Heating via ventilation with heat pump

And of course it is more expensive to purchase, because it is both a ventilation system and heating in one...

Not necessarily. You completely save on the underfloor heating and all the piping for the heating. If controlled residential ventilation is considered a "given," the exhaust air heat pump has a huge advantage when you look at the investment. One of the reasons why a passive house does not necessarily have to be more expensive than a KFW house. If you "overdo" the insulation, the costs for the heating system (in terms of investment) eventually drop sharply.

I only explained where the sentence that the heating system was expensive to purchase might come from.

I only explained where the sentence that the heating system was expensive to purchase might come from.

Ah okay, I read it differently

Is there anything that supports the air heating? Stove, photovoltaic, solar thermal?

: I have noticed a few times that you equate exhaust air heat pumps with air heating. They are by no means the same. Just meant as a note because it can be easily misunderstood and not to start a fundamental discussion.

I have noticed a few times that you equate exhaust air heat pumps with air heating. This is by no means the same. It is only meant as a hint because it can be quickly misunderstood and is not meant to start a fundamental discussion.

Guilty as charged.

The problem with exhaust air heat pumps is that they cannot supply external energy (apart from the electric auxiliary heater). That means the building must virtually not lose any heat energy, or even gain some passively, e.g. through solar input, for this type of heating to work. It becomes especially critical when the heat from the room air should also suffice. Because to achieve this (as if the perpetual motion machine of warming room air weren’t already difficult enough), it really requires passive houses, zero-energy houses or plus-energy houses. Therefore, no, of course an exhaust air heat pump is not an air heater per se, but when used in the wrong building (which seems to be more the rule than the exception, because the investment is cheap), it becomes one.

Now I don’t know exactly what you mean by "air heating." Commonly, the air-to-air heat pump is understood, meaning energy is taken from (indoor) air and transferred again to air. In my opinion, this is still burdened with the downside of comfort, because having warm air blown around your nose via a fan convector is unpleasant. A surface heating system is much more comfortable.

Even in the wrong building, it won't become one. The AWP, which Viebrockhaus and many others install in their houses, is an air-to-water heat pump. It extracts exhaust air and powers underfloor heating.