As Oy Honkakukkula is a housing company of row houses in Siivikkala, Ylöjärvi, built in 1977. The company covers a total of 20 apartments in 4 separate houses as well as a storage/heating station building.
Sami Kokkonen, chairman of the board for housing company Honkakukkula, explains that the homes are mainly two-bedroomed apartments and that the total heated space is 1,604 m2 in residential areas and 125 m2 in the service building.
”The renewal of the water supply system became topical for our housing company, and we decided to use the coming renovation to also switch to ground source heat. The choice of ground source heat came about after hearing positive experiences from other, similar housing companies. The bedrock under the plot is close to the surface, and all calculations pointed to the fact that a ground source heating system would be cost-effective. We decided to sort out both our water supply and heating in one go,” Sami Immonen explains the background for the renovation.
Carefully planned, successfully implemented
The decisive factor in the selection of supplier was the retailer’s ability to offer a ground source heating solution that matched the requirements of Honkakukkula.
”Pirkanmaan Automaatiokeskus Melo Oy was the only supplier in the area able to provide an offer and plan to suit our request of retaining the old oil vessel to serve as an additional heat source. The old oil vessel still had some years of service left. Therefore, it was more efficient in light of the total financial situation to maintain oil heating in addition to ground source heat in order to cover peaks in consumption,” Immonen explains.
The carefully planned ground source heat renovation began at Honkakukkula with a few days of heat well boring in the early autumn of 2015. The heat well field at Honkakukkula includes seven 275-metre deep wells. The ground source heating system consists of the Gebwell Gemini64 and T20 heat pumps and two 1,000-litre accumulators. The system also includes energy meters to provide accurate information on electricity consumption.
”The bedrock on the plot was so close to the surface that channels had to be excavated for the pipes, but this was taken into account already in the plans,” Immonen describes.
After the old, 20,000-litre overground oil vessel was dismantled from the heating station, there was enough room to fit the entire ground source heat equipment as well as the remaining 1,500-litre oil vessel used for additional heating.
According to Sami Immonen, the renovation caused no major disruptions to the residents. In practice, all Honkakukkula apartments were occupied during the project. Over the course of the winter season, the ground source heating system was installed parallel to oil heating in all four of the houses.
”As the project progressed, more houses were connected to ground source heat, and by spring the final apartments were included in the new heating system,” Immonen says.
Savings of 17,300 € thanks to ground source heat
At Honkakukkula, consumption readings are collected from the ground source heating system with a built-in electricity meter. According to Sami Immonen, the estimated energy calculations included in the retailer’s offer have been proved accurate by the real-time tracking of consumption. Immonen is very satisfied with the reduced heating costs of the housing company.
”Back in the days of oil heating, our yearly heating expenses were about 30,000 euros. Since the switch to ground source heat, the costs have totalled to 1,400 € in oil and about 11,300 € in electricity consumption. In other words, with ground source heat the total heating costs of the housing company are now about 12,700 €, adding up to yearly savings of 17,300 €,” Immonen calculates.
The ground source heat renovation incurred no insurmountable expenses for the residents of the housing company, as the project was partially funded with savings.
”We calculated that the investment, funded with a renovation loan for the housing company, will be paid back in full in 8 years for the ground source heat,” Immonen says.
Easy to use and installed without problems
”For us, the result was an easy-to-use ground source heating system that was delivered and installed without any problems. Everything went according to plan. I received training to operate the system, but have not needed to adjust any of the equipment myself. The remote monitoring works well, and I am able to observe the system’s operation from my living room couch. I also receive email notifications in the event of any problems,” Immonen describes the user-friendliness of the system.
With Gebwell’s pumps and accumulators, the system has operated without any issues. Residents of the housing company have been pleased with the result.
”We have had no lack of heating. Warm water has also been plentiful. We are able to monitor the true heating costs with our own meter that also displays the electricity consumption of the circulation pumps. The promised savings in costs have come true,” says Sami Immonen from As Oy Honkakukkula.
”Based on my experiences, I would recommend the Gebwell ground source heat project to, for example, older row house companies with high oil consumption. At our housing company, we have been very satisfied with the decrease in costs after switching to ground source heat,” Immonen states.