What is a groundwater heat pump?
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Stefano Fonseca ist Ingenieur für Energie und Umwelt mit über sechs Jahren Erfahrung in der technischen Gebäudeausrüstung (TGA). Er kombiniert technisches Fachwissen mit einer Leidenschaft für verständliche Kommunikation. Seit mehr als fünf Jahren schreibt er als freiberuflicher Redakteur über erneuerbare Energien und nachhaltiges Wohnen, insbesondere über Photovoltaik und Wärmepumpen.
Deep underground, there is a reliable heat source that offers almost constant temperatures all year round: groundwater. A groundwater heat pump uses this energy to heat buildings. Find out everything you need to know about groundwater heat pumps here.
What is a groundwater heat pump?
A groundwater heat pump is a heating system that uses groundwater as a heat source. Because the groundwater temperatures are constant all year round, it is the most efficient type of heat pump. As a result, it is particularly energy-efficient and represents a sustainable alternative to conventional heating systems.
How does a groundwater heat pump work?
A groundwater heat pump extracts heat from the groundwater via a well system and transfers it to the heating system via a heat exchanger. There, it transfers its heat to a refrigerant, which evaporates even at low temperatures. A compressor then increases the pressure of the gaseous refrigerant, causing the temperature to rise. The heat obtained is then transferred to the heating system via a second heat exchanger. The refrigerant then flows through an expansion valve and regenerates. This closed circuit ensures efficient and sustainable heat generation.
In order for a groundwater heat pump to work efficiently, it requires a Brunnenanlage with two wells: the extraction well and the absorption well. The extraction well removes the groundwater and directs it to the heat pump, where the heat is extracted. The cooled water is then returned to the ground via the absorption well
This closed water supply ensures sustainable use of the resource and prevents the groundwater level from falling. The exact design of the well system depends on local conditions and water regulations.
How much does a groundwater heat pump cost?
A groundwater heat pump costs between 12,000 and 18,000 euros, depending on performance and model. Additional falls 5,000 and 12,000 euros for the installation of the well system. In addition, there are the installation costs of the heat pump itself, which are approximately 2,000 to 3,000 euros amount to. Overall, the costs for a groundwater heat pump amount to 18,000 to 33,000 euros.
Here is an overview of the cost items:
The actual costs depend on the depth of the groundwater table, soil conditions and regulatory requirements for well drilling. Funding programs can reduce investment costs.
Are groundwater heat pumps being promoted?
Groundwater heat pumps are financially supported by the Federal Funding for Efficient Buildings (BEG). Both subsidies and low-interest loans are available.
- When replacing an old heater, the KfW subsidy, 458 be used. It covers up to 70% of eligible costs, but at most 21,000 euros for a single-family home.
- In addition, there is the KfW loan 358/359, which with an interest rate starting from 0.01% is granted. This can be used in addition to subsidies and allows loans of up to 120,000 euros per residential unit. Especially households with an annual income of up to 90,000 euros benefit from particularly favourable conditions.
Is a groundwater heat pump worthwhile?
A groundwater heat pump is worthwhile because it works particularly efficiently due to the consistently high temperature of the groundwater. As a result, operating costs are very low. Especially when replacing an old heating system, the investment can quickly pay off, as government subsidies of up to 70% of costs cover. This significantly reduces purchase costs and makes the groundwater heat pump an attractive alternative to fossil heating systems.
A calculation example shows that a groundwater heat pump is cheaper than a gas heating system in the long term. Thanks to lower operating costs and government funding, over 20 years of savings of almost 28,000 euros are achieved.
What is the experience with groundwater heat pumps?
Experience reports show that groundwater heat pumps are an efficient and sustainable heating solution when they are professionally planned and installed. Users praise in particular the high efficiency And the low operating costs.
However, there are also challenges. Some Homeowners report of Water quality issues, in particular due to high levels of iron or manganese, which can lead to deposits in the plant. Complex filtering or water treatment may be required here.
In addition, they hang Overall costs depend heavily on local conditions. During some users Expect quick payback due to low heating costs, others report high investment costs due to complex well drilling. In addition, a water permit is required, which can further delay the installation.
Do you need a permit for a groundwater heat pump?
For the installation of a groundwater heat pump, a Approval from the competent water authority required. Since water-water heat pumps use groundwater as a heat source, they must comply with the requirements of the Water Resources Act (WHG) and the respective state ordinance. Especially in water protection areas Are there strict requirements or even a ban. The permit usually includes an examination of the water quality, the flow rate and the return of the water via the absorption well.
How long does a water-to-water heat pump last?
A water-to-water heat pump has an average Lifespan of 20 to 25 years. However, the well system can be used significantly longer, often up to 50 years. Decisive for durability are the water quality, regular maintenance and protection against deposits such as iron or manganese residues, which can clog the heat exchangers.
What do I have to pay attention to with a water-to-water heat pump?
When operating a water-to-water heat pump, the following points are particularly important:
- Check water quality: High levels of iron or manganese can cause deposits and reduce efficiency. A water analysis before installation is essential.
- Get approval: The water authority must agree to the use of groundwater. Approval can be difficult in water protection areas.
- Suitable well system: Conveyor and absorption wells must be properly designed to ensure a sufficient volume of water and recirculation.
- Regular maintenance: Heat exchangers and filters should be checked annually to avoid efficiency losses and extend the life of the system.
- Note the sizing: For high efficiency, the output of the heat pump must be tailored to the heating requirements of the building.
What are the advantages and disadvantages of groundwater heat pumps?
Groundwater heat pumps are particularly efficient and operate independently of the outside temperature. They offer low operating costs and high environmental friendliness, but require approval and appropriate water quality. In addition, the investment costs are higher due to the required well drilling.
Is a groundwater heat pump the right choice?
A groundwater heat pump is ideal for well-insulated buildings with low heating requirements, when a sufficient amount of water is available and the water quality is right. It is particularly worthwhile when approval is granted and the higher investment costs are offset by low operating costs. Anyone looking for an efficient, environmentally friendly heating solution and meeting the requirements will benefit from this technology in the long term.
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