Energy retrofitting an existing building and adding two new buildings around a large communal garden with the ambition of reducing the emissions by 50% was the challenge faced in the project Ulsholtsveien 31, or U-31 – the housing for youth. The project is the first residential development built within the Norwegian Program FutureBuilt (2010-2020), which co-finances 50 pilot buildings with the lowest possible greenhouse emissions. The project, that started in 2013 and finished in 2017, is committed to climate friendly architecture and provides a way to make tenants aware of their energy consumption.
In the plot of 4,8 ha the new houses were placed in the west side upright to the existing building. This disposition enabled the creation of a large common area which is used for gardening and as a space for social encounter.
Departing from the premise that “form follows climate”, the architects rehabilitated and adjusted the existing building for residential purposes and build up two new buildings. The two new buildings in the plot are passive houses built with cross-laminated timber and home for 27 families/individuals. Offering a diverse program with flats varying from 32 to 64 m2 of floor area the complex is attractive to diverse social groups. Furthermore, the tenure model which allows residents to occupy the flats for the maximum of period of six years, aims at giving opportunity to new residents to move in, enjoying living in affordable housing without compromising the quality of life.
Heeding the goal of decreasing energy and resource use by 50%, the project adopted several technologies. The heat pump, consisting of eight pieces 190m depth energy wells (geothermal) is the main source of energy. All south faced roofs harvest solar energy and the system is connected to the internet for registration and monitoring of energy production while notifying residents of their consumption. Furthermore, greywater heat is recovered with heat exchanger in the waste pipeline which removes the heat continuously from the waste water. The energy obtained with this process preheats the incoming cold supply water. In the parking area, two double charging stations for electric / hybrid cars are set up with 3.7kW and 11kW charging power respectively.
Collaboration between planners, suppliers and contractors was fundamental to achieve the efficient and climate-friendly housing for young people just starting out. The project was a platform for material research. For example, humidity is monitored from hogged trees in the forest and until several years after being used in a building and the acoustical capacity of materials was investigated by multi-disciplinary team.
The solar power (PV) plant implemented in the south faced roofs of the buildings is expected to produce 23,000 KWh per year. The interface with grid companies enables the energy surplus to be used by neighbours. The project received the Architectural award 2017, which is a prize given by the three Norwegian associations: The Architectural Association (NAL); the Interior Architects Association and Furniture Designers Association (NIL) and the Landscape Architects Association (NLA).
With a limited budget the U-31 project has shown that is possible to make environmental friendly and affordable houses for youths. The project is a flagship for future housing projects in Norway and has received a large number of visitors including students, academic institutions and professionals from all over Europe.