LWZ 8 CS Premium combi made of air-water heat pump, controlled residential ventilation and hot water storage tank

No, of course not. It is an extra. Of course, most have it "by default". But who knows what you get there.

So it is clearly recommended, this bypass?

The question is also how the efficiency difference is in the [WRG]?

The question is also what is the efficiency difference in heat recovery?

Hm... according to the data on the Stiebel Eltron website, there is only the specification "heat provision level up to 90%." I couldn't find anything more. Whether that means the controlled residential ventilation, I don't know either.

90% wouldn't be more than with a normal controlled residential ventilation, would it? That would be a bit disappointing, especially since it was said that the exhaust air of the controlled residential ventilation is still used by the air-water heat pump and thus more energy is recovered there...

90% wouldn’t be more than with a normal controlled residential ventilation system, right? That would be a bit disappointing, especially since it was said that the exhaust air from the controlled residential ventilation system is also used by the air-water heat pump, thereby recovering even more energy there...

I don’t know what you imagine, but the integral unit is exactly the three devices combined in one housing. So you have a separate controlled residential ventilation system, a separate heat pump, and a hot water storage neatly packaged.

Accordingly, the values only differ to a limited extent from those of the three separate devices.

We have the Tecalor thz 504 which is identical to the lwz 504 from Stiebel. The device works flawlessly...

We have the Tecalor THZ 504, which is identical to the LWZ 504 from Stiebel. The device works flawlessly...

Can you write a bit more? What heating load do you have? What supply and return temperatures? What annual performance factor? Subsidies?