Case Study: Prästgårdens Förskola (Prästgården Pre-School)

Short Description

The greatest difference in relation to an ordinary pre-school building construction is that Eksta, together with those who are to run the operation, jointly and at an early stage in the building process applied an overall approach in order to halve energy consumption at the pre-school. The project ‘Prästgården Pre-school’ had the objective of first reducing energy consumption by 50% to less than 50 kWh/m2 per year for heating, hot water and all electricity, and second to erect a building that functions well in relation to the operation. The Project was implemented as a partnership project. The users of the pre-school, that is to say the staff, were also involved from day one, when the first proposals regarding the structure were received. The staff were involved in the building meetings and could influence their future workplace. Participation in the project has resulted in the staff becoming aware, well-informed and engaged. The Pre-school was built with passive house technology, and supplementary heating comes from the Eksta heating system – production is provided by solar panels and biofuel. Prästgårdsängens Pre-school is consequently Sweden’s most energy efficient pre-school.

Key Elements

Certification

Prästgården Pre-school has been built with passive house technology, but is not certified as such. This is because certification would mean that Eksta must manage regular reporting, which they do not do. But the Pre-school satisfies the standards that are set for a passive house. As Eksta chose to build using passive house technology the square metre cost, 946 kr/m², was greater than it would cost with not building in an energy efficient way. In order to reduce energy further, an endeavour has been made with the situation of the building to have it placed where the wind load is less.

Capacity Building

The craftsmen had previous experience of a passive house and of working in a partnership project. In addition to this, Eksta chose to go through, both with the Pre-school’s staff and the craftsmen, what a passive house is and what this means. The housing company wanted all those involved to understand that a building without a heating system was not anything strange and to enhance energy awareness.

Funding

Eksta received 70% of the investment costs for the solar cell plant, about one million, as a grant. No further grants were received for the project. As of Eksta choosing to build using passive house technology, the investment cost was 6½% higher, but the energy use also reduces by 50% to about 50 kr/m² per year. The housing company estimates that the higher investment cost will be repaid in eight years at current energy prices. 

Thermal Insulation

Eksta has used traditional insulation, which is a mixture of EPS and mineral fibre. Walls and roofs have a total of 400 to 500 mm insulation and under the cement slab the insulation is 300 mm EPS.

Windows and Shading

The U value of the windows is 0.8, which is the best available on the European market.

Ventilation

Ventilation is 0.3 l/s per m². The ventilation has heat recovery, known as an ‘FTX system’, that provides balanced ventilation that allows the same amount of air in and out.

Heating and Hot Water

The Pre-school’s hot water comes from biofuel and solar energy

Solar Photovoltaic

The solar cell plant is 240 m² in size and produces 20 000 kWh per year.

Electricity Saving Products

The Pre-school has energy efficient illumination such as presence-controlled outdoor illumination, natural light sensors and light-emitting diodes both outside and inside. Drying cabinets, which are important for a pre-school in Sweden, have moisture control installed, which means that the cabinet turns off when the clothes are dry instead of running for hours. This measure is very effective in saving energy.

Main Results

It is still too early to say what the most important results of the project are, as the Pre-school was only completed almost a year ago.

Lessons learned

Eksta has not seen any great weaknesses with the project so far. It is satisfied with the project from the prospective of use and operation. However, they are not completely satisfied with the design issue, as for instance, they wish to reduce the sound from the ventilation.

The strongest point with the project is that Eksta was in reality able to demonstrate what the costs are for building energy efficiently and that these are negligible. With Prästgården Pre-school they have shown that it is fully possible to not only build homes using passive house technology, but also non-residential premises. They have also demonstrated that building energy efficiently does not differ so much from more traditional projects and that it is therefore of great importance that energy efficiency measures are applied.

Additional Information

Eksta Bostads AB has exclusively invested in renewable energy sources and has solar cells, solar heating, geothermal heating and pellets. The housing company has also built passive houses. They have consequently had many study visits, and they also believe that they have inspired others. Eksta hopes that with their focus on energy efficiency they will be able to get others to understand its importance.