Is a soundproof door necessary in the utility room? Experiences?

so our machine is quiet, even at 1600 revolutions. Quality and weight make a big difference...

You can get a Miele for 1-2k euros and the same again for the dryer, and then it's the compressor of the heat pump, or you don't take any risk and pay 200 euros for the sk2.

If I understand the OP correctly, it's not about saving the 200€, but whether the controlled residential ventilation still works if he installs this door.

He asks both. But why should the controlled residential ventilation not work?

Because this door apparently includes a continuous seal if I understood correctly. And if the door is left slightly shorter at the bottom to allow air to overflow from the hallway to the utility room, then this conflicts. Ergo, either you shorten it so far that the seal at the bottom no longer functions or you don’t, but then the overflow doesn't work.

By the way, we have both a washing machine and a dryer new from Miele and yet you can hear these appliances (and we do not have the cheapest models), and in my opinion, a soundproof door definitely makes sense. We also have a controlled residential ventilation system and the sealing certainly hinders the air from flowing through, however, someone very often goes into the utility room here, so I don’t see any problems with that; the door is not closed all day. I would have the soundproof door installed again anytime, it’s amazing how much quieter it is because of it.

Best regards
Sabine