A geothermal probe heat pump gets its heat from the ground – via a borehole in which a probe uses the constant temperature of the subsoil. This results in efficient, year-round stable heat, but requires a drilling permit and suitable subsoil. Whether a geothermal probe is possible is decided by the plot: drilling is not permitted everywhere, and not every subsoil is suitable. (As of: July 2026)
Key points in brief
- The geothermal probe uses the constant temperature of the subsoil as a heat source – warmer than the outside air in winter.
- This makes geothermal probe heat pumps efficient and stable over the whole year.
- The prerequisite is a borehole, which must be permitted – in the Canton of Zurich, the responsible authority checks whether drilling is allowed at the location.
- Not every plot is suitable: subsoil, space and protection zones are also deciding factors.
- The higher initial investment is offset by a source that can be used for decades.
How does a geothermal probe heat pump work?
It taps into the heat of the ground. A few metres below the surface, the temperature remains fairly constant all year round – significantly warmer in winter than the cold outside air. This is exactly what makes the ground an attractive heat source: the heat pump has to raise the temperature less because it starts at a higher and more stable level.
Technically, this works via a geothermal probe: a pipe system through which a fluid circulates is lowered into a vertical borehole. It absorbs the heat from the subsoil and brings it to the heat pump, which turns it into heating. Because the source is stable all year round, a geothermal probe heat pump works efficiently even in the depths of winter – unlike an air source heat pump, which has to struggle precisely when it is coldest outside.
The basic comparison of the two systems is in the post air-to-water vs. brine-to-water heat pump. How efficiently a heat pump works overall and what the seasonal performance factor has to do with it is explained in the post on the SPF. The geothermal probe is the way to achieve this efficiency via a particularly good source.
How does the permit process work in the Canton of Zurich?
A geothermal probe borehole requires a permit – that is the crucial difference to the air source heat pump, which manages without a borehole. The reason is the intervention in the subsoil: the responsible cantonal authority checks whether drilling is permitted at the location at all, because not every subsoil and not every zone is approved for it.
A central tool is the cantonal map, which shows where the use of geothermal energy is permitted and where it is not – for example, due to groundwater protection or geological conditions. A serious planning step therefore begins with a look at this map for the specific plot. Only when it is clear that drilling is permitted does the actual application follow.
How the permit procedure for heat pumps is structured in general in the Canton of Zurich – and how the path for geothermal probes differs from that of an air source heat pump – is described in the post on the permit for heat pumps. For the geothermal probe: the procedure is more complex than for an air source heat pump, but at the end there is a particularly good heat source. The specialist company and the drilling company usually take care of the administrative part for you.
Which houses is a geothermal probe suitable for?
For those where the plot plays along – and that is the actual initial question. Beyond the technology, the location decides whether a geothermal probe can even be considered.
Three things must come together:
- Drilling permitted. The plot is not located in a zone where the use of geothermal energy is excluded. A look at the cantonal map clarifies this.
- Space for the borehole. The drilling rig must be able to get onto the property and work there. In very cramped conditions, this can become a hurdle.
- Suitable subsoil. The geological conditions help determine how well the heat can be extracted.
If these requirements are met, the geothermal probe is often the most efficient solution – especially for houses with a higher heat demand, where the stable source pays off over the years. It is an investment with a long horizon: the borehole is a one-off expense, the source is used for decades. How a geothermal probe heat pump then interacts with a solar system is described in the post combine heat pump & photovoltaics.
| Question | Who clarifies it | Significance |
|---|---|---|
| Is drilling permitted? | cantonal map / authority | Knock-out criterion |
| Can the drilling rig get there? | Specialist company / drilling company | Feasibility on site |
| What is the subsoil like? | Specialist company / geology | Efficiency of the source |
| Does the heat demand match? | Specialist company | Economic viability |
Orientation, As of: July 2026. The cantonal specifications and the assessment on site are decisive.
We almost always answer the question about the geothermal probe first with a look at the cantonal map – even before we talk about technology or costs. Because if the plot is not approved for drilling, the rest is moot. In the Zurich region, we experience both: plots where a geothermal probe is clearly the best solution, and those where the zone or space constraints make it impossible – then the path leads to the air source heat pump. The property has the final say when it comes to the geothermal probe. Those who do not shy away from the higher initial effort and meet the requirements get a source that delivers reliably for decades.
Frequently asked questions
Is a geothermal probe more efficient than an air source heat pump?
As a rule, yes, because the heat source in winter is significantly warmer and more stable than the outside air. This leads to a better seasonal performance factor. The advantage is greatest when it is cold outside – exactly when the heat demand is highest. On the other hand, the initial investment is higher.
Why does the geothermal probe need a permit, but the air source heat pump does not?
Because the borehole is an intervention in the subsoil that has to be checked – for example with regard to groundwater protection and geology. The air source heat pump extracts its heat from the outside air and does not need a borehole. With it, other points are in the foreground, such as the noise of the outdoor unit.
Can I drill a geothermal probe on any property?
No. Whether drilling is permitted depends on the zone and the subsoil – this is shown by the cantonal map for your plot. In addition, the drilling rig must physically get onto the property. This location question stands at the beginning of every geothermal probe planning, even before the technology.
Does the ground wear out as a heat source?
With a professional design, the source is designed for long-term operation. Correct dimensioning is important so that no more heat is extracted from the subsoil than it can replenish. This is why the design of the probe belongs in expert hands – it decides on the efficiency over the entire lifespan.
Free initial consultation
Geothermal probe for your house? We will clarify the requirements.
We use the cantonal specifications and the local conditions to check whether a geothermal probe is possible and makes sense at your location – and plan the entire path up to the permit.
Prefer to talk? +41 78 830 83 35
Swissolar-certified specialist company · ESTI installation authorisation (Art. 14 NIV) · in Zurich since 2017 · over 150 systems completed · a personal answer from the specialist company, no call centre
Sources: General principles of geothermal probe heat pumps and use of geothermal energy; cantonal specifications for the drilling permit (Canton of Zurich); empirical values from the planning practice of ecoEn GmbH, Zurich region. The cantonal regulations and the assessment on site are decisive.
Last updated: 9 July 2026 · Author: ecoEn editorial team
