Stoltinmaja will soon have a solar-powered sauna

The board of As Oy Stoltinmaja, located in Runosmäki, Turku, decided to put energy issues right once and for all. The biggest expenditure item is the switch from district heating to geothermal heat, which will cut the amount of purchased energy by around 71%.

“All options were considered, and geothermal was the clear winner. The best thing is that there is no need to increase the maintenance charges for the renovation, but the project is paid for with the savings from geothermal heating. After nine years of payments, we will probably be able to lower the contributions,” says Kari Hirvonen, chairman of the board of Stoltinmaja.

The company consists of six blocks of flats and 111 apartments. The investment decision was facilitated by an ARA energy grant of around EUR 400 000. The energy renovation will be carried out by LeaseGreen and the results will be the responsibility of LeaseGreen.

For geothermal energy, an estimated 15 energy wells with a total depth of 5 000 metres will be drilled on the site. In addition to geothermal heating, exhaust air heat recovery will be installed and the building automation system will be upgraded. In addition, an exceptionally large solar power plant of 115 kilowatts will be installed on the roofs of the houses. The roofs of six apartment buildings are almost entirely covered by solar panels.

“It supplies electricity for the building’s saunas, cold rooms, stairwell lights and yard lights. Solar power can also be fed into the apartments and sold to the national grid,” says Hirvonen.

Another special feature is that temperature and humidity sensors are installed in each apartment. In general, there are only a few dwellings with condition sensors. Comprehensive metering reduces unnecessary maintenance visits and helps improve energy efficiency by allowing precise control of heating water flows to the apartments.

In addition to cost savings, the board is motivated by responsibility and green values. The project will reduce the carbon footprint of the housing company by around 70%.

“We will become fossil-free and green. So let’s be fashionable!” Hirvonen gloated.

LeaseGreen specialises in serving large housing companies. According to Thomas Luther, CEO, Stoltinmaja is a good example of a housing company that is ahead of its time.

“Cost savings are the number one motive, along with energy independence and ecology. We guarantee results so that the purchase is safe and there are no surprises.”

As part of the cooperation, LeaseGreen will guarantee that the SCOP of geothermal heat will remain at least at 3.4. The benefit guarantee is part of the LG Meta service contract, which is initially signed for five years. The contract includes remote monitoring to proactively optimise energy consumption and conditions according to weather conditions. For this purpose, digital twins of geothermal and LTO systems and condition measurements will be modelled. Monitoring improves energy efficiency and reveals faults quickly.

The Stoltinmaaja board of directors put several service providers out to tender and was impressed by LeaseGreen’s expertise and technology.

“The spirit of doing LeaseGreen gave me the confidence that now we are really getting what we ordered. I got the feeling that we had found an operator that stands behind its business honestly,” says Hirvonen.

The energy renovation in Runosmäki will start in November and will be completed during next spring.

Further information

Kari Hirvonen, Chairman of the Board, As Oy Stoltinmaja
+358 500 726 790, karihirvonen@hotmail.com