Is it still reasonable to build according to the Energy Saving Ordinance 2009?

I think he is talking about the property. In my opinion, you don't save anything on the house, you might even pay extra, that's why I also say he should think it over.

Our house easily meets KfW70 standards, according to the figures it is around KfW59/60, so it only requires 59/60% of the reference value. We also decided right away on a Pluggit ventilation system, triple-glazed windows with WD roller shutters and very good frames, underfloor heating, etc.

Especially with the ventilation system, it was important to us to have it installed. If the requirements inevitably increase, we can have a complete WDV insulation installed around the house in 20-30 years. For that, controlled residential ventilation (air exchange) is absolutely necessary. We already have this.

Hello,

as already suspected above, the price differences referred to the land. In terms of pure construction costs, a single-family house is only slightly more expensive (at least according to the offers we have so far). I now also think it should definitely be triple glazing and underfloor heating. In this respect, the first property (which is why I started the thread) is now out of the running. It would simply become too expensive...

But now we already have two more plots of land that we like quite a lot...

What does it look like, is the neighbor already building? Because of that, we had to orient ourselves to the neighbor's house. It cost us more than a single-family house. Underfloor heating definitely, you can only retrofit that with great difficulty later, windows and ventilation are easier to retrofit!