Good evening,
He, 26, monthly.
She, 24, monthly.
What we have chosen now would cost €30,000 including connection. We have looked at several shell houses and have already obtained several offers. We would be around €100,000-120,000. But then turnkey; as a shell house we would be at around €90,000.
We would like to pay no more than €800-900 monthly because we are building a passive house; the additional costs are limited, but we would like to save something aside for possible special payments.
How do you estimate that?
You are still very young; in my opinion far too young to read or to understand the many pitfalls of a construction specification (BB) or a contract for work. That only comes with increasing age and corresponding accumulation of negative experiences in all areas of life; we older ones have all been through that.
If it were possible to build a complete passive house (PH) for €120,000, the order books of the provider you favor would be filled for decades. I want to go one step further - there would be "only" this provider.
But since we do not live in a "wish for something" world, but in reality, get professional help and have the BB and contract checked with its help; I suspect you would not believe the users here anyway. Your focus is too much on the desired house and the tempting number at the bottom right. Unfortunately, you already fail to realize that as a tenant, you are not the fool here.
I further suspect - you have not yet provided information that a 130 sqm house is intended. Realistically, costs for the turnkey and solid variant are around €188,500 for a KfW 70 efficiency house. Since you are interested in a prefab house, the costs will be roughly comparable, probably higher (due to production); if and insofar as your focus is on quality. In this respect - even Scanhaus Marlow Marlow® has nothing to give away - there has to be a catch. This catch is probably in the terminology, like the depths of the BB; therefore, the €120,000 probably refers to a shell house: closed shell and sanitary as well as electrical rough installation including screed. The rest (not really little) then lies in your hands. For €120,000 I would guess a closed shell; that still roughly fits the figure mentioned.
The step to a real passive house (PH) will probably incur costs of about €45,000-65,000 - whether solid or prefab; for ventilation, additional insulation and photovoltaics including storage.
I am rather appalled that the banks you approached have not advised you against the project; have not shared any experience with the desired provider. The "language" of the competition no longer surprises me, however.
Before you even think about signing a piece of paper: get professional help (expert, VpB, BHSB, lawyer, etc.). And internalize this: very cheap always means very expensive in the end.
Rhenish regards