Ventilation system in single-family house without effect = planning error?

Thank you, but I mean the device with which you measure and record the air quality and humidity... ;)

Oh, sorry. I must have misunderstood :p I am using this here: Netatmo air quality monitor

I wanted to give a little interim feedback: Regarding the rise and fall of air quality on the measuring device, I would say that the system is doing what it is supposed to do: When the system is turned off overnight, the CO2 value rises to over 1500 ppm. The maximum value was around 1800 ppm. Now, with the system running at about 190m³/h, the value dropped to 650 within about an hour -> trend continuing downward. So, it probably isn't due to that, right?

Here’s something to make you smile: I borrowed a fog machine from the neighbor, set it up in the bathroom, and just fogged the entire room: The fog was completely gone within an hour. That sounds pretty okay to me at first. But I wouldn’t necessarily want to repeat that in bedrooms ;-)

An appointment with a Wolf field service technician is scheduled for 18.2. I’m curious about that, since the issues of dirt and noise are still present. My site manager also brought in a friendly installer, and he wants to have another look once the "snow chaos" in this area has been cleared.

What worries me a bit, however, is that both our (gas condensing) heating system and the ventilation system are currently consuming about 600-800W of electricity at the low temperatures (-8°C). Of course, no one tells you that before you buy. :(

Your wolf-controlled ventilation system for living spaces normally has a preheating coil that heats the very cold outside air enough to prevent the heat exchanger from freezing.

... What worries me a bit, however, is that both our (gas condensing) heating system and the ventilation system currently consume about 600-800W of electricity at the low temperatures (-8°C). Of course, no one tells you that before buying. :(

The gas condensing boiler also only requires a bit more electricity than usual because the pump has more work to do (circulation, underfloor heating). Do you have separate values for the gas boiler and controlled residential ventilation regarding electricity consumption? I think is right about the preheating coil ...

The gas boiler should actually not consume more than usual, at most a couple of percent. In the [Kontrollierte-Wohnraumlüftung], the preheating coil is certainly to blame.