KFW 50EE or 40EE - Is the upgrade worthwhile?

we had a conversation yesterday with a construction company for the solid construction of a single-family house... The construction company decisively advised against KFW40 as additional costs of €18,000 are to be expected and definitely no central ventilation with heat recovery and enthalpy heat exchanger.... They install a decentralized ventilation without heat recovery and that is "super"...

How many conversations have you had so far and how many offers do you have?

Basically, I would accept the proposal favored by the general contractor under the motto "what he proposes, he can do well" or look for another general contractor, which in this case would be my personal choice.

Fundamentally, I would accept the proposal favored by the general contractor following the motto "if he suggests it, he must be good at it," or look for another general contractor, which in this case would be my personal choice.

Basically, my Steinemantra naturally applies in a similar sense to heating and air conditioning technology and so on. However, I would always prefer the builder with the best feeling and the second-best technology in the combination "test winner technology, but mediocre builder." With an architect and tendering, you can create a position in which some questions no longer arise or are already answered. The professional knows his people.

What I forgot - with 40 EE there would also be 7500 more funding... in total then 10500€ additional costs.

How many conversations have you had so far

That was our first - we have another one on Friday and then we want to see. How many should one roughly have?

What I forgot - with 40 EE there would also be 7500 more funding... in total then 10500€ additional costs.



Was our first one - we have another one on Friday and then we want to see. How many should one roughly talk to?

Depends on how much experience you can draw on from family & acquaintances.

For me (in the semi-rural area) there are three construction companies within a 3-kilometer radius. All three have an excellent reputation. In my case, I would talk to these three and leave it at that. With prefabricated houses, of course, it looks a little different.

But still: never exclude those directly on site (as long as the reputation fits)

Talking now with the two most well-known in the room. Possibly also with a third with whom the colleague is currently building - however, I am not okay with the ventilation manufacturer being changed during the construction without consultation...

It should only be massive

What I forgot - with 40 EE there would also be 7,500 more funding... in total then 10,500€ additional costs. Was our first one - on Friday we have another one and then we want to see. Approximately how many should one run?

You should rather invest the 10,500€ additional costs in a larger photovoltaic system. It is certainly more sustainable and economically efficient than the EE at 40 :-)