ᐅ GAS / SOLAR or GAS / Ventilation with Heat Recovery

Hello, the construction company is obligated to deliver a KfW-70 house (if we sign the contract). Therefore, I currently assume that the option of a gas heating system/ventilation with heat recovery naturally meets the required standards just as well as gas/solar. However, we will follow up on this.

There has not been a direct energy consultation on this yet. The KfW 70 package (certifications and consumption forecast cost us 600.-) according to the construction contract. Does anyone have an idea what might be the better alternative, roughly estimated?

Hello... I’m currently having the issue that I can’t see any answers to your question... but I also know that I did reply to you before.
I hope it’s just a temporary problem, but I would like to comment on the answer I can see, even if only as a layperson:
For our builder, a system with only gas plus solar would not qualify for KfW funding, but only in combination with controlled residential ventilation with heat recovery and improved thermal insulation. If this or something similar has already been mentioned, sorry!

Hello,

brian73 schrieb:
... the construction company is obligated to deliver a KfW-70 house (if we sign).

Since I also work as an expert/appraiser, here is a case example.
The client was promised a KfW-40 house, according to the standards valid at that time (2008). After moving in, the client noticed significantly higher energy consumption.
The expert review revealed that the building barely meets the requirements of the energy-saving regulation valid then. Currently, there is a lawsuit pending.

brian73 schrieb:
... Therefore, I currently assume that the option of gas heating/ventilation with heat recovery naturally meets the required standards just as well as gas/solar. But we will follow up on that.

It is not only the KfW requirements that need to be met, but also those of the Renewable Energy Directive (EEWG).

brian73 schrieb:
... and consumption forecast...

I would like to see that.
The most thorough calculation on paper is of little use if the system is not installed according to the specifications. This is often where problems arise.

Best regards.

ypg schrieb:
....With our builder, only gas + solar is not eligible for KfW funding; it must be combined with controlled mechanical ventilation with heat recovery and improved thermal insulation.

How does he come to that conclusion?

Regards

Hello,

It is certainly true that there are several requirements. We will add an additional 12cm (5 inches) of insulation to the solid exterior wall. The roof is insulated with 24cm (9.5 inches), 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!

ypg schrieb:
With our builder, gas plus solar alone does not qualify for KfW funding; it only works in combination with controlled residential ventilation with heat recovery and improved thermal insulation. Sorry if this or something similar has already been mentioned!

That’s strange, it should actually be possible. We achieve KfW 70 standard with gas and controlled residential ventilation with heat recovery. We decided against solar, but had to improve the insulation instead.

@Brian73
Regarding ventilation: We were also offered the Lunos units. They are certainly not bad, but you should consider opting for a central controlled residential ventilation system. You can find plenty of discussions on the pros and cons...