Trench collector brine-water heat pump or air-water heat pump?

So I can only give you my/our data. We have 190 sqm of usable space and about 150 sqm of living space.

We are still facing the decision of which heating system to choose. I find it really difficult. At first, we were sure that we didn't want an air heat pump because of the "noise." But then our shell builder said why we should spend so much money on geothermal energy when we could get an air-water heat pump + photovoltaic system for the same price and thus recoup the electricity costs.

We will probably still decide on geothermal energy, because I just can't come to terms with such a propeller in the garden and I always find the fans and the humming of the motors unpleasant in new development areas.

Currently, we have offers with the following costs:
- Air heat pump (from Thermia) 16,000 (incl. installation, refrigerant, etc.)
- Geothermal heat pump (from Thermia) 23,000 (incl. earthworks, hoses, connecting, etc.) Sand for backfilling will be added for us
- Pellet heating with firewood backup operation (from Gilles) approx. 23,000

We will not do a DIY trench collector but will have everything done by a provider if at all. That would be too risky for me, especially regarding the connections and joints. According to our provider, for example, the couplings are possible weak points where roots could penetrate and damage the pipes.

Purely mathematically, geothermal will probably only pay off for us in about 15 years…. But as always, it’s also a matter of gut feeling and belief.

If I were in your place, I would seriously take a look at these air heat pumps. Where could they sensibly be located for you, and how much does the "noise" bother you? It would be a shame if the heat pump is audible from the bedroom windows, for example. We have seen it arranged so that the air-water heat pump was next to the front door and behind the pump and behind the house was the garden. So the pump would probably never be heard in the garden and on the terrace.

You sound like you are more inclined toward the air-water heat pump than the brine-water heat pump?
If you prefer an air-water heat pump, that is certainly not a bad way to heat. I would definitely look at the model (noise, performance, maintenance costs) and what the annual performance factor of the air-water heat pump is. There is also a list at Bafa with actual COP figures per outside air temperature.

We currently have offers with the following costs: - Air heat pump (from Thermia) 16,000 (incl. installation, refrigerant etc) - Geothermal heat pump (from Thermia) 23,000 (incl. earthworks, pipes, connections, etc) Sand for backfilling is extra for us - Pellet heating with emergency wood burning (from Gilles) approx. 23,000

What is included in the costs? The entire heating system including underfloor heating?

According to our provider, for example, the couplings are possible weak points where roots can potentially penetrate and destroy the pipes.

This is only possible with a trench collector if the roots of the flowers in the utility room grow into the couplings... In the garden, there is ONLY pipe.

To implement a trench collector, you have to bring some pioneering spirit and a lot of self-initiative; support from HB is rather rare because (almost) no one knows it yet...

Hello,

To implement a trench collector you need some pioneering spirit and a lot of initiative; support from HB is rather rare because (almost) no one knows about it yet...

That is not correct, because it is not that new

Rhenish greetings

Well, the fact that the concept is not new but has been used for decades is okay. But at least in the local market, the trench collector is not particularly widely established. Otherwise, there would be a larger number of professional providers for a trench collector or solid arguments from professional providers against it.

I have (unfortunately) not yet read about any provider that offers it professionally, nor real arguments against it. Because of this, every single builder must each time sell the concept anew both to the HB and partly to the heat pump manufacturer (lower brine concentration, etc.).

Meanwhile, we are leaning again towards a [Sole-Wasser-Wärmepumpe] - have now requested 3 offers - I'm curious. A well driller said 875 net per KW - so around 8000 T€ for us - just the drilling and probe.