Integral device Stibel Eltron LWZ 504 with central supply air

You have to make a distinction: In pure ventilation mode, you can't hear it at all in our rooms, not even on level 3, of course you can hear it in the utility room. We only hear it in the rooms when heating is on. Then you hear a rushing sound and a very slight humming, which we do not find disturbing in our very quiet environment.

Thank you for your description. Have you installed any silencers in the ventilation ducts? What type of construction do you have and is the system mounted on a vibration-decoupled plate or simply on the floor? In the basement or on the ground floor?

Our system is installed on a decoupled pedestal. Whether it was absolutely necessary in the basement, no idea, but it certainly doesn't hurt.

In our utility room on the ground floor, decoupled from the rest of the screed. There are 2 sound dampers about 80cm each installed. What do you mean by construction method?

Our LWZ304 also stands on a metal(?) pedestal in the utility room on the ground floor. Silencers are also installed. You can hardly hear anything with the door closed. You also don't hear any noise from the heating through the ventilation. Only a slight rustling from level 2 onwards. But that does not bother at all even in the bedroom next to the bed. I am very satisfied with the choice of the heating so far!

Our THZ 504 is located in the basement, decoupled from the screed on its own pedestal. We also have the silencers for supply and exhaust air between the distributor and the shelf itself. The installer installed it during the shell construction, checked the underfloor heating for tightness, and approved it for the installation of the screed. The screed heating was programmed warm by the installer without ventilation! Commissioning and hydraulic balancing were done during heating. One week after moving in, a technician from Stiebel Eltron came directly and programmed everything with a laptop and measured and adjusted the air inlets and exhaust valves in the rooms. This was precisely calculated in advance at the factory. There was then an instruction. We set the hot water temperature to 43, hyst 2.0, which is plenty for showering, etc. In addition, the water is always moving. I have also already changed the underfloor heating, slope and foot point. If you get involved with the system, you find many parameters to optimize (professional). Current consumption of the entire system in Sept and October, under 200 kWh per month each (heat pump, ventilation, control). KfW55, 165 m2, currently 2 people. House is located at 940m above sea level and it has already snowed.