Which heating technology is suitable if one is sensitive to noise?

*Warning, stupid question* I have no idea about heating technology, but there is one thing that is important to me: the heater must not make disturbing noises afterwards (and I am easily disturbed, e.g. by humming, buzzing, etc.). It would not be located in the basement, but on the living floor. Are there types of heaters that are critical in that respect?

Tip: make sure that the door of the heating room is properly executed and preferably does not face the living area.

Are there types of heating systems that are critical in this regard?

I would say all combustion heaters. However, this can be managed (installation of the boiler on a damping plate/console, Schallex door with drop seal). For heat pumps, the outdoor units are the critical points (which does not mean that everything inside is automatically quiet). Here, one should choose a model where the outdoor unit can be placed freely, in order to select the acoustically best location regardless of the floor plan. With traditional radiators, there may also be flow noises, but this is not an issue with underfloor heating.

A heat pump with brine (deep or surface), walls to the utility room made of 17.5cm solid KS bricks, screed under the heat pump sound-decoupled, as well as the pipes on the wall, door made of solid chipboard, sound insulation strip.... these are all good options to reduce noise.

We have gas! On the ground floor! Separated from the open living area by only a bedroom door! We don't hear it!

Everything with a compressor hums ;-) I can hear the heat pump (very quietly), I hear the refrigerator and the dishwasher. You will never have complete silence in a house (although it is significantly quieter than in all the apartments I have lived in so far)