Ground-Source Heat Pump Installation

Ground-source heat pump installation is the most efficient and longest-lasting heat pump solution for Latvian homes. The system uses the stable temperature deep in the ground as a heat source year-round, providing high efficiency even in the coldest winters. Although the initial investment is greater than for air source heat pumps, a ground-source system pays off with low operating costs and a service life of several decades. This page covers boreholes and horizontal collectors, project requirements and the installation process.

What is a ground-source heat pump

A ground-source heat pump is a heating system that uses heat stored in the ground as a heat source. In Latvia's climate, the ground at a depth of 1.5–2 meters and deeper maintains a relatively stable temperature of 4–10°C year-round, making it a reliable source even in the coldest months. The heat pump raises this ground heat to a temperature suitable for heating and hot water preparation. Thanks to this stable heat source, a geothermal heat pump achieves the highest seasonal efficiency (SCOP 4–5) of all heat pump types. This means that for every kilowatt-hour of electricity consumed, the system returns 4–5 kWh of heat. It is also the longest-lasting solution — the ground collector can last 50 years or more. A ground-source heat pump system consists of three main parts: the ground collector (boreholes or horizontal pipes) that draws heat from the ground; the heat pump unit itself in the utility room, which raises the refrigerant's temperature; and the indoor heat distribution system — radiators, underfloor heating or a buffer tank with a hot water preparation module. Because the heat source is underground, the system does not depend on outdoor air temperature and maintains high output even on the coldest winter days — this is one of the main reasons homeowners choose a ground-source heat pump for rural or suburban homes with sufficient land area available.

Boreholes or horizontal collectors

A ground-source heat pump system has two main collector types. Vertical boreholes are drilled to a depth of 100–150 meters and filled with refrigerant; they require little land area, but drilling the boreholes is more expensive. Horizontal collectors are laid at a depth of 1.5–2 meters over a larger area and are cheaper, but need a larger share of the plot. Boreholes are better suited to small plots and properties where the land is already landscaped or in use, while horizontal collectors are the more economical choice where a larger area is available. In both cases the project is assessed by a specialist, taking into account the building's heat demand, land characteristics and budget. An advantage of boreholes is also that deeper layers have a higher and more stable temperature, which slightly increases the system's efficiency. Horizontal collector installation is less invasive — it practically doesn't disturb the ground structure, and after laying, the ground surface can be restored to its previous condition. In both variants it's important to ensure that the refrigerant (usually an ethanol or propylene glycol solution) is correctly concentrated and protected against freezing, since repairing or replacing a ground collector after installation is practically impossible without major earthworks.

Land area requirements

Available land area is one of the main factors determining the collector type. A horizontal collector usually needs 2–3 times more area than the home's heated floor area — for example, a 150 m² home needs about 300–450 m² of land for laying the collector. This area can be used again for lawn or garden after installation, but no deep-rooted trees or buildings may be placed on it. Vertical boreholes require only a small area for the borehole location and access for the drilling rig. They are ideal for small plots and densely built-up neighborhoods where larger land areas aren't available.

Permits and project

Ground-source heat pump installation is more construction-intensive than air systems and requires project documentation. The construction project must be approved in line with Latvian building regulations, and depending on the municipality, additional permit documents may be required. Boreholes exceeding 30 meters in depth often require a geological survey, which confirms the ground layer structure and water levels. The geological survey also helps determine the optimal borehole depth and anticipate possible difficulties. A specialist experienced in ground-source heat pump projects will help prepare all the necessary documentation and coordinate it with the relevant authorities, so that installation proceeds without delay.

Installation process

Ground-source heat pump installation takes considerably longer than air systems — usually one to two weeks depending on the collector type and scope. The process includes several sequential stages, from the geological survey to unit startup and testing.

Cost factors

Ground-source heat pump installation represents the largest initial investment of the heat pump types — a typical system for a 100–200 m² home costs from €8,000 to €15,000 or more. The largest cost components are borehole drilling (which can run €3,000–€6,000 depending on depth and number), the heat pump unit itself, the buffer tank, collector pipes and indoor installation work. Despite the high initial investment, a ground-source system offers the lowest operating costs — the high SCOP value and stable heat source mean lower electricity bills over the system's entire lifetime. For detailed cost comparisons and payback calculations, see our heat pump installation price page.

Upkeep and longevity

Ground-source heat pumps stand out for their exceptional longevity and low maintenance needs. The ground collector or borehole, which is not exposed to weather conditions or mechanical damage, can last 50 years or more — this usually outlives the heat pump unit itself, whose service life is 20–25 years. The heat pump unit itself is located indoors, so it is not exposed to frost, wind or UV like the outdoor units of air source heat pumps. Regular preventive maintenance — checking the compressor's condition, the refrigerant composition and the circulation pumps' condition — ensures optimal operation throughout the service life. After the unit is replaced, the existing collector can usually be reused, which reduces the cost of the next unit. This is a significant benefit compared to air systems, where the outdoor unit must be replaced along with the unit. One or two preventive maintenance visits per year are recommended, during which the specialist checks the system pressure, refrigerant density and electrical connections. Major repairs are rare for ground-source heat pumps — most issues that arise are related to circulation pump or control equipment wear, which are relatively cheap components to fix. Operating bills over the service life are also low and stable, as the system is not exposed to fuel price fluctuations or outdoor temperature effects.