Which heat pump? Ventilation system / Air-to-water heat pump

For gas, an additional 50-100 EUR electricity costs and approximately 20-30 EUR chimney sweep costs are incurred, as well as the basic fee (for us 195 EUR for gas; 61 EUR for heat pump secondary meter and of course 0 EUR for heat pump on household electricity). The fixed costs for gas are therefore 200-250 EUR higher. In addition, there are the consumption costs.

The investment costs are simply the lowest for that.... although [Luft-Wasser-Wärmepumpe] should be roughly similar to [Gas+ST].

Yes, it is of course true that the data cannot be compared 1:1.

Gas prices are rather 5,x cents here.

I would definitely go for the ground-source heat pump. The drilling for 7000€ is unnecessary – you can lay the ground loop pipes at about 1.5 meters depth with relatively little effort. Just search for "Grabenkollektor". Costs including own work and excavator are around 2000€ - 2500€. This must be offset against the subsidy of 4,500€ (BAFA). Therefore, the extra cost for the ground-source heat pump would only be 4,000 - 4,500€! Over the years, this definitely pays off, especially since electricity prices will continue to rise.

With personal effort, everything is cheaper. Sometimes also more cost-effective. The comparison of trench collector in personal effort vs. air-water heat pump from a professional company is absurd. Then you have to compare installing a Pana entirely by yourself. It also goes faster than a trench collector.

If geothermal energy, then do it right. One drilling for at least 50 - 100 years and that's it.

Oh, trench collector - that doesn't work everywhere, but the card is always gladly just pulled...

It didn't work for us, so a borehole was drilled and everything is great.