Project information

Index: 0499R2
Priority:1: Innovation and the knowledge economy
Sub Theme:Innovation, research and technology development
Location SUOMI / FINLAND MANNER-SUOMI Lahti Etelä-Suomi Start/End date of the practice
Start: 2008
End: ongoing

Topic of the practice

Energy efficient urban housing

Good Practice Information

The MERA-building concept “low energy consumption in construction” is a new and very promising innovation to cut energy consumption also in blocks of flats. The concept was developed by RKL Reponen as the leading partner with VTT (Technical Research Centre of Finland) and several Finnish companies of the building sector.
The objective of the measure is to reduce housing costs by reducing the overall consumption of energy by 50%. Heating costs of buildings in Finland form 22% of the total energy consumption, which, regarding also the industrial structure (a lot of energy consuming forest industry) is a high figure.
Weather conditions and temperatures in Finland vary a lot. During one year the variation can be as much as 60°C. Therefore, energy efficient housing is very important. While numerous innovations deal with energy efficiency in single family detached houses, energy efficiency solutions in multi-story buildings have been rather rare.
MERA-block of flats use passive heating and are optimised to save energy. They do not have radiators of the central heating system, they utilise the heat from people, solar energy through the windows and the heat from household appliances. If additional heat is needed, it is taken from air ventilation.
The walls, roof, floor, windows and doors of the building are built carefully and with new techniques; the waste of heat is minimised and the airtightness of the structures is assured. Wasting of heat is reduced down to half or less of the initial consumption. A proper ventilation system is of crucial importance and the most important component in MERA-block of flats. The heat energy of the exhaust air is collected and reused. The electric appliances are chosen to use less electricity.
Taking contextual differences into consideration, the possibilities to transfer the good practice seem to be promising, both as a methodology and as a commercial product. Possible challenges are mainly related to managing the business processes and the value network during the construction phase.

Evidence of success

Cutting down of the energy consumption of blocks of flats by 70% compared to the normal reference building with increased construction costs of only 1.7% higher than the costs of a normal house built according to the building regulations.
After implementing the first MERA block of flats in the rural town of Heinola RKL Reponen Oy has built more MERA block of flats in Helsinki, in the Capital of Finland. Päijät-Häme / Lahti Region with five other regions are developing further applications of MERA block of flats in the Southwood project partly financed by ERDF.

Contact details to obtain further information on the practice

Vesa Ijäs

Lahti Science and Business Park

Annex completed on: 03-23-2011

As of 31 December 2015, this website is no longer updated. Follow news on interregional cooperation at