my KfW 55 house, €11,000 (about $12,000) is enough to upgrade the standard to KfW 40, including everything necessary. That’s how I arrived at my calculation; if there were additional costs beyond that, the whole consideration would not make sense.

So again, after deducting all costs and subsidies, the surcharge from KfW 55 to 40+ is only €5,800 (about $6,300)!
Unless I have overlooked something important (and by that, I don’t mean whether everything required for KfW 40+ has been included, because that point is clear).

The question is whether the initial calculation with the subsidies can be done that way and whether, in your opinion, it makes sense to pay the €5,800 (about $6,300) surcharge to reach KfW 40+.

Edit: Of course, if I choose a small storage unit, the final surcharge would be even lower...

It is often said that whoever is given a responsibility by God is also given the wisdom to handle it. An old saying among civil servants. So, don’t disable it. Everything you install can also fail. What isn’t installed cannot break. I’m telling you this as the owner of one of those blue motion cars, while my wife’s Twingo runs very, very smoothly without all the electronics and assistance systems.

You can do the calculation that way. However, it is probably not very practical.

I’ll link to my own post here.

https://www.hausbau-forum.de/threads/hat-sich-schon-jemand-mit-dem-sog-Store-Paket-der-fa-Solarwatt-befasst.16947/page-2

You’re certainly right, Nordlys, that one should always have the courage to use their own judgment. Ultimately, that is what it comes down to. However, for me, there is also a longer process of forming an opinion that I am currently going through. I don’t think it’s as simple as just saying “this is all nonsense and never worth it.” Otherwise, there would be broad agreement on the matter, which is not the case. Some even go beyond that when building Passive Houses or similar standards.

For me, the crucial question is: at what point does it make sense?

There are certainly different opinions on this, and I believe the truth lies somewhere in between. That’s why I want to hear arguments that I can evaluate for plausibility.

Regarding all the technology involved, which is probably the most likely to fail early on, it is already fully installed in my KfW 55 house.
So here we are only talking about additional insulation in walls, ground loops, roof, and windows, as well as the storage unit as the only technical component for a 40+ standard.
These roughly make up the costs.