KfW-70 standard not reached (bungalow)

If we had the money "left over," we would probably install one as well. But unfortunately, we don’t, and we have to calculate strictly and tightly. All your arguments are understandable to me.

We are now used to ventilating a lot in our new apartment. My partner works shifts, so the house only has to be "unventilated" for 6.5 hours during the early shift week.

What role does a planned wood-burning stove with separate fresh air supply actually play in the decision regarding a ventilation system?

Did you submit the building application in 2015? A central ventilation system costs around €7000-9000 in the area depending on the manufacturer and house size. May I ask where you are building in Nordhorn, feel free to send a PM.

Building application was submitted to the building authority before Christmas.
Our contractor also told us about €7000 - €8000.
I'll send you a PM right away.

Wood stove with chimney costs the same, if not more, and is "just" a cozy nice-to-have...

Hello f-pNo,

Well - the building layman rather speaks of the KfW70 standard and means the KfW70 efficiency house.

I am aware of that; nevertheless, "opinion" and "certain knowledge" are two different things. But it is a very good example of why I repeatedly advise checking BB and contracts carefully.

Hello again

KfW-70 standard for me is a KfW-70 efficiency house. I work in real estate and deal with energy certificates daily.

In leasing?

Of course, we have a written offer and that is also the basis for everything. We will only sign the construction contract this week.

So no online form has been filled out yet; who calculated what and why at this point in time? The form would have been the first thing that would be due in my opinion; the structural engineer usually only calculates after the submission of the unconditional building permit.

We have a lot of problems with moisture. According to our landlord, that is due to the fast construction.

That is mainly caused by a missing ventilation system; if given the choice again, your landlord would surely decide differently.

I called the builder again and also expressed my dissatisfaction. He explained that you can never say 100% in advance whether the building project will meet the standard. The requirements and the calculation of the values have changed so much. We just have to accept that now.

Honestly, I find this statement borderline. It would have been part of his duties - KfW 70 has been around for quite a while - to inform you about the steps needed to actually get certified as a KfW 70 efficiency house. The building envelope is only one component.

1. Improvement of insulation technology: e.g., insulation under the concrete slab, better cavity insulation. The work itself would not cause that many additional costs, but rather the necessary documentation by the engineer for the KfW bank.

Probably according to the 15% rule. What kind of heating technology is to be installed?

2. Ventilation system

I would always recommend that; f-pNo, as well as Musketier, have understandably explained the advantages of such a system. Depending on the house size and system, costs are around €6,000 for a decentralized system and €14,000 for a central controlled residential ventilation system with heat recovery.

Rhenish greetings

Moin Moin

You now live in a newly built house and have problems with moisture.
You come from the real estate sector and deal with energy performance certificates.
Do you just file them away?

The contractor’s approach is, in my opinion, great:
They design the house for you in the desired standard and present the offer and contract accordingly.

Olli