Building application submitted/open detailed questions/looking forward to suggestions

Ah ok, then the statement about the ventilation is correct... that's also my experience... maybe a mix of both systems would be the right thing for you...

I also have completely [Kalksandstein]... I am simply of the opinion... mixing materials, especially masonry, is counterproductive...

Ventilation is currently our "problem child" – this also has to be taken into account for the structural analysis if necessary. I was hoping to find a price range somewhere that would then no longer be audible. According to advertising, that exists too – but so far no one has been able to answer me neutrally whether that is really the case. And are you satisfied so far and do not have any "cold" walls? What wall thickness and insulation do you have?

Yes, satisfied already... We have highly compacted large-format KS stones 15 cm thick and 16 cm EPS insulation... it is warm and stays warm... in summer even too warm in the sleeping areas... but we have since found a solution for that.

And why no central controlled residential ventilation? For the price charged for the decentralized units nowadays, you can already get good central systems...

Ours currently runs at 110 cbm, you don't hear anything... from 200 it only becomes audible but only near the exhaust vents...

I assume it's a matter of belief - I think I prefer to have some control over the pipes. I am also a bit afraid of the construction execution - we have already heard some stories about that. Most recently, our planner advised against it (but I'm not sure if he's just saying that because the statics are more complex). What we looked at were the decentralized ones, which are even more expensive.

So if they are even more expensive, I wouldn’t hesitate for long...

You do have control over the pipes... simply keep the exhaust air ducts as short as possible, then the supply air ducts longer... this way you can clean the exhaust air ducts, which tend to get dirty faster, at any time yourself.

The valves can usually be unscrewed at any time so you can look into the pipes... or clean them then.

Dirt in the pipes after 3 years of continuous operation is practically nonexistent for us... because everything ends up in the filters... the supply air ducts definitely look as if freshly installed... ok, the exhaust air ducts have a slight layer of dust...

We only have spotlights in the kitchen, in the bathrooms, and one above the workspace between the dining and living areas. I don't find them very appealing in the living area. We had considered placing some in the hallway but then decided against it because nice ceiling lights work well there too.

We only have tiles in the hallway, WC, utility room, and bathrooms. We also don't like them in the living space. Especially not because they are simply too cold and hard during transitional seasons, and we like to sit on the floor with the children. So in the living area it will be parquet (including the kitchen), and upstairs throughout (except bathrooms) we are currently getting quotes and advice. We don't want to spend too much since it's 120 sqm of flooring alone upstairs. So max €25-30/sqm. Currently, high-quality laminate and natural cork are options. Although I actually don't want laminate (loud and cold). My husband, on the other hand, isn't so keen on the cork look. Maybe we'll also find an affordable parquet for upstairs. With children, I find tiles absolutely unsuitable. Or who likes sitting on a tiled floor?