Strandslottet – this is a large holiday apartment complex by the sea in Bornholm. Previously, this historic building was heated only with direct electric heating panels.
Situation
The total annual electricity consumption for heating was approximately 206,925 kWhWith an average electricity price on Bornholm in 2025 of around 3.10 DKK/kWh (including taxes and fees), this resulted in an annual heating cost of approximately 640,000 DKK in annual heating expenses.
High energy consumption and the desire to find a more durable, future-proof solution prompted the client to undertake a comprehensive modernization of the building's heating system.
Solution
Step 1: New hydraulic heating system
Since the building was previously heated only with electric panels, it did not have a water-based heating system. During the project, a completely new hydraulic heating system was installed throughout the building.
Approximately 100 radiators have been installed, selected according to the building's heating needs. This created conditions for implementing a centralized heat pump system, characterized by significantly higher energy efficiency.
Step 2: IGLU air-to-water heat pumps
The building is now heated to 6 IGLU INUIT MONO heat pumps, each with 16 kW of power.
The system is configured in a cascade principle - several units work together and adapt to the overall heating needs of the building. This solution ensures both high power and flexible operation.
Main advantages of the cascade system:
• high overall heating capacity for larger buildings;
• gradual power adjustment according to actual demand;
• high reliability – even if one unit stops, the system continues to supply heat;
• higher efficiency under partial load.
The installation work was carried out by Vejleby VVS, while X-Energy and IGLU TECH supplied the heat pumps and provided technical support for designing and configuring the system.
Results
1) Energy Savings
Direct electric heating operates at 1:1 efficiency – 1 kWh of electricity produces 1 kWh of heat. The heat pumps installed at Strandslottet produce an average of about 3 kWh of heat from 1 kWh of electricity (COP ≈ 3). This allows for an expected energy savings of approximately 60–65% compared to the previous system.
2) Greater comfort
The project also significantly improved comfort throughout the building. In several common areas, the temperature has been increased, and the heat is now distributed more evenly. This ensures a more stable microclimate both in the apartments and in the common areas of the building.
3) Future-proof solution
The heating modernization is part of a broader building renovation plan. The Strandslottet board has prepared a 10-year maintenance and improvement plan, with key priorities being energy optimization and the modernization of engineering systems.
Additional advantage
Bornholm is an island, so transportation and service visits here cost more and take longer than on the mainland. For this reason, reliability was one of the most important criteria in the decision-making process.
The cascade system ensures redundancy – even if one device temporarily stops, others continue to supply heat.
Remote monitoring and diagnostics via the IGLU Platform provide continuous system oversight. Operational data can be analysed online, and minor adjustments can be made remotely, reducing the need for on-site service visits and providing peace of mind for both installers and occupants. Discover all IGLU heat pump solutions here.
