Ground source system: how to harness underground heat for climate control in your home
Harness the ground’s heat for climate control in your property. Discover how it works, what types are available, which suits you best, and what its advantages are.
Can you imagine using the constant temperature beneath your feet to climate control your home throughout the year? It isn’t science fiction, nor a promise for the future: it’s what ground source technology makes possible. This renewable energy source is becoming increasingly popular in climate control due to its efficiency, low environmental impact, and ability to provide heating, cooling, and domestic hot water from a single system.
What is a ground source system?
Ground source technology is a renewable energy source that harnesses the heat stored beneath the earth’s surface. Although we commonly associate it with volcanoes or hot springs, it can actually be used in more everyday settings. Just a few metres below the surface, the ground temperature remains fairly stable all year round, typically between 10 and 16 °C in most regions. It’s this thermal stability that forms the basis for efficient indoor climate control.
How does a ground source system work?
The key is the ground source heat pump, which extracts heat from the ground during winter to warm your home and reverses the process in summer to cool it, working similarly to an air-to-air heat pump but exchanging heat with the ground rather than the outside air.
The system consists of three essential components:
The buried circuit (ground heat exchanger): This can be installed horizontally or vertically and contains a fluid that circulates through pipes buried underground. This fluid absorbs or releases heat from the ground, depending on the season.
The ground source heat pump: This transfers heat between the fluid in the buried circuit and the water in the property’s internal circuit, providing heating, cooling, and domestic hot water (DHW).
The indoor distribution system: Underfloor heating, low-temperature radiators, fan coils... There is a wide range of options that can be tailored to suit the specific characteristics of each home.
Types of ground source systems
The choice of installation type depends on factors such as available space, ground conditions, energy consumption, and budget. The following are the most common:
1. Horizontal ground loop
This involves burying pipes at a shallow depth (between 1 and 2 metres), making use of a large area of land. This solution is more cost-effective than vertical heat collection but requires ample free space, making it most suitable for detached houses with gardens.
An efficient climate control solution is the Daikin Altherma 3 GEO, a ground source heat pump designed to provide heating, cooling, and domestic hot water with outstanding performance all year round. It operates quietly and integrates seamlessly into new homes or renovations, offering various emitter options such as underfloor heating or fan coils.
2. Vertical ground loop
This is achieved through deep boreholes (between 50 and 150 metres) and is ideal for small plots or urban areas. Although the initial investment is higher, efficiency improves as temperatures remain more stable at greater depths.
3. Groundwater abstraction
Water can serve as a heat source whenever an aquifer is accessible. Although highly efficient, this option requires specific permits and a comprehensive hydrogeological survey.
Maintenance: straightforward and long lasting
One major advantage of ground source systems is that they require very little maintenance. Because the ground circuit is buried, it experiences no wear and can last for over 50 years without issues. The heat pump, like any other climate control system, requires regular inspections, although these are less intensive than for other systems.
Simply inspect the exchanger annually, check the thermal fluid, and perform a basic clean of the system. With no burners, fumes, or fuel tanks involved, maintenance is much simpler and risks are minimised.
Benefits of ground source systems
High energy efficiency
Ground source systems can achieve coefficients of performance (COP) above 4, meaning that they generate over 4 kWh of thermal energy for every kWh of electricity consumed. In other words, lots of energy with little outlay.
Clean, renewable energy
These systems do not emit CO₂ or other polluting gases when operating. What's more, they don't rely on fossil fuels, which helps achieve energy independence and makes homes more environmentally friendly.
Comfort all year round
They provide heating, cooling, and hot water within a single system, operating quietly and steadily without creating air currents. Combined with underfloor heating, they deliver maximum thermal comfort.
Long-term savings
Although the initial investment may be higher than other systems, low energy consumption and reduced maintenance costs offer an attractive payback over the medium to long term.
Discretion and durability
Once installed, the system is fully concealed, occupies no space inside or on external walls, and boasts a very long lifespan, particularly the buried circuit.
And the drawbacks?
Despite the many advantages, there are a few points to consider before opting for ground source heating:
High initial investment
Installation costs are higher than for other conventional systems, especially if vertical drilling is required. However, grants, and subsidies for renewable energy installations can help reduce this financial barrier.
Need for building work
Installing a ground source system involves drilling or earthworks, making it easier to incorporate into new builds or major renovations. That said, with careful planning, it can also be retrofitted to existing properties.
Preliminary study required
A geotechnical study and ground analysis are essential to ensure the system’s viability and efficiency. Although this step adds to project time and cost, it's crucial for success.
Is a ground source system right for you?
Whether you're embarking on a new build or renovating your current home, ground source technology offers an efficient, sustainable, future-proof solution for your climate control needs. Although the initial investment may be higher, the stability, comfort, and energy savings it provides over time make it an increasingly popular choice for those seeking high-performance climate control with minimal environmental impact.
At Daikin, we have been developing innovative climate control solutions based on renewable energy for many years. If you’d like to know more about integrating a ground source system into your home, be sure to get in touch with our experts. We’ll help you find the solution that best suits your needs.