Association Ljuskärrsberget

Lagest ground source heating project ever!

The background

Ljuskärrsberget is one of the largest ever ground source heating projects to be conducted in Sweden and Europe. The 500 apartments covered by the project belong to the Ljuskärrsberget tenant-owners’ housing association in Saltsjöbaden outside of Stockholm. It is estimated that the new system will save the association an annual total of 3.5 million kWh. That is equivalent to 350 tonnes of CO2.

The association is very large, comprising some 500 apartments divided into 13 groups of buildings. All in all, that means 52 buildings to manage and maintain! What really makes this project unusual is that the contracting company, Enstar AB, is installing more than just heat pumps. It is also converting all the apartments from direct electric heating to a distributed water heating system.

Chair of Ljuskärrsberget Association, Mathias Skoglund, explains, “In the past five years, our energy costs have increased by 100% to about SEK 10 million a year”.

“We were forced to take action. We were quite powerless to change the situation in any way. But now we’ll have a system that not only saves money and benefits the environment, it will also increase the value of all our members’ apartments.”


This project is enormous in all respects. It’s no easy job installing distributed water heating systems in 52 buildings and 500 apartments. Not to mention the work of installing a ground source heating system. It involves drilling no less than 156 boreholes to a depth of approximately 230 metres each. The heat from the boreholes is piped to 13 boiler rooms, each equipped with two NIBE F1330 ground source heat pumps and two VPB750 water heaters. That’s a total of 26 water heaters and 26 ground source heat pumps each with a capacity of between 40 and 60 kW.


Once everything has been completed, it is estimated that some 3.5 million kWh can be extracted annually from the bedrock - for free. The project is expected to deliver an annual cost saving of almost SEK 5 million. The saving will be even greater if the cost of electricity continues to rise.