Ventilation in new buildings (central vs. decentralized), noise disturbance

Well - every system needs to be kept clean and maintained. (Filter replacement, cleaning/disinfection...) The bigger, more expensive, and more complex it is, the higher the follow-up costs. For one person (hay fever sufferer) it's worth it, for another (ventilating rural resident) it's not.

Once a month vacuum it, once a year change the coarse filter (costs a euro or two) and replace the fine filter if needed (about €25, so far once in two years).
So far, nothing more is necessary - follow-up costs are therefore not an argument against a central controlled residential ventilation system.
Do the decentralized systems have no filters then? That would be a big disadvantage - I don't want to forcibly bring pollen and dust from outside into the house.

If that's all, then the systems probably don't differ much. Until now, I assumed that a service technician had to come by every one or two years.

They are very different...the operating principles are completely different. And with that, also the comfort for the user.

I meant, they don't differ much in terms of cleaning effort. That they are still very different systems is clear. And one thing is also clear: the OP knows as much as before his question!

In a new building, like the one the [TE] is planning, I would recommend a central controlled residential ventilation system with heat recovery. The reasons – among others, comfort – were mentioned here, I can personally confirm them.

I would advise the [TE] to choose a system capable of increasing humidity in winter. The system I have does not have this feature; the air becomes quite dry.

Apart from that:
- With a properly dimensioned system of this type, the air is nice and fresh and pleasant. In show homes, it is often experienced: windows are open, naturally there is constant coming and going. Such systems bring no noticeable benefit... how could they?

- The cleaning effort is minimal. I clean the main filters once a year and the exhaust air filters in the ceilings 3-4 times a year (work effort = Mickey-Mouse, I can even manage this after hip surgery).

- Outside the cold months, the system has the advantage that allergens/pollen enter the house less. However, this is unrealistic – even we have windows open, system off. Also, features like summer bypass: are overrated – hardly useful, because it is *not* air conditioning (unless the system includes that, which also exists). Furthermore, you can set the system to "exhaust air only," so a certain amount of (cold/cooler at night) fresh air also flows in through tilted windows......

- Draft and noise are no problem in my opinion; given the necessary air exchange rates, the flow speeds at the chosen cross-sections are minimal. Moreover, inlets are best placed in front of windows... not directly at beds, under tables, and the like. A case for good planning, correct dimensioning, and setting. We have that – works very well.

As I already said elsewhere here, I would never build again without ventilation if I had to build again. I am enthusiastic about the system; we mitigate the negative point "dryness in winter" to a tolerable level with "hanging laundry" and "humidifier."

In winter (so generally here in Velbert always, laugh, a little insider because of the weather thread just now), more precisely when you do not want to open a window to avoid heating the garden, an overall very good climate is created in the house, the complete air is exchanged every approx. 2 hours, with heat recovery only few losses occur (! there are NO GAINS as some think, it is just cheaper to ventilate this way than with open windows).

Best regards
Thorsten

Are the decentralized systems without filters? That would be a big downside - I don't want to forcibly bring pollen and dust from outside into the house.

Of course, I can't speak for all decentralized systems here. With ours, you can choose whether to use dust filters or pollen filters (each available in different classes). Our system prompts us about every quarter to replace the filter. The pollen filters definitely need to be replaced then – the dust filters can also be washed by hand or in the washing machine (in a bag). So far, we have only had dust filters, which we washed three times and replaced the fourth time. Ten dust filters cost about 30 euros, if I remember correctly (we need them for 6 fans when replacing). Once the replacement supply is used up, next time we will buy one or two square meters of filter fleece and cut the filters ourselves from it. I think that will be even cheaper.

Although my wife is allergic, so far we did not have to resort to pollen filters.