Which heating system is currently the best?

Hello,

...I wanted to explicitly point out that at -20° it probably heats purely electrically, so it is not a special achievement of the heat pump to get the house warm, .....

How high the respective performance share of the air heat pump and possibly the heating rod is depends on the characteristic curve of the device in relation to the demand of the building.

Air heat pump B has the higher "own" performance at the design point (-14°C), yet has the worse annual performance factor in the yearly balance.
It is a fundamental mistake to design an air heat pump so that it delivers 100% heating capacity from its "own" power at the design point. Why? Heat generators are mostly operated in part-load range. The COP values determined on the manufacturers' test benches assume that the power produced is actually also used. This is quite legitimate, as they do not know every application case. The planner is responsible for this. He has to select the appropriate device based on the manufacturer’s characteristic curves (COP, heating capacity) that best fits the specific requirements.

What was done wrong in the past (undersizing, insufficient boundary conditions) is nowadays done incorrectly as well according to the motto "more is better," with similarly unpleasant consequences.
Well-planned air heat pump systems can achieve an annual performance factor of approx. 3.5 for heating and hot water, possibly slightly better. Poorly done systems are at 2.3..2.7, at best 3.0. What this means for the operator can be calculated by him with an expected service life of 20..25 years, provided the actual energy demand for heating and hot water is known.

Best regards.

Hi that sounds interesting, can you write that in German? I don't understand anything. So that a layperson understands. It would be great if you could also write about the process, house planner etc., when does it come into play and when is something oversized. How can you tell if you are using a shoddy pump? What do you think about the Proxon plus air heat pump? Is the Proxon comfort technology recommendable?

Thanks and best regards.

It's all pretty straightforward German. Just look at the diagrams, they also explain the matter very clearly.
Pump that delivers too little performance when it's cold = bad, because of the heating element,
Pump that delivers too much performance when it's warmer = bad, excess performance/on-off-on-off.... operation
In both cases, poor annual performance factor.

.... It would be great if you could also write about the process, house planners, etc., when they come into play and when something is oversized.

A house planner or architect is not a trained HVAC planner! Their training is not designed for this at all! A responsible architect will always involve an HVAC planner overall or at least consult them. Unfortunately, this is usually not the case, to the detriment of the client. An oversized heat generator, here an air heat pump, is one that leads to a noticeable deterioration in the annual performance factor and the lifespan of the heat generator.

.... How can one recognize if one is using a botched pump?

For a layperson, this is extremely difficult, if not impossible. Either you decide on a holistic system design of the essential and critical focal points, or you surrender to uncertainty, due to lack of training, to architects or salespeople. Best regards

....Pump that delivers too little power when it is cold = bad, because of the heating element,

Correct! But in the overall energy balance, with exact dimensioning, it makes relatively little difference, as long as it is properly designed!

....Pump that delivers too much power when it is warmer = bad, power surplus/on-off-on-off... operation

Also correct, therefore I preferably recommend a fully modulating air heat pump if an air heat pump proves to be effective overall!

....In both cases poor annual performance factor.

What is a poor annual performance factor? It can only be assessed in the overall context. With 10,000 kWh actual total demand for heating and hot water, it plays a completely different role than with e.g. 3,000 kWh Here opinions then diverge. The higher the actual total demand, the higher the annual performance factor requirements for a heat pump. Quiz question: Who knows the actual demand for heating and hot water?

Best regards

Especially since the actual demand changes over the years (family, children, etc. are not constants). But somehow you have to plan when building new. With renovation, it would be easier, since you know your data from previous years. Nevertheless, the "I'm building 140m^2, which heating system is the best" threads will not die out. Or the indication "KFW70" included, which also does not really give any information about the demand. The annual performance factor is simply interesting as a comparative value, I think, if you know your demand. After all, you can use it to estimate consumption costs and economic efficiency. (Is it worth investing an additional 5k € in a system with an estimated annual performance factor higher by 0.5 at a certain demand?). Ultimately, however, these are all just theories; for a concrete statement you probably need a specific construction project with all the details.