Is a ventilation system cost-effective? Does it save money?

Thank you all for the many responses. I already thought that the payback period of 10 years is quite optimistic. But if the craftsman means the cleanliness and dust deposits in my lungs, he is probably right. So it looks like the investment somehow financially pays off over time and also has positive side effects that are not yet quantifiable. So why doesn’t everyone do it then? Sounds like a great investment...

Because there are people (like us) who love to keep windows and doors open as soon as the weather allows it. Because it enlarges the living space, gives freedom and openness. Who love to sleep with the window open. Not just because of the fresh air, but also because of the birds and other sounds of nature, e.g. the croaking of frogs in our pond. Because it costs money to purchase (which must be available or financed) and space. Because for people like us it would probably never pay off. Because it sometimes causes air that is too dry.

That means, however, that in summer you always have to keep all windows and doors closed. That would be unimaginable for us.

Of course, a lot of air comes into the house in summer - through the ventilation system. Why should I have all the windows and doors open? There is no (rational) reason for that. If you feel better with open doors and windows, then do that.

but also because of the birds and other sounds of nature, e.g. the croaking of the frogs in our pond.

Another reason to have a ventilation system. Who seriously wants to listen to the croaking frogs all night because they can't fall asleep ==> unfortunately, that is the normal case.

Because it costs money to purchase

Yes.

takes up space

Not really, certainly not decentralized.

Because it would probably never pay off for people like us

It hardly if ever does with new buildings anyway.

Because it sometimes causes air that is too dry.

Depends on the respective model. But it’s not much different than without a system – physics can’t be circumvented.

But as I said, it is individual. Pro open windows is emotional. Pro controlled residential ventilation is rational with many advantages.

Of course, in summer a lot of air comes into the house - through the ventilation system. Why should I have all the windows and doors open? There is no (rational) reason for that. If you feel better with open doors and windows, then do that.

Another reason to have a ventilation system. Who seriously wants to listen to the croaking frogs all night because they can’t fall asleep ==> unfortunately, that is the normal case.

Not really, definitely not decentralized.

It hardly happens at all in new buildings anyway.

Depends on the respective model. But it’s not much different than without a system – physics can’t be bypassed.

But as I said, it’s individual. Pro open windows is emotional. Pro controlled residential ventilation is rational with many advantages.

Especially the feel-good factor should be relatively high in a house, at least for us. And many decisions about building a house are not rational but based on the feel-good factor. A shower, for example, is more sensible than a bathtub for rational reasons. I am now sitting in the living room with the terrace door open (it’s still too cold outside), listening to the birds and the trickling waterfall at the pond. I wouldn’t want to miss that. By the way, it is far enough away from the bedroom, so we can sleep wonderfully despite the frogs. But that is subjective again. Decentralized ventilation systems have already been practically ruled out as not particularly great for new buildings. And a central ventilation system requires about 1 sqm of space. And no, when airing out you only bring in dry air temporarily, with the system it’s permanent. Therefore, the problem of dry air is intensified with a system.

You can minimize the problem of dry air with ventilation systems that have enthalpy heat exchangers.
Opening windows is also possible with a ventilation system.
With us, windows and doors are also open despite the ventilation system – if we want to, not because we have to.
Who ventilates manually enough, especially in winter? Especially for those sensitive to cold, you often notice even in old houses – it should be ventilated. At least twice for 5-10 minutes of shock ventilation and not just the window in the guest bathroom tilted, when at home even more often – very few do this.

And I also love hearing the birds chirping in bed in the morning, and when the church bell sounds loudly, it means quickly get out of bed. With us, despite the ventilation system, the bedroom window is tilted or open – if there isn’t another party going on three houses away.

But as I said, it is individual. Per open window is emotional. Per controlled residential ventilation is rational with many advantages.

This interpretation of "rational" is completely detached from reality. In this logic, it is rational not to have children, since rationally considered, they have measurable disadvantages: they cost a huge amount of time and money, create mess and polluted air. Completely inefficient. What is rational is measured by the achievement of goals. Different goals sometimes require different solutions. It is rational, when designing and building your own house, to do so in a way that best supports your own life priorities. Different technologies can be appropriate for this. Framework conditions are to be taken into account.

You can minimize the problem of dry air with ventilation systems that have an enthalpy heat exchanger.
Opening windows is also possible with a ventilation system.
In our case, windows and doors are open despite the ventilation system – if we want to, but we don’t have to.
Who ventilates manually enough in winter? Especially for those sensitive to cold, even in old houses you often notice – it should be ventilated sometimes. At least twice with shock ventilation for 5-10 minutes and not the window in the guest WC tilted; if one is at home, even more often – very few do this.

And I also love hearing the chirping of birds in bed in the morning, and when the church bells ring loudly it means get out of bed quickly. Despite the ventilation system, the bedroom window is tilted or open – unless there is a party three houses away again.

Sure, but the heat exchanger costs extra.
In our case, after almost 4 years, the ventilation routine has worked well: once in the morning, go around, raise the shutters, open windows, after a few minutes close again. Opposite in the evening. During the day, we open the doors so often (cat in and out, dog going for a walk, to the garage, to the waste area, to the shed, leaving…) that this is completely sufficient, maybe not in theory but in practice.
I don’t want to say anything against controlled residential ventilation. It was just asked why people also build houses without controlled residential ventilation.