GROUND-SOURCE HEAT PUMP – EVERYTHING YOU NEED TO KNOW 

A ground-source heat pump taps into the geothermal energy stored in the earth and rock, providing a stable and reliable heat source all year round. The ground maintains a constant temperature between 0 and 9 °C, allowing heat pumps to achieve excellent efficiency regardless of external weather conditions. This ensures consistent performance throughout the year, with low operating costs and a long lifespan for the device. 

There are two main ways to harness heat from the ground: 

• Vertical boreholes (geothermal probes) are vertical shafts between 60 and 200 metres deep, fitted with U-shaped pipe loops to extract heat from deeper soil layers. Each metre of borehole can provide around 40 to 60 W of thermal power, depending largely on the soil composition. The number and depth of boreholes are determined based on the required heating capacity. Each borehole typically requires about 25 m² of land area, and access must be provided for drilling equipment at least 2.5 metres wide. Installation generally takes 1 to 3 days and includes drilling, inserting the probe, and sealing the borehole. 

• Horizontal ground collectors consist of pipes laid at a shallow depth, typically 120 to 170 cm below the surface, in loops of about 100 m each, spaced 0.7 m apart. Each metre of pipe can provide around 10 to 35 W of thermal power, depending on the soil’s composition and moisture content – the wetter the soil, the more heat it yields. This system is more affordable than vertical boreholes but requires a larger area – about 1.5 to 2 times the heated floor area of the building. The land above collectors can be landscaped with grass, but trees with deep roots, buildings, driveways, or pathways must not be placed over them. The soil replenishes its heat through solar energy and rainfall, ensuring the system’s long-term efficiency. 

Thanks to the constant temperature of the ground, ground-source heat pumps are exceptionally efficient. The SCOP (Seasonal Coefficient of Performance) can exceed 5, meaning that for every kilowatt of electricity consumed, the system provides more than 5 kW of thermal energy. This high efficiency translates into low, stable monthly heating costs throughout the year. 

A ground-source heat pump is an excellent option when planning a new build or an energy retrofit. The system is best integrated during the planning phase, as earthworks and system placement are easier and more optimal at that stage. With proper design, you’ll have a reliable, long-term heating system that requires minimal intervention and is virtually maintenance-free. 

• High energy efficiency: Reduced heating costs and consistent performance year-round. 

• Long service life: The system can last up to twice as long as an air-source system. The KRONOTERM ETERA geothermal heat pump is designed with a modular structure, allowing individual modules to be replaced or upgraded, extending the system’s lifespan even further. 

• Minimal maintenance: Designed for long-term, trouble-free operation. 

• Quiet and discreet: With no outdoor unit, the system is very quiet and has no impact on the building’s exterior appearance. 

• Land area for collectors: A house with 120 m² of heated space will require approximately 240–360 m² of land for horizontal collectors. 

• Borehole depth: Typically between 60 and 100 m, depending on the geology of the site. 

• Installation time: Boreholes take 1–3 days to install, while horizontal collector systems may take slightly longer. 

Although the initial investment is higher than with air-source systems, a ground-source system proves more cost-effective over time due to lower operating costs and a longer lifespan. It’s a long-term solution: if the system is ever replaced, the new unit can simply be connected to the existing boreholes, making the investment suitable for multiple generations. 

A ground-source heat pump is an ideal choice for: 

• Homeowners looking for the lowest energy consumption and long-term savings. 

• Investors seeking a sustainable heating and cooling solution. 

• New builds or major renovations where system integration can be optimised from the start. 

• Properties with sufficient land or the possibility of installing boreholes. 

• Environmentally conscious users who want an energy-efficient and eco-friendly solution. 

• Those aiming to secure a heating source for generations to come. 

If you’re considering a ground-source heat pump or want to learn more, we’re happy to help. Contact us to find out whether this solution is the right fit for your home or building.