New construction according to the 2016 Energy Saving Ordinance no longer possible without a ventilation/exhaust system?

Below 40% humidity at 22 degrees.

A bit dry for my taste. A controlled residential ventilation system with moisture recovery offers more :P

Is indeed unpleasant, irritates the mucous membranes.

Yes, the costs are the main concern. I want to implement a smart home system. Additionally, we have concerns about possible mold growth in the supply lines

This is definitely saving in the wrong place.
You have a risk of mold in the interior rooms if you don't ventilate regularly – and the ventilation system does that for you!

What I find interesting: Here in the forum, the majority are in favor of controlled residential ventilation. During our search for construction companies, we met about 20 different planners, salespeople, master carpenters, ... As far as I can remember, ALL were either clearly against controlled residential ventilation or at least only expressed themselves neutrally because we had clearly communicated from the beginning that we wanted one.

I am still somewhat divided in my opinion.
Against:
- I don't believe in energy savings with such a system, since it is operated electrically around the clock.
- Filters are expensive (unless self-made)
- Every technical device eventually causes problems
- Possibly minimally better spread of sound (but this should be very limited with the central system)
- The air can become too dry

Pro:
- No manual ventilation
- I have severe hay fever and hope for improvement in symptoms
- Better air, pollutants are blown out

The frequently mentioned counterargument of mold I consider nonsense. The air is warm, dry (often even somewhat TOO dry), and in motion.

Most companies wanted between 10 and a staggering 17 thousand euros for it. For a relatively small house. That would definitely not be worth it for me. We get it at wholesale price (<5,000€) and want to install it ourselves. That's why we decided on it.

Contra: - Operating costs are slightly positive or neutral (heat recovery versus electricity and maintenance). - Maintenance effort (filter replacement, filter cleaning) is there, no question. - A system with humidity recovery helps against dry air. Pro: - You really don’t have to ventilate anymore. Net compared to the filter maintenance effort still a time saver. You have to plan a ventilation system and can do a lot wrong with inadequate planning and get into trouble accordingly. In fact, there are many systems in the wild that cause trouble. Usually, it is due to poor planning. For me, this is an explanation why many involved in construction have reservations. But, we are no longer in the early years of controlled residential ventilation in single-family homes. It is actually established, and planning errors can be well avoided today.

I got the impression that some "old masters" just don't feel like dealing with the newfangled stuff. They will build gas with solar until retirement, they know that and that's fine.