A geothermal manifold chamber is the central connecting element between the geothermal ground loops in the ground and the heat pump in the building. It houses the geothermal manifold, which collects the brine fluid from the various ground loop circuits and directs it to the heat pump. By installing it outside the building, you avoid core drilling through the building envelope, save valuable basement space and allow easier access for hydraulic balancing and maintenance work. GNV manifold chambers made of PE plastic guarantee maximum tightness and a service life of over 50 years.

GNV offers various geothermal manifold chamber models for different requirements: The compact models GN Box Mini, GN R Mini and GN R Compact are ideal for detached houses with 2-6 ground loop circuits. GN R Medium and GN 1 with up to 16 connections are designed for medium-sized projects. For larger construction projects, the GN 2 and GN 3 with up to 100 ground loop circuits are used. With load capacities of up to 40 tons (class D400) and a variable installation depth of 1.69-2.09 m, our premium products GN X1 and GN X2 offer maximum flexibility for demanding geothermal projects of all sizes.

PE manholes from GNV offer numerous advantages over conventional concrete manholes: they are completely watertight thanks to seamless welded joints in accordance with the standard, significantly lighter and easier to install, corrosion-resistant and insensitive to aggressive soil conditions. The shorter installation time saves considerable labor costs. In addition, our geothermal manifolds are equipped with pre-assembled connections, which minimizes the risk of installation errors. The longevity of over 50 years and the recyclability of the PE material make our manifold chambers a more environmentally friendly alternative to concrete. With the same load class (up to D400), GNV manholes are also often more cost-effective than comparable concrete solutions.

A high-quality geothermal manifold chamber such as the one from GNV significantly increases the efficiency of your heat pump system. The precisely welded connections and optimized manifold geometry minimize pressure losses in the system, which reduces the power consumption of the circulation pump and improves the seasonal performance factor (SPF) of the heat pump. Integrated balancing valves enable perfect hydraulic balancing of the individual geothermal ground loops, resulting in uniform heat extraction from the ground. This increases the efficiency of the entire geothermal system by up to 15% compared to non-optimized systems and noticeably reduces your heating costs over the entire service life of the system.

Depending on the model and size, the purchase costs for a GNV geothermal manifold chamber vary from around 800 € for compact solutions (GN R Mini) to around 5,000 € for large manifold chambers with many connections (GN X2). Although the investment initially seems higher than for simple solutions, it quickly pays for itself: you save on expensive core drilling, reduce installation time by up to 60% and avoid potential moisture damage in the building. The improved system efficiency also reduces the annual operating costs of your ground source heat pump by 10-15%. For an average single-family home, this means annual savings of 200-300 euros compared to a less efficient solution. Over the lifetime of 50+ years, these savings add up considerably.

The installation of a GNV geothermal manifold chamber typically takes place in just a few steps: First, an excavation pit is dug, the size of which should be about 50 cm more than the dimensions of the manifold chamber. The prefabricated manifold chamber is then installed using a crane or excavator and placed on a compacted gravel bed (15-20 cm). After connecting the geothermal ground loops and the supply line to the heat pump, a pressure test is carried out. The manifold chamber is then backfilled with gravel and compacted. No concrete casing is required for models with buoyancy protection. The telescopic cover enables precise adjustment to the final ground level. The entire installation takes only 2-4 hours, depending on the size of the manifold chamber, which significantly reduces construction time and labor costs.

For a typical detached house with a living area of around 150 m² and a heating load of 6-10 kW, geothermal manifolds with 2-4 ground loop circuits are ideal. We recommend our GN R Compact (up to 6 probe circuits) or GN 1 (up to 16 probe circuits) models for this purpose. The exact dimensioning depends on several factors: the number and depth of the geothermal ground loops, the output of the heat pump and the geological conditions of your property. If used as a heating and cooling system, you should choose a larger chamber type to allow for future expansions. Our experts will be happy to advise you on the optimum dimensioning for your individual geothermal project.

GNV geothermal manifolds made of high-quality PE material are designed for an exceptional service life of more than 50 years. They are corrosion-resistant, frost and UV-resistant and resistant to soil chemical influences. Thanks to the special welding process in accordance with the standard, we achieve absolute impermeability, which further increases durability. Maintenance is limited to an annual visual inspection of the manifold fittings and an occasional leak test. In contrast to concrete chambers, you do not have to worry about cracks or leaks. If necessary, balancing valves can be retrofitted to optimize hydronic balancing. These minimal maintenance requirements make our geothermal manifolds a particularly cost-effective investment for your geothermal system.

Yes, GNV geothermal manifolds are ideal for retrofitting into existing heating systems when renovating or converting to geothermal energy. The modular design of our manifold chambers enables flexible adaptation to existing pipes and systems. When converting from conventional heating systems to a geothermal heat pump, the geothermal manifold simplifies the installation considerably, as no new ducts need to be created in the existing building. Our manifold chambers also offer optimum solutions when extending existing geothermal systems with additional ground loop circuits. Our experts will be happy to advise you on the best integration into your existing system and create a tailor-made plan for your conversion to renewable energy.

Geothermal systems with GNV manifold chambers work reliably even in the depths of winter, as they utilize the constant ground temperature of around 10°C at great depths. Unlike air heat pumps, geothermal systems do not lose efficiency at low outside temperatures. Our geothermal manifolds are designed to be frost-proof and are protected from frost by the installation depth of at least 1.5 m. The special PE construction is frost-resistant down to -40°C. For very cold regions, we recommend our deeper models such as GN X1 and GN X2 with an extended installation depth of up to 2.09 m. The insulation integrated in the manifold chamber provides additional protection against heat loss. These special properties make our manifold chambers suitable even for alpine regions and extreme climate zones with very low winter temperatures.

Absolutely, GNV geothermal manifolds are ideal for so-called passive or active cooling in summer. With passive cooling, the natural ground cooling of approx. 10°C is used directly by passing the cooler brine through the heating system - this enables an energy-efficient reduction of the room temperature by 3-4°C without additional power consumption by the heat pump. For active cooling, the heat pump is operated in reverse mode, which enables a stronger cooling capacity. In both cases, the geothermal manifold acts as a central distribution station for the cooling liquid. Our larger models such as the GN 2 or GN X series offer sufficient space for additional changeover valves and control technology required for a combined heating/cooling system. This dual use makes your geothermal system with GNV manifold chambers an efficient air conditioning system all year round.

As a rule, no separate permit is required for the installation of a geothermal well itself. The permit requirement mainly relates to the geothermal ground loops or collectors. Depending on the federal state and local regulations, you must obtain a permit under water law from the relevant water authority for boreholes over 100 m deep. For shallower boreholes, a notification is often sufficient. Some local authorities have special requirements for geothermal systems in water protection areas. GNV geothermal chambers meet all the requirements of the water authorities with regard to impermeability and environmental compatibility. We recommend that you coordinate the installation of the entire geothermal system, including the manifold chamber, with your local building authority and water authority at an early stage. Our technical support can assist you with any questions regarding official requirements.