At the hospital in Sønderborg, gas is now history. Two cutting-edge heat pumps have taken over, reducing CO₂ emissions, improving indoor comfort, and supplying excess heat to the local district heating grid. It’s a straightforward solution with significant potential for replication worldwide.
91 %
15800
The future of green healthcare
Sønderborg Hospital is leading the way for a more sustainable healthcare by replacing outdated gas boilers with energy-efficient heat pumps.
This innovative system not only provides heating and cooling for the hospital but also utilizes excess heat — covering 91 % of the hospital’s heating demand — and even contributes to the local district heating network.
What’s more, the heat pumps enable comfort cooling at the hospital, making the indoor climate much more pleasant for both patients and staff.
By optimizing its energy flows, the hospital is significantly reducing its carbon footprint, offering a model that could inspire hospitals worldwide.
What drove the results?
Why heat pumps and hospitals are the perfect match
Ever noticed how the back of your refrigerator feels warm? Whenever cooling something, the extracted heat is released somewhere else – known as excess heat.
The new heat pumps at the hospital in Sønderborg work in the same way. When they cool down, they generate heat, which can now be captured and utilised.
This mechanism holds great potential in buildings that require both heating and cooling, such as hospitals. Hospitals use heating for patient rooms, offices, and domestic hot water, and cooling for medical scanners, technical equipment, and operating rooms.
By utilising both excess heat and cooling, the hospital optimises its energy efficiency across all processes.
Turning waste into community benefit
One of the project’s most notable aspects is its ability to capture and reuse excess heat. As the heat pumps cool critical hospital infrastructure, the extracted heat is redirected to warm the hospital’s own facilities. An impressive 91 % of the hospital’s total heat demand is now met by excess heat, with only minimal district heating needed during the coldest months.
Any excess heat that the hospital does not use itself is transferred to the local district heating network, where it helps warm private homes in Sønderborg. The system is expected to supply 15,800 MWh of excess heat to the heating network each year – enough to cover the heating needs of approximately 877 Danish households.
By acting as both a consumer and supplier of energy, Sønderborg Hospital showcases the potential of sector coupling, where energy flows between different sectors to optimize overall efficiency.
A green blueprint for hospitals worldwide
By utilizing excess heat internally – that used to be wasted into the air – and supplying excess heat to the local district heating network, Sønderborg Hospital now helps reduce the overall heat production in the Sønderborg area by 28,300 MWh every year.
In other words, this project is more than just an upgrade at the hospital – it’s a blueprint for how large institutions can actively contribute to a greener, more sustainable future.
Beyond its environmental impact, the new system also improves the indoor climate for both patients and staff. The heat pumps enhance air quality and temperature regulation, ensuring greater comfort in patient rooms, waiting areas, and workspaces.
By electrifying its heating system, reducing emissions, and supporting the local energy network, Sønderborg Hospital is setting a powerful example of how healthcare facilities can lead the way in decarbonization. The modern hydronic system is not only effective — it’s scalable, making it a viable solution for hospitals and large institutions around the world.