which energy standard is being built

@all

I finally received a 'written' response from KFW Bankengruppe today and do not want to withhold it from you.

thank you for your inquiry.

We are pleased to inform you about our product conditions regarding independent experts in the product "Energy-efficient Construction." These apply to all KfW efficiency house standards.

The expert must be commissioned for the construction project in an economically independent manner. In addition to consulting, planning, and construction supervision for the project, the expert must neither be in an ownership, partnership, or employment relationship with the construction companies or suppliers involved nor mediate deliveries or services.

The following are not subject to this regulation:

- experts employed by the applicant or seller (e.g., property developers) of new residential units
- experts employed by construction or craft companies (e.g., prefabricated house builders), whose products and services are defined and monitored according to quality assurance.

Kind regards,
KfW

So, nothing really new. Another response is still pending; I am waiting for news from our expert in energy efficiency.

Rheinische Grüße

As far as the facts are concerned, nothing new. Why should anything have changed there?

I am commenting on the question posed at the beginning of the thread:

We built extensively in 2014 and chose the KfW70 standard. The effort for this was relatively low; further measures would never have been cost-effective for us in relation to the savings (energy/interest rates). So now we have a well-insulated house at a reasonable price.
As a heating system, we decided against the widely hyped air-water heat pump* and installed a conventional gas heating system. In addition, we have vacuum tube collectors on the roof as the primary energy source for heating and hot water; they are so effective that even in winter under overcast skies they almost heat the water by themselves.
All in all, we chose what I consider the best price-performance ratio. Let’s see what costs we will have after the first full year.

________________
*The many reasons against it would go beyond the scope here and it’s not the topic.

Yes, yes, the lovely theory
The problem with your way of thinking is as follows:
You built House A and thought about House B (worse) and House C (better). I assume House A causes costs of 1000EUR per year. How do you know what costs House B and House C will cause? ...800? 1200? And as has already been mentioned, the jump from 100% to 80% is cheaper than from 70% to 60%. So where is the golden limit for the builder with x residents in town y with budget z and their habits?
Besides, you probably have not made the effort to have House B calculated just as thoroughly as House A ultimately was (and you won’t do it anymore... the price is already outdated). And who is interested in proving to themselves that they made a thinking or calculation error? What does your energy certificate say and what will reality be?

For me, this is not really comprehensible and there are surely some calculation errors in the math. Oh yes, what is often forgotten are the follow-up costs and interest that arise (e.g. in controlled residential ventilation easily recognizable).

I find it important to think about the possibilities and be careful when calculating, because everyone calculates differently!!! The energy consultant calculates with different numbers than the banker or the seller for the air heat pump, controlled residential ventilation, or whatever. Who calculates correctly? My guess... no one! Because the basis of the calculation are numbers lying in the future and who can predict that? Once the decision is made, it’s water under the bridge anyway.

So now to my decision and reasoning

[*]Energy Saving Ordinance 2014 is mandatory, so that is initially the reference

[*]We are not building according to the KfW standard because I don’t know how I will refinance in 10 years and I am told that I have to meet the standard (whatever that means). I don’t want to be forced into this straitjacket. I don’t care if I reach 71% or 69%. We finance fully, clear costs, low risk. Yes, it is more expensive, but we can and want to afford it.

[*]Air heat pump with water storage, because I want to make myself independent from fossil fuels and keep the flexibility to decide whether my electricity comes from my own photovoltaics, nuclear, coal or whichever power plant. So I can choose my "electricity provider" myself. I suspect storage solutions for electricity will soon become cheaper.

[*]T9 36.5cm without additional insulation. I easily meet Energy Saving Ordinance 2014 requirements. Since I don’t have time to calculate all options and our supplier offers this stone as "standard." Standard for me means high demand -> lower price ... so I could very well be wrong! Tough luck

[*]Probably without floor insulation (3000EUR savings), we haven’t decided on this yet.

[*]Roof insulation definitely, as the cost/benefit ratio should be very good. Own labor possible!

[*]Windows, triple glazed with very good Uw and Ug values that are not significantly more expensive

[*]Without controlled residential ventilation, as the (follow-up) costs bear no relation to the investment. The actual benefit of a controlled residential ventilation is not "valuable enough" for me.

To what extent all this "pays off," I don’t know. No one will recalculate that for me. That’s why I try to use the standard offered on the market. "Older" material probably won’t be significantly cheaper! So this is rather a gut feeling to decide this way.

So the question "what energy standard to build?" can only be answered individually because one knows one’s own financial situation, wishes, and future circumstances best. So educate yourself as much as possible and build your own crystal ball. The more you calculate, the more secure you will probably feel that the decision was the right one ... rest assured, there is no wrong one.