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

Which in turn means that the room is not ventilated by the Controlled Residential Ventilation? What is the point of that, if you already have a Controlled Residential Ventilation, then please fully. Just as Steffen described.

The utility room should have an exhaust air connection, meaning it should be connected to the [Kontrollierte-Wohnraumlüftung]. For the door, a drop seal with overflow function would be suitable. I believe I have described this several times here in the forum and it can also be easily found by googling.

To get back to the main topic:

I always have to smile when I read "soundproof door"... Neighbor (who happens to be a custom furniture carpenter) had completely normal solid wood doors in his place. Nothing special, just solid oak doors. That was like a sound barrier^^ The teenage brats in the kids' room were gaming and yelling so loud it was past any hope. We were sitting next door chatting, but you couldn’t understand your own word, they were that loud.
At some point, my neighbor told his sons to close the door.

I thought to myself, what good will that do? With them screaming like that, it’s a lost cause.

But it was actually completely QUIET once the door was closed! As I said, no soundproof door or anything, just mass through real, solid wood, no hollow chamber junk etc.

However, this also requires appropriate door frames and hinges.

I then copied this on my workshop door. They were originally hollow chamber junk doors; when I was milling, it was very loud up there, no chance of cozy TV watching.
So I glued a heavy fiberboard on it and a thin layer of cabinet back panel (was cheaper than veneer^^) on top for the look.
Since I couldn't reinforce the frames and hinges, I simply built a small support roller on the door that takes the weight.
Added a few proper seals and done.

And tadaa, no noise at all in front of the door anymore, it’s absolutely silent, you can’t even hear the compressor now.

What I want to say with this:
It doesn’t have to be specifically "soundproof", a simple, well-adjusted solid door with seals does the same.

Something else is a soundproof door, but it is not more than that, more massive than a normal door and with a seal. You can't just buy any massive door and build a seal on it yourself... firstly, it won't be cheaper and secondly, the soundproof door should look like the other doors visually.

Best regards
Sabine

Our utility room, in which the Tecalor system is installed (identical to the Stiebel), is included in the controlled residential ventilation! And indeed, there is supply air in one corner, exhaust air diagonally opposite! And that is how they planned it. ... is also very convenient for laundry, dries great and the room is never too humid.