Helen built a renewable energy heating solution for the Sakarinmäki school complex in Östersundom, which was fully commissioned in August 2014.

Sakarinmäen koulussa toimii hybridilämmitysjärjestelmä

The hybrid heating system consists of geothermal heat, solar heat, a heating plant and heat storage together. Building of the heating solution for the Sakarinmäki school complex is Helen’s pilot project for testing new kinds of energy solutions, and it is also the first step in a more extensive trial taking place in Östersundom.


In June 2014, 16 solar heat collectors with a combined area of 160 square meters were installed at the Sakarinmäki school. Two chargers of 4,000 litres were also installed for storing solar heat.

Solar heat complements the hybrid solution used for heating the school. The 21 bore holes of the geothermal heat system were made already last year.

- Geothermal heat was introduced in early January 2014, and it has been producing heat ever since. It was easy to integrate solar heat with the hybrid heating system, says Project Manager Jaakko Tiittanen.

- In the summer, there was even too much heat, and consumption and the sun did not match up. During the autumn, we made some minor tweaks to the system to finish off the final adjustments, he continues.

In the winter, geothermal heat and solar heat are complemented by the heating plant using light fuel oil. In March last year, bio oil was introduced as fuel at the heating plant of the school. During the spring and autumn, we tested the functioning and impacts of a blend of bio oil and fuel oil.

The entire system was taken fully into use in August 2014 at the start of the autumn term. The original target of producing 80 per cent of the school’s heating with renewables was reached, and even exceeded after August. Since August, about 80 per cent of the heat used by the school has been produced with geothermal pumps and solar collectors, and the rest mainly with bio oil in the heating plant.


In autumn 2014, we installed computer displays for students and teachers at the Sakarinmäki school for monitoring in real time how much energy is obtained from geothermal heat, solar collectors and the heating plant and what it means, for example, when converted into warm showers. This information can also be seen on Helen’s website.

Helen has involved the pupils and teachers of the Sakarinmäki school from the start to think up ideas on making energy a visible part of the everyday life and teaching at the school. We have organised several workshops for teachers and pupils to brainstorm how to include energy issues in the lessons.

The pupils and the school staff have been enthusiastic to learn about the new heating system. Issues related to energy production become familiar when the production and consumption data of their own school is examined during the lessons of various subjects.