Different Heating Concepts Compared

you are talking about a completely different system ;-)

Then define your system properly, instead of just linking an advertising table in #13 ;) The Proxon and comparable systems are now offered as standard by many prefabricated house manufacturers because they require little effort. And if the customer does not want it, you can immediately sell underfloor heating and a heat pump as an expensive upgrade.

Nice discussion, I would, however, appreciate it if someone would say:

The house xyz needs x kWh of electricity for heating per year with an air-to-air heat pump / with air-to-water and underfloor heating x kWh of electricity for heating per year.
How big is the difference? Are we talking about 5% less due to an elaborate underfloor heating system, or rather 10% or more? Compared to the modern split air conditioner, e.g. Panasonic Etherea

Nobody can answer that for you precisely, as there are countless factors. Even just how well your heating system is adjusted can have a huge impact on consumption. How warm you like it. How cold it is outside. Any general statement about electricity consumption would be nonsense.

Just imagine, the heating engineer installs a perfectly tuned air-water heat pump and the owner first sets the flow temperature to 60 degrees because he heard somewhere that something astral happens in the pipes below that. It is clear that the electricity costs then skyrocket. The same goes for any other concept.

That is nonsense, just because it is modernly insulated with underfloor heating, it does not at all prevent biological life. I’ll summarize:

Drinking water may contain germs and does contain them. In the public network, because it is below 20 degrees, the reproduction is unproblematically low. At 60 degrees in the water storage tank, growth is prevented. At 70 degrees in the water storage tank, they are killed.

Heating up to 60 degrees every few days is absolute nonsense, it only temporarily reduces Legionella growth. You have to go to 70 degrees so that they die.

If you don’t go to 60 degrees as a standard, and don’t want to regularly go to 70 degrees, you should set it as cold as possible and still have to live with the risk.

This topic kills the air pump in winter. In winter, I hardly get 50 degrees with a solar system. Without gas or anything else as support for the solarspeicher it is a breeding ground after a few winter months. As we know, 60 degrees would be too much for the air pump, so why prepare hot water with it at all?

Let's summarize:
Legionella in single-family homes are not a problem in practice, no matter the temperature. Why? Because Legionella live in STANDING water. In a typical single-family home, regular water use is common practice; after returning from vacation, you may need to let a few liters run just in case.

If you use water, you don't have to worry about Legionella growth.

By the way, every modern air-to-water heat pump achieves 60 degrees Celsius of hot water temperature; in winter (down to -15 degrees) 55 degrees should not be fallen below. When using the heating element for the Legionella program, it is always 60 degrees.

Oh yes, the conclusion of the UBA analysis should not be omitted:


And maybe also consider it more differentiated: