Ground-source heat pumpHeat from the ground.

A ground-source heat pump uses the heat of the ground. One or more pipes reach down into the subsoil. A fluid picks up heat there and carries it to the heat pump in the house. From a few metres down, the temperature stays almost constant all year.

That is why it works especially evenly in winter, just when the outside air is cold. Together with a solar system, it reduces the electricity you draw from the grid.

You will find an overview of all systems under heat pump. This page is about the borehole: when it is possible, what it costs and how the drilling works.

How does a ground-source heat pump work?

A probe is placed in a borehole: a closed pipe loop filled with water and antifreeze. The mixture picks up heat from the ground. The heat pump lifts it to the temperature level of your heating system.

Because the source temperature is constant, the seasonal performance factor (SPF, JAZ) is higher than with air-to-water units. Typical values are around 4 to 5. So for every kilowatt-hour of electricity, you get correspondingly more heat. Electricity demand falls, and so does the need for winter electricity, which the solar system cannot supply.

May I drill a borehole? Permit and water protection

Boreholes need a permit. Drilling reaches into the ground and can endanger groundwater. So the canton decides, following the water protection rules.

• Not allowed everywhere: In groundwater protection zones and areas, boreholes are usually banned or subject to conditions.
• Cantonal maps: The cantons show online where boreholes are allowed, allowed with conditions or ruled out.
• Boundary distances: Minimum distances to neighbouring plots, buildings and pipes must be kept.
• The permit takes time: Depending on the canton, it takes weeks to months. This is the part that affects planning most.

We check the plot before the quote and tell you openly whether a borehole is possible. If not, we show you the alternative, usually an air-to-water heat pump.

How does the drilling work?

A specialist drilling firm does the drilling. We coordinate it and remain your contact.

1. Drilling rig: It drives onto the property and is set up.
2. Drilling: Usually one to two days per borehole.
3. Placing and backfilling the probe: The borehole is sealed.
4. Pressure test and connection: The pipes are routed to the house and tested.
5. Documentation: The drilling firm supplies the canton with the required documents.

There is noise, mud and a machine on your property. The garden is restored afterwards. Expect the area around the drilling site to be unusable for a few days.

Ground-source or air: which suits better?

	Ground-source heat pump	Air-to-water heat pump
Investment	higher	lower
Efficiency in winter	high, steady	drops with the cold
Noise outdoors	none	may matter, depending on the site
Permit	always needed, not possible everywhere	usually simpler
Space	access for the drilling rig	standing area for the unit
Older building	good, even with a higher flow temperature	good, once the flow temperature is checked

Neither option is always the right one. For many houses, air-to-water is more economical. For larger buildings, high heat demand, or where noise is an issue, the borehole is worthwhile. We calculate both for your house.

Ground-source heat pump with solar system

The borehole reduces electricity demand in winter. The solar system covers part of it, mainly in the shoulder seasons. Together they reduce what you draw from the grid.

• Hot water can be heated during sunny hours.
• The controls coordinate the heat pump and the solar system.
• A battery storage unit shifts solar power into the evening.
• Less winter electricity from the grid means less dependence on the electricity price.

Who benefits from a borehole?

A borehole pays off mainly in these cases:

• Higher heat demand: In large houses and apartment buildings, the higher efficiency has a bigger effect.
• Older building with a higher flow temperature: The steady source temperature helps here.
• Little space or noise problems outdoors: There is no outdoor unit.
• Long-term planning: The probe itself lasts many decades. The heat pump can be replaced later without drilling again.

It is not suitable if water protection rules ban the drilling, if there is no access for the drilling rig, or if the cost is too high in relation to the heat demand. We clarify this before the quote.

How is the borehole sized?

The length of the probes depends on the heat demand of the house and on the ground. Probes that are too short cool the ground down, and efficiency drops. Probes that are too long cost more than necessary.

So we calculate the heat demand carefully before the drilling firm sets the length. For larger systems, several probes with spacing between them are needed. Keeping to the boundary distances is also part of the planning.

What does a ground-source heat pump cost?

For a single-family home, the total cost is roughly CHF 45,000 to 70,000, before subsidies. This is a guide, not a price. The drilling makes up a large part of it.

What determines the price:

• Metres drilled: More heating output means more probe length.
• Ground: Hard rock is drilled more slowly than loose ground.
• Access: Narrow access roads make the drilling longer and more expensive.
• Removal: Oil tank, chimney and boiler.
• Heating system and electrics: Depending on condition, adjustments are needed.

You receive the binding quote within 72 hours of the site visit, covering the drilling, subsidies and running costs.

Subsidies

There are subsidies for ground-source heat pumps too, mostly through the cantonal buildings programme, in some cases also from communes and energy suppliers. The conditions differ by canton.

Often the application must be submitted before work starts. We submit the subsidy application for replacing your heating system as part of the service. On request, we pre-finance the subsidies.

How your project runs

1. Enquiry and site visit: We check the house, heating, plot and access. Free of charge.
2. Water protection check: Is drilling allowed at your address?
3. Quote within 72 hours: binding.
4. Permit and subsidy application: We submit both.
5. Drilling: by the drilling firm, coordinated by us.
6. Installation: Heat pump, storage tank, hydraulics, electrics, removal of the old heating.
7. Commissioning: We set everything up and explain how to use it.

From planning to commissioning, everything stays in one hand.

Ground-source heat pump in your region

Our locations are in Zumikon ZH and Lachen SZ. We work across German-speaking Switzerland. The cantons regulate differently where boreholes are allowed. We know the maps and procedures and tell you at the site visit what applies at your address.