GAS / SOLAR or GAS / Ventilation + Heat Recovery

Hello, the construction company is obliged to build us a KfW-70 house (if we sign). Therefore, I currently assume that the option gas heating./ventilation with heat recovery naturally meets the required standards just as well as gas/solar. But we will follow up on that again.

There has not been any direct energy consultation on this yet. KfW70 package (proofs and consumption forecast cost us 600.-) according to the construction contract. Does anyone else have an idea what might - roughly estimated - be the better alternative?

Hey.... so, I’m currently having the problem that I can’t see any answers to your question... but I also know that I did reply to you once. I hope it’s just a temporary problem, but I also want to say something about the answer I can see, even just as a layperson: With our contractor, only gas + solar is not eligible for KfW funding, but only in combination with controlled residential ventilation + heat recovery + better thermal insulation. If that or something similar has already been said, sorry!

Hello,

... the construction company is obliged to build us a KfW-70 house (if we sign).

Since I also work as an expert/appraiser, here is a case example.
The builder was promised a KfW 40 according to the conditions valid at the time (2008). In subsequent operation, the builder noticed a significantly excessive consumption.
The expert reassessment showed that the building barely meets the conditions of the energy saving ordinance valid at that time. Currently, a lawsuit is pending.

...Therefore, I currently assume that the option gas heating/ventilation with heat recovery of course also meets the required standards like gas/solar. But we will follow up on this again.

Not only the KfW conditions have to be met, but also those of the EEWG.

... and consumption forecast...

I would like to see that.
The nicest calculation on paper is of little use if the execution of the system is not carried out in compliance. This is often where it fails.

best regards

....With our construction company, only gas + solar would not be eligible for KfW funding, but only in combination with controlled residential ventilation + heat recovery + better thermal insulation.

How does he come to that conclusion?

Best regards.

Hello,

it is certainly true that there are several requirements. We will add another 12cm of insulation to the massive exterior wall. The roof is insulated with 24cm and the triple-glazed windows have a u-value of 0.7. However, the discussion shows that we should follow up on this again.

Thank you!

With our builder, only gas + solar would not be eligible for KfW funding, but only in combination with controlled residential ventilation + heat recovery + better thermal insulation. If this or something similar has already been said, sorry!

Strange, it should actually be possible. We achieve KfW 70 with gas and controlled residential ventilation + heat recovery. We decided against solar, but the insulation had to be improved instead.

@Brian73
Regarding the ventilation. We were also offered the Lunos devices. They are certainly not bad, but you should consider whether to opt for a central controlled residential ventilation system. You should find plenty of discussions about the pros and cons...