Basics of the geothermal heating

Heating, cooling and producing of domestic hot water

The Lämpöässä geothermal energy system is an entity which can heat and cool properties and also produce domestic hot water. The system is especially suitable for detached houses, terraced houses and blocks of flats. The geothermal energy system consists of heat collection circuit, ground source heat pump unit, heat distribution circuits, producing of domestic hot water. Cooling unit and solar collector can be added to the system also later.

Heat collection

A geothermal heat system consists of a network of heat collection pipes, a geothermal fluid mixture circulating within the network and a geothermal heat pump unit. Of the total energy required for heating, Lämpöässä collects an average of 75% from natural sources. The heating energy is collected via circulating water-ethanol or water-glycol mixture in the collector installed in the ground, a water system or a bore hole. Your Lämpöässä dealer will help you to design your geothermal heating system and a suitable heat collecting method.

Heat collection from the soil

The horizontal heat collection piping is installed 1-1.2 meters deep in the ground. During the installation process, take into consideration the possible earth fill on the lot. We do not recommend building a road for motorized vehicles on top of the collection pipes, and pipes running under a lightly trafficked driveway are to be covered with styrofoam for protection. Pipe trenches are to be dug with a steam shovel or a drainage trencher. Distance between trenchers should be 1.5 m. For leveling the bottom of the trench, machine work performed by a professional steam shovel operator is adequate.

Heat collection from the water system
Installation depth to the water is to minimum from 2 to 3 meters. Weights of 4 kg must be placed on the pipe every 2 meters to prevent the pipe moving. Due to the stream of the water, river installation is not recommended.

Heat collection from the energy bore hole
Normal depth of a single energy bore hole from 120 to 200 meters and diameter from 130 to 160 mm. There can be several energy bore holes depending on the energy demand. The energy bore holes can be realized with two or three pipe (two down, one up) systems. In bore hole solutions the pipe must be insulated from the bore hole until the foundation of the building.

Heat distribution

The most common method of heat distribution in Finland is underfloor heating. However, in other countries such as the UK, radiators are still very popular. Both solutions are suitable with the Lämpöässä heat pump. There can be 1-3 heat distribution circuits. There is a possibility to use up to three heat distribution circuits with Lämpöässä heat pump.

Underfloor heating requires a flow temperature of 28-40°C and radiators a flow temperature of 30-55°C. Underfloor heating is more effective in terms of COP (coefficient of performance) but even old radiator networks can be used thanks to superheat technology and high standard compressors.


A cooling system installed into the Lämpöässä heat collection circuit is an affordable cooling solution, as the only fixed costs consist of electricity costs for operating the water circulation pump and cooling fan, raising the operation efficiency ratio as high as 40. With the ÄssäCooling system, the room temperature can be kept at a pleasant level throughout the year. The fluid in the circuit is circulated through the heat exchanger, which releases cooling energy into the indoor air. The costs of the ÄssäCooling system are a fraction of the costs of for instance an air source heat pump.

Solar collector

Nearly all Lämpöässä heat pumps can be connected to a solar heating system. However, at the moment only the Vm series pumps are fitted with pre-installed additional heating connections for the solar heating system. Connecting the heat pump to a solar heating system results in almost free hot water and heating during the summer. The large integrated water storage tank’s performance is enhanced with the solar energy. The solar heating system can also be connected to the heat pump separately afterwards.