ᐅ Costs for Wells or Ground Probes (and Their Advantages)

Hello everyone, we are planning to build soon in the district of Freising and are unsure whether it is better to install a ground-source heat pump with boreholes or a water-to-water heat pump with a well.
What kind of costs (rough estimates) should we expect if a well or boreholes need to be installed?
It would also be helpful to know the advantages and disadvantages of each option.
Our reason for not wanting an air-to-water heat pump is that currently there are no air-to-water units that achieve a seasonal performance factor (SPF) of 4.5 or higher when you input the values into the SPF calculator. We need 4.5 for subsidy eligibility.

Type "5 things you need to know about heat pumps" into your preferred search engine, then check the first results from "your-heat-pump" – everything is clearly explained there.

However, you should also take a closer look at the ring trench collector. This is a type of ground source heat pump where pipes are laid in a ring shape about 1.5–2 meters (5–6.5 feet) deep in the garden. With proper calculation and selection of the heat pump to suit the house’s energy demand, an annual performance factor (seasonal coefficient of performance) of around 4.5 should be achievable. The ring trench collector system also allows for a lot of DIY work, making this option significantly cheaper compared to the relatively high costs of the two wells or deep drilling required for the borehole probes. However, costs vary greatly depending on the location and the availability of local suppliers for such installations.

A trench collector cannot be installed due to the limited size of the plot. Our plot is about 250 sqm (2,690 sq ft). This will likely be too small for a two-family house.

Hello Freisinger. We also built in the Freising district and, due to limited space, had a deep ground collector installed by the geothermal forum.

Its operation is similar to a horizontal trench collector but deeper and more space-efficient. However, it must be said that the fluid temperatures are definitely lower compared to a horizontal trench collector.

If I were you, I would aim for a water-to-water heat pump. Freising is located quite low in the groundwater! The deep drilling was too expensive for us. Quotes were between 12,000 and 15,000 euros. The deep ground collector cost 6,500 euros.

One tip: The Herzog architectural office on Fliederstraße has a water-to-water heat pump installed in their office... you can take a look at it there (I did the same).

Hello Woogl, thanks for the tip. I can definitely try that.

Actually, until yesterday we were still planning on a groundwater heat pump because we thought it would work. According to the heating engineer, it won’t work after all.