Controlled residential ventilation system - decision support

We also decided on the Zehnder ventilation system, allegedly the quietest device on the market. Our neighbors have a very loud ventilation system, which they can only run on the lowest setting; otherwise, you can hear the system 20 meters outside. So in any case, I would make sure that the device is as quiet as possible.
Best regards
Sabine

We also decided on the Zehnder ventilation system, supposedly the quietest unit on the market. Our neighbors have a very loud ventilation system, which they can only run on the lowest setting, otherwise you can hear the system 20 meters away outside. So I would definitely make sure that the unit is as quiet as possible.

Best regards Sabine

Do you know which unit the neighbors have?

What device do the neighbors have, do you know that?

a PLUGGIT.

Best regards
Sabine

a Pluggit.

Best regards
Sabine

That's good to know. Our construction company wanted to sell us a Pluggit. It was always included in the contract. But now we have planned with a Zehnder.

The system is inside and still that loud outside?

Our controlled residential ventilation from Pluggit is outside about 2.5m below the air intake grille at the lowest level (it runs at this level 20 hours a day) not audible. At level 2, you can hear a slight rustling when it is completely quiet.

The exhaust air goes out over the roof and is not audible anywhere.

We now have to make a concrete decision between the Zehnder Comfoair Q350 and the Wolf CWL-300 Excellent. As I already wrote, the Wolf is significantly cheaper.

According to the database of the Passive House Institute, the Zehnder system is significantly quieter: Supply air/exhaust air 52 / 39 dB(A) compared to the Wolf with 67 / 59 dB(A) for supply air / exhaust air. I think those are quite significant differences...

Does anyone know where these large differences in noise emissions come from? After all, both devices only involve air flowing in and out at the wall inlets and outlets including the valves. Of course, the noises from the actual unit in the basement are different, but why these differences at the outlets in the living spaces?

Will the differences in noise emissions be strongly noticeable in everyday life, i.e. if you are not specifically focusing on the ventilation system, what do you think?