Air-to-air heat pump vs air-to-water heat pump vs ring trench collector - differences

We currently turn the underfloor heating up a bit the evening before when we shower the next morning

How long have you been living there and do you really have a heat pump? I believe this heat pump is not running optimally.

As soon as you shower every day instead of every other day, we would keep the bathroom permanently at 23°C, because then a "high low high low" cycle wouldn't be worthwhile with such inertia.

We would then rather heat the bathroom permanently to 23 degrees and the other rooms to 21 degrees. You would probably only have to take that into account in the heating load calculation.

None of the three options allow that. Air-water heat pump and brine-water heat pump due to the inertia of the underfloor heating, and with an air heat pump, you can't just quickly turn the hairdryer higher.

I haven't followed everything, but if you currently live in an older house, you shouldn't compare that. The experience in a modern new building is quite different. If you are still afraid of that, you have to work with additional heaters. Infrared is one option. However, with an infrared mirror, keep in mind that some women who put on makeup in front of the bathroom mirror do not find that very comfortable.

It exists, but is completely uneconomical. Lots of investment that you won't even remotely get back.

At the moment, we still live in an apartment with a regular gas district heating system and radiators. Therefore, we will probably have to adjust.

Can anything be said about the different consumption values of the three heating systems? Logically, this depends on many factors (user behavior; insulation; size of the area to be heated, etc.) ... But there should somehow be a tendency, right?

Is a cooling function of the air-water heat pump any good?

The cooling function generally helps to keep the house a bit cooler during the height of summer. However, this only works if started early and combined with very good shading. You should be able to achieve a 2-3 °C difference this way.
In contrast to a brine-water heat pump, with an air-water heat pump this always means a corresponding energy expenditure.

The biggest problem, however, is the humidity. This makes the temperatures so unpleasant. And the only way to get rid of that in the house is with an air conditioner. We also initially wanted to use the passive cooling of the brine-water heat pump. Now we will probably forego that and, in coordination with our refrigeration technician (who is installing the heat pump for us), lay copper pipes for a possible later installation of an air conditioner.

Can you say anything about the different consumption values of the three heating systems? Logically, this depends on many factors (user behavior; insulation; size of the area to be heated, etc.)... But there should be some kind of tendency, right?

You can't express anything conclusive in numbers. The ground-source heat pump is definitely the most efficient. A lot depends later on planning and design. A poorly designed ground-source heat pump with poorly planned underfloor heating is less efficient than a well-planned air-to-water heat pump.

Very generally, I would say:

An air-to-air heat pump is not worthwhile at KfW55 standard (but please be careful here, the KfW55 seal alone does not provide a direct statement about the insulation standard). What you save on investment there is relatively quickly blown away by consumption. Or to put it another way, you have to have a very, very well-insulated house with a very low heating load for the air-to-air heat pump to be worthwhile despite its lower efficiency. That would be excluded for me from the start.

Ground-source or air-to-water heat pumps are a calculation exercise and a matter of conviction. Basically, the investment for a ground-source heat pump is a good deal higher. On the other hand, there is, of course, the higher efficiency and that with the current subsidies the difference becomes somewhat smaller. You might also have to contribute your own work and enjoy it, and if you use a trench collector, you might get a ground-source heat pump without extra cost.

Thank you! That gives me a good starting point for now...

Can anything be said about the different consumption values of the three heating systems?

Assuming a uniform house built to KFW55 standard and considering the air-to-water heat pump as the standard value at 100%, I estimate the following:

Air-to-water heat pump: 100%
Air-to-air heat pump: 200-300%
Brine-to-water heat pump: 75%

Note, these are not verified values; this is simply my personal assessment.
If anyone has a different opinion or verifiable numbers, I am interested.

Where do my assumptions come from?

Air-to-air heat pump: electricity heats one-to-one
Air-to-water heat pump: 1 kWh electricity delivers 3-4 kWh heat
Brine-to-water heat pump: 1 kWh electricity delivers approx. 4-5 kWh heat

What this also shows is that the smaller the overall energy consumption, the less impact the chosen heat pump has. Thus, an air-to-air heat pump (if at all) only becomes interesting if the total energy consumption for heating is very low (passive house).

When exactly something is worthwhile can only be calculated based on the exact figures of the individual property; everything else can only be a rough estimate.