Although buildings produce a third of greenhouse gas emissions, it has been suggested that they might be one of the most cost-effective climate change mitigation solutions. Among building materials, wood not only produces fewer emissions according to life-cycle assessment but can also store carbon. This study aims to estimate the carbon storage potential of new European buildings between 2020 and 2040. While studies on this issue exist, they mainly present rough estimations or are based on a small number of case studies. To ensure a reliable estimation, 50 different case buildings were selected and reviewed. The carbon storage per m² of each case building was calculated and three types of wooden buildings were identified based on their carbon storage capacity. Finally, four European construction scenarios were generated based on the percentage of buildings constructed from wood and the type of wooden buildings. The annual captured CO₂ varied between 1 and 55 Mt, which is equivalent to between 1% and 47% of CO₂ emissions from the cement industry in Europe. This study finds that the carbon storage capacity of buildings is not significantly influenced by the type of building, the type of wood or the size of the building but rather by the number and the volume of wooden elements used in the structural and non-structural components of the building. It is recommended that policymakers aiming for carbon-neutral construction focus on the number of wooden elements in buildings rather than more general indicators, such as the amount of wood construction, or even detailed indirect indicators, such as building type, wood type or building size. A practical scenario is proposed for use by European decision-makers, and the role of wood in green building certification is discussed.

Depletion of natural resources and climate change are undoubtedly the biggest challenges that humankind faces today. Here, buildings have a crucial role since they consume the majority, i.e., 30% to 40% of the total energy resources. Green building certification is one of the solutions to limit the energy use in buildings. In addition, it is seen to indicate a consideration for sustainability aspects in construction. LEED is the most widely used certificate worldwide. However, recently some critics have raised doubts about LEED and whether it actually implies sustainability. Most of the criticism has been targeted to the energy aspects of LEED. Nevertheless, there is no consensus on the usefulness of LEED: is it really beneficial for the environment, and is it worth of the money and time invested on the certification process? In this study a critical analysis of the literature to find an answer to this question is presented. Altogether 44 peer reviewed articles dealing with the abovementioned issue were selected out of 164 search result. Based on the studied material, the different aspects of LEED from the viewpoint of energy-efficiency are discussed. From the 44 reviewed articles, ten articles state that LEED certificate indicates energy efficiency while eight papers end up with an opposite conclusion. The rest of the papers do not take any stand on this matter. The study showed that energy efficiency of LEED-certified buildings is questionable especially at lower levels, i.e., certified. Therefore, it is recommended to modify the Energy and Atmosphere category of LEED in order to improve the actual energy performance of buildings.

Around 40% of global energy consumption can be attributed to the construction sector. Consequently, the development of the construction industry towards more sustainable solutions and technologies plays a crucial role in the future of our planet. Various tools and methods have been developed to assess the energy consumption of buildings, one of which is life cycle energy analysis (LCEA). LCEA requires the energy consumption at each stage of the life cycle of a product to be assessed, enabling the comparison of the impact of construction materials on energy consumption. Findings from LCEAs of buildings suggest that timber framed constructions show promising results with respect to energy consumption and sustainability. In this study a critical analysis of 100 case studies from the literature of LCEAs conducted for residential buildings is presented. Based on the studied material, the embodied, operational, and demolition energies for timber, concrete and steel buildings are compared and the importance of sustainable material selection for buildings is highlighted. The results reveal that on average, the embodied energy of timber buildings is 28–47% lower than for concrete and steel buildings respectively. The mean and median values of embodied emissions are 2,92 and 2,97 for timber, 4.08 and 3,95 for concrete, and 5,55 and 5,53 GJ/m² for steel buildings. Moreover, the data suggests that the energy supply system of residential buildings plays a larger role in the operational energy consumption that the construction material. In addition, climate conditions, insulation detail, windows and building surfaces, and building direction are the other energy use role players. Finally, it was found that the demolition energy contributes only a small amount to the total life cycle energy consumption. This study demonstrates the significance of embodied energy when comparing the life cycle energy requirements of buildings and highlights the need for the development of a more standardised approach to LCEA case studies.

Urban areas have experienced exponential growth since the industrial revolution and by virtue, the urban population has followed. Current projections suggest that this growth has yet to reach its peak implying that urban developments will continue to sprawl into untouched territories. This growth and subsequent sprawl will undoubtedly come at the expense of forested areas. This study presents a carbon storage factor indicator for new urban developments. It is a novel concept which integrates urban planning, land use changes and wooden construction. The factor sets a carbon storage requirement for new urban areas that are developed at the expense of forested areas. The study is conducted in four parts. First, we estimate the carbon storage potential of forest areas via existing literature and databases. Then we collect all new development and construction estimates up to the year 2050 for the whole metropolitan region in Finland. Next, we conduct scenario analyzes for different demand levels of wood in projected residential developments. Finally, we compare the carbon storage potential of the future building stock to the forest areas planned for development. The data used is provided by the regional authority. The results detail that the future residential building stock can store between 128–733 kt of carbon. The lower level implies that current construction methods can only partially preserve the carbon storage of an area in buildings. However, the higher level suggests future buildings to be able to exceed the carbon storage potential of forest areas by nearly 47 tC ha⁻¹. The study reminds that an increased use of wood is dependent on sustainable forest management practices. Furthermore, it is not our purpose to promote urban development into entirely new areas but rather encourage urban planners to consider the carbon balance when it is the only viable option.

In Europe, buildings account for 40% of the energy consumption and produce 36% of CO₂ emissions. Renovation could be a great tool to decarbonize the building stock since it allows for a decrease in the operational energy required for buildings and is less material-consuming than new construction. Further benefits are brought by the usage of bio-based insulation materials that can drastically reduce embodied emissions and transform structures into factual carbon sinks. This study focuses on a particular kind of biogenic material, mycelium-wood composites, consisting of organic matter bound by the root structure of fungal organisms. This innovative insulation material was compared with traditional ones for the renovation of the building stock, with a focus on vertical components like walls in the Helsinki metropolitan area. To characterize mycelium-wood composites, density and carbon content information were gathered from the samples realized in the Politecnico di Milano MaBa.SAPERLab, while the production processes were included in a SimaPro model to obtain the GWP value. Different scenarios were then defined by two variables: the renovation rate of the building stock and the market penetration of mycelium-wood composites. For each scenario, the overall GWP and CO₂ stored values were calculated. Results show the great potential of the innovative material that grants carbon storage in the building stock that could even surpass the amount stored in the 32,500 ha of forest in the area. However, this possibility is heavily influenced by factors independent of the type of insulation used that should be further investigated.

Sustainable forest management and harvested wood products together can create a growing carbon sink by storing carbon in long-lived products. The role of wood products in climate change mitigation has been studied from several perspectives, but not yet from a consumer’s view. In this study, we examine the impact of wooden housing on consumer carbon footprints in Finland. We use the 2016 Finnish Household Budget Survey and Exiobase 2015, a global multi-regional input-output model. The sample size is 3700 households, of which 45% live in a wooden house. We find that residents of wooden houses have a 12(±3)% (950 kg CO₂-eq/year) lower carbon footprint on average than residents of non-wooden houses, when income, household type, education of the main income provider, age of the house, owner-occupancy and urban zone are controlled in regression analysis. This is not fully explained by the impact of the construction material, which suggests that the residents of wooden houses may have some features in their lifestyles that lower their carbon footprints further. In addition, we find that an investment in a new wooden house in an urban area has a strong reducing impact on a consumer’s carbon footprint, while investments in other types of housing have a weaker or no reducing impact. Our findings support wooden housing as a meaningful sustainable consumption choice.