NERO - Nearly Zero Energy Wooden Buildings in Scandinavia

NERO promotes large-scale market uptake of the developed nearly Zero Energy Wood Buildings low-carbon solutions, applicable for construction industry design and procurement process.



NERO project develops and demonstrates technical solutions, which significantly reduce the overall costs of new nearly Zero-Energy Wooden Buildings (nZEB) and districts compared to the current situation.

The European energy policy push the member states to transform building stock into nZEBs. By the end of 2020 (2018) all new buildings owned by public authorities should comply with the Energy Performance of Buildings Directive (EPBD, 2010) obligations.

Many member states have already shifted minimum energy performance requirements to the cost optimal level. In Nero we are also presenting the report “nZEB energy performance requirements in Nordic vs. EC recommendations”. The direct comparison of the building energy performance between the EC recommendation and the countries nZEB primary energy values produced inconsistent results because of the variation of both the primary energy factors and the energy calculation input data in national regulations.

NERO project has in the first step collected data from eleven (11) existing during 2013 – 2017 built wooden public, indirect public or private owned buildings in Estonia, Finland, Norway and Sweden, in order to be able to assess possible differences between predicted and actual energy and indoor environmental performance, as well as differences in building structures and technical systems.

Focusing on five (5) day care centres Nero report D2.2. (location mentioned down here) showed that in general, the thermal environment and indoor air quality responded to the highest indoor climate categories I and II. Heating and ventilation systems in these and all buildings are working without major problems. Good indoor climate conditions also reflected in the day care centre personnel satisfactory questionnaires. For most of the studied buildings, over 80% of the people marked all indoor environment condition parameters (thermal comfort, indoor air quality, acoustics, odour and illuminance) acceptable.

Energy consumption analysis showed that problems exist between the calculated and measured values. In the most of these 5 studied buildings, measured energy consumption is higher or even significantly higher than designed values. Most potential causes of the higher actual energy consumption are differences of measured and designed solutions, methodology of the energy calculations and the differences in the user behaviour.

Lessons are from previously constructed nZEB buildings now learnt, and they will further be utilized in Nero in planning which kind of building properties could guarantee fulfilment of new or existing national nZEB requirements.

For an overview of the full reports, see the Research – section under work package (WP) 5 “nZEB energy performance requirements in Nordic vs. EC recommendations”. Research – section under work package (WP) 2 “D2.2 Energy and indoor air quality and comfort auditing report”



NERO develops and demonstrates technical solutions, which significantly reduce the costs of new nearly Zero Energy Wood Buildings and districts compared to the current situation. On site and nearby renewable energy system solutions are studied in order to provide real addition of renewable energy production and to provide solutions, which are optimal on local grid and energy system level.

NERO implements a life cycle analysis (LCA) in chosen cases in order to quantify the effect of embodied energy in energy balance.

Project partners:

  • Aalto University, Helsinki, Finland
  • Tallinn University of Technology, Nearly Zero Energy Research Group, Tallinn, Estonia
  • Sintef Building and Infrastructure, Architecture, Materials and Structures, Trondheim, Norway
  • Växjö Kommunföretag AB, Växjö, Sweden
  • Kouvola Innovation Oy, Development Team Biovalley, Kouvola, Finland


Project duration from 1.9.2017 to 30.8.2020


  • "NERO focuses to nearly zero energy buildings (nZEB) in a cold climate with a good coverage in Nordic countries. In such a severe climate, heating is clearly dominating and the cost of heavily insulated nearly zero energy buildings is evidently challenge. There are two other issues that are common in Nordic countries. In all of these, developed energy calculation methodologies relying on dynamic simulation offer a large degree of freedom in design, promoting the development of cost effective solutions. Wood is another common thing in Nordic countries, as there are massive resources and good skills to manufacture and construct wooden buildings. Wooden buildings may have an edge to keep the wall thickness under control in highly insulated nZEBs as capable to combine loadbearing frame and insulation within the same wall layer. Prefabricated wooden buildings could provide solid option to achieve nZEB requirements in a cost effective manner – that’s the main objective of NERO project to be demonstrated with best practice case studies." Jarek Kurnitski, professor of Nearly Zero Energy Buildings, Aalto University, Finland


  • "Since both energy efficient buildings and buildings with wooden construction are of great importance in Växjö Municipality we look forward to this NERO project for important knowledge contribution!  We have been working within these areas for many years and have received a lot of attention. The NERO project will be one of the measures that helps us to reach our target with zero fossil carbon dioxide emissions by 2030, help us to continue developing and to keep the position as a front runner.” Johan Thorsell, verksamhetsutvecklare trä/byggnation, Kommunledningsförvaltningen & VKAB, Växjö, Sverige

  • “Kouvola has already anticipated the requirements of the new FInZEB legislation. All of the new wooden frame public service buildings being built in this decade largely follow this new legislation to come. With the NERO project this accumulated level of knowledge will strengthen, and as wooden construction projects will be enlarged and diversified this will open up to our advanced actors a wider market. It is great to have recognition given by the EU and opportunity to continue our work, together with our competent Nordic partners." Tero Hasu, coordinator, specialist, Circular Economy, Kouvola Innovation Oy, Kouvola, Finland

  • "Estonians have long historical traditions in producing wooden buildings. Today the manufacturing of wooden buildings has developed to one of the key industries in Estonia with 140 enterprises and around 85-90% of houses are exported. The Estonian wooden houses industry is the most successful exporter in Europe; and the seventh largest overall. The NERO project helps to step forward to more energy efficient and moisture safe wooden building with reduced cost." Targo Kalamees, professor of Building Physics, Tallinn University of Technology, Estonia

  • "SINTEF Building and Infrastructure has a long-lasting experience on wood constructions and instituted several streams of research covering architectural possibilities of wood-based building products, laboratory testing of thermal and hygrometric properties of wood products, and optimization and research in wood construction systems. A long-lasting collaboration with the Research Centre on Zero Emission Buildings and the Research Centre on Zero Emission Neighborhoods in Smart Cities strengthened the knowledge and expertise in nearly zero energy buildings where wood is the main construction material. The NERO project is therefore an excellent opportunity to contribute with past experience and acquire knew knowledge in wood constructions and nearly zero emissions buildings." Nicola Lolli, research scientist at SINTEF Building and Infrastructure, Norway



Kouvola Housing Fair 2019, video
Nero – project has studied Kouvola Housing Fair 2019 detached houses – their energy performance and a carbon footprint calculations for one typical 2-storey house, with different structural solutions. The local district heat (94% renewable, 6% natural gas) has a very low specific emission factor. Our presentation is available on the Nero-project website,, under ”Presentations”, under Nero workshop Helsinki Jätkäsaari 25.9.2019 - section, 3. presentation “Kouvola Housing Fair”.       



Photo: Lukas Pearsall

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