Ground-source heat pump
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The choice between air source and ground source energy is one of the big questions for those looking for efficient, sustainable and long-term savings in air conditioning. Both technologies are recognised as renewable in Spanish and European regulations, and in 2025 they will play a leading role in the energy transition of homes and buildings. This guide will help you understand their differences and advantages, and decide which one best suits your needs.
Renewable systems for air conditioning
Both air-source and ground source systems use heat pumps to provide heating, cooling and domestic hot water (DHW). The main difference lies in the energy source: air-source systems extracts heat from the outside air, while ground-source systems extracts it from the ground, where the temperature is more stable throughout the year.
How each system works
- Air-source systems: Uses outside air as an energy source. The heat pump captures heat from the air, even in winter, and transfers it indoors. In summer, the process is reversed to cool the home.
- Ground source systems: It takes advantage of the constant temperature of the ground. A network of buried pipes exchanges heat with the ground, providing heating in winter and cooling in summer, with very stable performance.
Comparison table of performance and efficiency (COP)
| Feature | Air-source energy | Ground-source energy |
|---|---|---|
| Energy source | Outside air | Ground/subsoil |
| Efficiency (average COP) | 3.5 – 4.5 | 4.5 – 5.5 |
| Performance stability | Depends on the outdoor climate | Very stable all year round |
| Initial investment | £8,000–£15,000 | £15,000–£30,000 |
| Annual energy cost (100 m²) | £700–£900 | £500–£700 |
| Maintenance | Low | Very low |
| Service life | 15 – 20 years | 25 – 50 years |
| Space requirements | Outdoor unit | Land for collection |
| Outdoor noise | Medium | Very low |
| Solar integration | Easy | Easy |
Determining factors for selection
Type of property and available land
- Air-source systems: Ideal for flats, semi-detached houses and houses with little outdoor space. Only requires the installation of an outdoor unit, similar to an air conditioner.
- Ground source systems: Requires space for drilling or trenches in the ground. It is more suitable for single-family homes, chalets or buildings with a garden or plot.
Location climate
- Air-source systems: Its efficiency decreases in very cold or extremely hot climates, as it depends on the outside air temperature.
- Ground-source systems: Maintains high and stable performance in any climate, as the ground has a constant temperature throughout the year. It is the best option in areas with harsh winters or extreme summers.
Budget and investment capacity
- Air-source systems: Lower initial investment, quick and easy installation. It is the most accessible option for most homes.
- Ground-source systems: Higher initial investment due to civil engineering work (drilling), but lower energy costs and maintenance in the long term. Payback in 7-10 years thanks to energy savings and available subsidies.
Energy requirements
- Air-source systems: Sufficient for homes with medium or low consumption, or as a complement to other renewable sources.
- Ground-source systems: Recommended for large homes with high heating/cooling demands, or for those seeking maximum savings and long-term stability.
Case studies based on different user profiles
- City flat (80 m², temperate climate): Aerothermal. Quick installation, no major construction work or land required.
- Detached house with plot (200 m², cold climate): Geothermal energy. Greater efficiency, savings in consumption and lower visual and acoustic impact.
- Office building (high demand, intensive use): Geothermal or hybrid. Quick payback due to high energy consumption and the possibility of combining with solar energy.
- Single-family home in a Mediterranean climate: Both options are viable. The choice will depend on the space available and the budget.
Conclusion: which system to choose in 2025?
- Choose Air-source heat pump if you are looking for an efficient, easy-to-install solution with a lower initial investment and your home does not have land for collection.
- Choose Ground-source heat pump if you prioritise maximum efficiency, consumption stability and have space for drilling. It is the best option for extreme climates and high energy demands.
Both technologies are sustainable, eligible for public subsidies and can be integrated with solar energy to maximise savings and energy independence.
Do you have any questions? Consult a professional specialising in renewable energy for a personalised study and use the online calculators to estimate your actual savings.
