Geothermal energy has emerged as one of the most solid alternatives for those looking to heat their homes efficiently, respect the environment, and provide a real return on the initial cost. But how much does a geothermal installation really cost? How is the return on investment calculated, and what factors determine the final price? If you're considering abandoning conventional systems and still have doubts about the true outlay involved in heating your home with energy extracted from the ground, here's a complete, up-to-date, and straightforward guide.
In this article, you'll delve into all the details necessary to understand pricing, investment, profitability, payback periods, and key elements to ensure that your decision on whether or not to install geothermal energy is informed and tailored to the Spanish reality, with concrete data, comparisons, and real-life examples.
What is geothermal energy and how does it work?
Geothermal energy harnesses the constant heat beneath the Earth's surface to provide an inexhaustible, clean source of energy year-round. The system is based on the temperature difference between the subsoil and the interior of the home, extracting heat in winter and dissipating it in summer. The process is carried out through a closed circuit of buried pipes (geothermal probes), a geothermal heat pump, which is the heart of the installation, and a heat diffusion system, typically underfloor heating or low-temperature fan coils.
Heat exchange occurs as follows: The probes absorb or release energy depending on the season, A heat transfer fluid transports this energy to the heat pump, which, thanks to a thermodynamic cycle, transforms it into useful energy for air conditioning and domestic hot water. The result is a system that is independent of the outside climate and promises an efficiency of over 400%: for every kWh consumed, up to 4-5 kWh are obtained for air conditioning.
Key components of a geothermal installation
A geothermal installation in a home requires several main elements, each with its own function and associated price:
- Catchment area: It is a network of buried pipes that capture heat from the ground. It can be vertical or horizontal.
- Geothermal heat pump: the engine of the system, which transforms the energy from the subsoil into heating, cooling and hot water.
- Tanks (DHW and inertia): They store hot water and improve efficiency by regulating the number of pump starts.
- Emission system: Underfloor heating, low-temperature radiators or fan coils distribute heat/cold throughout the house.
- Regulation and control: Intelligent systems that manage temperatures, schedules and operating modes to optimize savings.
- Drilling works and technical room: tasks required to install pipes, legalize the installation and connect all elements.
Types of collection systems: vertical and horizontal
There are two major collection systems for domestic geothermal energy:
- Vertical system: It uses deep wells (50 to 150 meters, even deeper in industrial applications). It's ideal in areas with limited land, as it consumes little surface area, and is the most common method in Spain. It allows for a constant temperature throughout the year, regardless of the surface climate.
- Horizontal system: It consists of sections of pipes buried at a shallow depth (usually between 1,5 and 3 meters). It requires much more land, as it requires a plot free of trees, structures, or deep roots. It is simpler and cheaper to install, but its performance can be affected by surface temperature fluctuations, especially in cold climates or with severe frosts.
Depending on the energy demand and available space, the most efficient and cost-effective system is chosen. For example, a 200 m² home with vertical collection typically requires two wells, each about 2–100 meters deep; with horizontal collection, the land must be several times larger than the area to be heated.
How much does it cost to install geothermal energy in a home?
The price of a geothermal installation depends on several factors: the home's surface area and energy demand, type of collection, depth, terrain difficulty, make and model of heat pump, emission system, and the characteristics of the civil engineering work. However, the usual range for a single-family home in Spain (about 180-200 m²) is between 15.000 and 31.000 euros including all works (drilling, materials, machinery and commissioning).
To better break down the price, here's a realistic estimate based on budgets and examples analyzed from various sources:
- Vertical capture: 30-45 € per linear meter of drilling, including probes.
- Horizontal capture: 7-9 € per m² of surface or 250-300 € per kW required.
- Geothermal heat pump: from €10.000 to €15.000, depending on power and brand.
- Tanks (DHW + inertia): between €500 and €2.000 each, depending on capacity and materials.
- Emission system (underfloor heating/cooling): for an average home, between €4.000 and €6.500.
- Regulation and control: from €400 to over €1.000 if advanced home automation systems are integrated.
- Complete installation, commissioning and legalization: around €2.000-3.000.
In general, a 180 m² home with regular demand can have an approximate total cost of € 20.000 to € 28.000Although this is a 25% increase compared to traditional systems, the savings in consumption make up for it in the medium term.
The price per square meter For a geothermal installation, it is usually around €120-135/m², and if underfloor heating is added, it can reach €150-160/m².
Factors that make the final price more or less expensive
Several elements influence whether the final cost increases or decreases:
- Type of terrain and ease of drilling: In hard soils like granite, drilling costs between €22-25/ml; in sandy or silty soils, the figure rises to €30-40/ml, requiring more specific techniques.
- Energy demand: Higher consumption requires more drilling or horizontal intake extension, increasing the cost.
- Space availability: The lack of a garden or land requires vertical wells, which are usually more expensive than horizontal wells.
- Emission system: Installing underfloor heating, the most efficient option, increases the cost, although it reduces energy consumption by up to 75%.
- Accessories and home automation: Smart systems and remote control can add up to between €200 and €400.
- Premium equipment: High-end pumps and advanced accumulators can increase the cost by up to 25%.
It's recommended to request multiple quotes, including all work, equipment, and possible extras, along with a clear breakdown.
Real example of a geothermal installation budget
Let's assume a 180 m² home in Madrid with the following costs:
- Two 100-meter vertical wells: € 8.900
- 12 kW heat pump: € 11.000
- Tanks (DHW + inertia): € 1.800
- Underfloor heating system: € 6.400
- Regulation and control: € 850
- Start-up and legalization: € 610
The total cost would be approximately €29.560 (VAT included, 2024). If underfloor heating is not used, the price drops to approximately €22.000. With subsidies, discounts can be significant.
