Hello everyone,
We are very close to submitting our building permit / planning permission application.
But now the problem.
We always wanted a gas heating system combined with something modern (e.g., gas with solar thermal or a fuel cell) and to meet the KfW-55 standard. The combination with something modern should qualify for KfW-55 (this has already been clarified with KfW advisors).
However, the construction company claims this is not possible and that an air-source heat pump must be used instead (I assume because this is simply their standard and itâs the quickest and easiest option for them).
After some back and forth, the architect responsible for the building permit proposed the following: She plans to include an air-source heat pump in the permit application (since it definitely meets the KfW-55 standards) and we would first obtain the permit to avoid construction delays (we already have a contractually fixed timeline).
In the meantime, the company will calculate the KfW-55 specifications for the gas options described above. The company claims this will take a long time and we would lose a lot of time if we wait for that.
She said that later, regarding the changed heating system, we would simply need to send a ânotificationâ to the building authority, and that would settle the matter.
1) Is this true? Are they really that indifferent to the heating system?
2) However, arenât there other problems, for example with the KfW-55 application, which would theoretically have been submitted but with a different heating system?
3) Regarding the fuel cell, we were told that the KfW 433 application must be submitted prior to the start of construction⊠but that does not mean âwith the building permit application,â right?
Thanks in advance!
Best regards
Kerstin
We are very close to submitting our building permit / planning permission application.
But now the problem.
We always wanted a gas heating system combined with something modern (e.g., gas with solar thermal or a fuel cell) and to meet the KfW-55 standard. The combination with something modern should qualify for KfW-55 (this has already been clarified with KfW advisors).
However, the construction company claims this is not possible and that an air-source heat pump must be used instead (I assume because this is simply their standard and itâs the quickest and easiest option for them).
After some back and forth, the architect responsible for the building permit proposed the following: She plans to include an air-source heat pump in the permit application (since it definitely meets the KfW-55 standards) and we would first obtain the permit to avoid construction delays (we already have a contractually fixed timeline).
In the meantime, the company will calculate the KfW-55 specifications for the gas options described above. The company claims this will take a long time and we would lose a lot of time if we wait for that.
She said that later, regarding the changed heating system, we would simply need to send a ânotificationâ to the building authority, and that would settle the matter.
1) Is this true? Are they really that indifferent to the heating system?
2) However, arenât there other problems, for example with the KfW-55 application, which would theoretically have been submitted but with a different heating system?
3) Regarding the fuel cell, we were told that the KfW 433 application must be submitted prior to the start of construction⊠but that does not mean âwith the building permit application,â right?
Thanks in advance!
Best regards
Kerstin
M
Mottenhausen25 Nov 2018 23:18Honestly, I expected it to be that simple.
Until the email from the energy consultant arrived: "completely insufficient."
Itâs not generally a difficult task, but compared to the design with an air-to-water heat pump heating system, unfortunately it is. Thatâs actually the unfair part. The house heated with an air-to-water heat pump is allowed to waste so much more heat than the one heated with gas, and itâs still classified as a KfW55 house... :-(
Until the email from the energy consultant arrived: "completely insufficient."
Itâs not generally a difficult task, but compared to the design with an air-to-water heat pump heating system, unfortunately it is. Thatâs actually the unfair part. The house heated with an air-to-water heat pump is allowed to waste so much more heat than the one heated with gas, and itâs still classified as a KfW55 house... :-(
Of course, thatâs possible. We also have gas, solar, and a central controlled residential ventilation system, and according to calculations, our house qualifies as a "KfW 60 house." So it doesnât quite reach KfW 55, but itâs closer to KfW 55 standards than to KfW 70.
If we were to add perimeter insulation below the basement slab, thicker insulation on the basement walls, and thicker exterior walls (we already have TV7 bricks), that should easily be enough.
However, whether this is financially worthwhile is something I would cautiously doubt.
If we were to add perimeter insulation below the basement slab, thicker insulation on the basement walls, and thicker exterior walls (we already have TV7 bricks), that should easily be enough.
However, whether this is financially worthwhile is something I would cautiously doubt.
How important is KfW 55 certification to you as builders? Is it just because everyone else is doing it? Or is it like having a leather-wrapped steering wheel in a Golf? Or is it about the subsidy and the loan? Or is it about genuine environmental concerns? If the latter, then aim straight for 40+.
Otherwise, what others have or what is common doesnât really matter. And the subsidy? The extra cost of an air-to-water heat pump compared to gas with solar basically cancels it out. And the loan? Itâs not especially favorable; you can get a bank loan with similar interest rates. In conclusion, drop KfW 55, gas and solar pose no problem at all. K.
Otherwise, what others have or what is common doesnât really matter. And the subsidy? The extra cost of an air-to-water heat pump compared to gas with solar basically cancels it out. And the loan? Itâs not especially favorable; you can get a bank loan with similar interest rates. In conclusion, drop KfW 55, gas and solar pose no problem at all. K.
Nordlys schrieb:
How important is KfW 55 certification to you as builders? Is it more about following the trend, like âeveryoneâs doing itâ? Or is it about having a feature similar to a leather steering wheel in a Golf? Or is it primarily about the subsidy and the loan? Or is it genuinely about environmental concerns? If the latter, then definitely 40+.Or does the development plan require KfW 55?
M
Mottenhausen27 Nov 2018 13:39Nordlys schrieb:
The extra cost of an air-to-water heat pump cancels out the savings from gas with solar.Do you even read? The homeowners specifically do not want an air-to-water heat pump.
The only additional cost for KfW55 standard is the controlled ventilation system, which basically pays for itself through the KfW55 subsidy (âŹ5000). So itâs practically free.
If you want to build a well-insulated house anyway, for whatever reasons: a higher personal comfort temperature well above 22°C (72°F); open spaces with air volume between floors; no vestibule in the hallway, and so on.
Why not take advantage of the KfW55 subsidy then?
Most likely, KfW55 today equals the next energy efficiency regulation of tomorrow. Building to this standard now canât be all wrong.
Of course, if you have to pay extra for wall construction, subfloor insulation, etc. just to meet KfW55, then itâs not worth it.
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