Comparison of geothermal heat pump with LWW pump

There are all-in-one devices for indoor installation. But they're quite bulky. But if you have the space... I think noise shouldn't be a problem with proper decoupling.

I am opting for an outdoor unit. Since I have a "stupid" side anyway (access with pedestrian, vehicle, and utility rights to the rear property), appearance is not so important to me there. You can also hide it with plants (of course, you are not allowed to let them grow directly on it).

For me, gas is still a no-go because there is clearly a political will to phase out all kinds of fossil fuel burners. With the CO2 tax, from 2025 on, about 110 EUR in CO2 tax alone will be due for 10,000 kWh heating consumption. That doesn't sound like much at first, but it will continue to rise. Whether LPG etc. will offset that with just the raw material price is unknown. It is conceivable that the CO2 tax will simply increase even more if consumption does not decrease.

With good arguments, I would not be opposed to an air-to-water heat pump.

There are plenty of good arguments for it. What don't you like about an air-to-water heat pump?

I will soon install two units in a two-family house. Monoblock with a COP of almost 3 at -10 degrees outside temperature (4.9 according to the annual performance factor calculator). What more could you want? Each costs around €5,000 in materials (heat pump/domestic hot water tank and all materials such as pipes, expansion vessel, heat meter, etc.). Then the subsidy is deducted (planned 40% due to KFW 55 renovation).

Our indoor unit has been placed here on a pedestal, directly on the raw floor, even before the screed. I assume this serves for sound insulation (?). The silver plate is still sticking out after the screed has been laid.

I can only repeat, much more relevant than the choice of the heat generator is the correct design of the underfloor heating.

I can change the heat generator without much effort, but not the underfloor heating.

My underfloor heating is designed for a maximum supply temperature of 30, all circuits approximately the same length, maximum length is 2x 90 meters in the bathroom.

This allows me to switch from gas to heat pump easily if it should become necessary.

The house is designed with controlled residential ventilation and heat recovery so that I do not need solar thermal on the roof to comply with the Energy Saving Ordinance.

I can only repeat, much more relevant than the choice of the heat generator is the proper design of the underfloor heating. I can change the heat generator without much effort, but not the underfloor heating.

Full agreement. Changing the underfloor heating pipe spacing from, for example, 15cm to 10cm costs a few hundred euros but brings huge advantages.

The house is designed with controlled residential ventilation and heat recovery so that I do not need solar thermal energy on the roof to comply with the Energy Saving Ordinance.

That sounds really interesting because gas could still be an issue for us, but liquefied gas. So far, I haven't been able to read anything about how to meet the Energy Saving Ordinance without solar thermal energy. Could you provide some details on how to "bypass" this solar requirement or achieve the necessary values?