Maintenance cost and useful life of the geothermal system
Geothermal energy requires less maintenance than gas, diesel, or biomass boilers, as it does not involve combustion or rapid-wear parts.
- Heat pump lifespan: between 20 and 25 years, even longer with regular check-ups.
- Interchanges and collection: They can last between 40 and 50 years without significant problems.
- Annual maintenance cost: between €100 and €200, including periodic check-ups.
Modern systems include remote control, self-diagnosis, and firmware updates, making preventative maintenance easier. They generally require less attention and expense than other conventional systems.
What is the difference between geothermal and aerothermal energy?
Both systems are highly efficient and use renewable energy, but there are key differences that affect cost and experience:
- Power source: Aerothermal energy obtains heat from the outside air, whose temperature varies, especially in winter, while geothermal energy takes advantage of the stable heat of the ground (15-18°C).
- Performance: Geothermal energy maintains a constant efficiency (COP 4-5), compared to aerothermal energy, which can be lower in extreme temperatures.
- Installation price: Aerothermal energy is usually more economical (from €8.000 for a typical home) because it does not require deep drilling, although its long-term savings may be lower.
- Maintenance: Both systems require little maintenance, although aerothermal systems may be more sensitive to environmental conditions and dirt.
- Space and noise: Aerothermal energy requires outdoor space and can generate noise, while geothermal energy is silent and not visible after installation.
The choice depends on the climate, initial budget, available space and savings expectations.
Profitability and payback period: Is it worth investing in geothermal energy?
The high initial cost may seem like a barrier, but the savings in consumption can reduce energy bills by 60-80% compared to electric or gas systems.
- A home with a previous annual expenditure of €2.100 could reduce its bill to less than €600, thanks to geothermal energy.
- The payback period is typically between 7 and 10 years, depending on costs, energy, and current subsidies.
- Once amortized, the net savings can exceed €1.500 annually in heating and hot water alone.
In areas with long winters and high energy prices, geothermal energy is especially cost-effective, increasing the energy value of homes in the medium term.
Main advantages of geothermal air conditioning
Beyond the economic savings, geothermal energy provides benefits such as:
- It does not emit CO2 or pollutants: It is a renewable and emission-neutral energy, suitable for the ecological transition.
- Stable system all year round: It does not depend on the climate or the supply of fossil fuels.
- Silent and invisible: no boilers or chimneys, no emissions or outside noise.
- High durability: Most components have a useful life of more than 20-30 years, minimizing environmental impact.
- Low maintenance: minimal checks and no need to clean filters or change parts annually.
- Versatile applications: heating, cooling, hot water, and even air conditioning of swimming pools or industrial processes.
- Subsidies and tax deductions: programs that cover up to 50% of the investment and profits in the personal income tax return.
Disadvantages and limitations of geothermal energy
Although it has many advantages, geothermal energy is not suitable for everyone:
- High initial investment: Although it recovers in the medium term, it can be an obstacle for some.
- Land requirements: It requires sufficient soil to capture or drill, which can limit its viability.
- Geological limitations: Not all soils allow deep drilling or efficient extraction, requiring prior geotechnical studies.
- Works in existing homes: rehabilitating or modifying facilities increases complexity and cost.
- Lack of awareness and poor implementation: It is not yet a mass technology, which affects prices and competition.
Comparison with other renewable energies: solar, aerothermal and biomass
How does geothermal energy compare to other sustainable energy sources?
- Solar photovoltaic and thermal: lower initial investment, ideal for self-sufficiency in electricity, but lower contribution to air conditioning in winter except in combinations.
- Aerothermal energy: Good value for money in temperate climates; in colder climates, geothermal energy offers greater efficiency and payback.
- Biomass: option in rural areas, although it requires fuel storage and generates smoke emissions, in addition to more maintenance.
Combining geothermal energy with photovoltaic self-consumption is currently the most efficient and cost-effective option for single-family homes, allowing for cost reduction and progress toward sustainability.
Aid and financing for geothermal installations
There are various financing options and grants to facilitate installation:
- European Next Generation Funds and Recovery Plan: up to 50% of the cost, according to cCAA and call.
- Regional and municipal aid: in communities such as Galicia, with specific programs for individuals and neighborhood communities.
- Tax deductions: In some cases, deductions in the personal income tax return for investments in energy efficiency.
- Bank financing and agreements with installers: payments over several years with competitive interest.
Checking the current grants before making a decision can make a significant difference in the final cost.
Frequently Asked Questions About Geothermal Energy, Pricing, and Performance
What minimum surface area do I need to install geothermal energy?
It depends on the system. For vertical systems, a small plot of land or yard is sufficient for access with the machinery. Horizontal systems require sufficient space, equivalent to two to three times the surface area of the home.
Is it profitable in existing homes?
Yes, although the adaptation may incur an additional cost. It's more advisable for comprehensive renovations or those with sufficient space for construction.
How much do you save per year?
Savings can exceed 60-80%, which translates into €1.000-1.600 less in annual bills.
What is its useful life?
The heat pump lasts about 20-25 years; the collection system can last up to 50 years if properly maintained.
How much does it cost to maintain it?
Annual maintenance costs range from €100 to €250, mainly for inspections and checks.
Latest trends and future of geothermal energy in Spain
Innovation in the sector and integration with solar energy position geothermal energy as one of the best alternatives for meet the European Union's climate targets by 2050. Improved technologies, falling costs, and subsidies favor its implementation. The combination with solar panels to generate electricity for the heat pump further reduces operating costs and increases sustainability.
Pilot projects and studies They show savings of over 70% in energy consumption, with amortizations of less than ten years. The trend points to greater acceptance and growth in the residential and business markets, consolidating geothermal energy as a reliable and efficient solution for the future.
