This paper compares the environmental impact of the European residential stock as calculated with two LCA-based building stock models (Consumption Footprint – BoP Housing and PULSE-EU). The goal is to identify the purpose for which each model is best suited and to reflect on the need to balance modelling feasibility with accuracy, the uncertainties inherent to impact estimation at a large scale, and how they can affect policy support efforts. Whole life impacts are assessed first, followed by a separate analysis of operational and embodied impacts. To allow for an accurate comparison, the models are harmonised, leading to a partial scope adjustments, the selection of the same baseline year (2020) and the calculation of impacts using the indicators of the EN15804 + A2 standard. Discrepancies and commonalities are identified and their link to the characteristics of each model (such as granularity, archetype characterisation, and the approach used to model individual life cycle stages) is investigated. Crucial differences are identified in terms of modelling choices, particularly as it concerns background and foreground data selection, use of bottom-up and top-down data, upscaling parameters and the approach to emission timing. The results of the two models fall within the same order of magnitude for most indicators, though the percentage variation varies significantly. Operational impacts are higher in BoP Housing, and embodied impacts in PULSE-EU. These discrepancies are linked to different methodological choices. The study highlights the challenges associated with accurately estimating the environmental impact of a complex system such as the EU residential sector. The analysis reveals that both models have their strengths and weaknesses. Their coexistence can become instrumental in recognising the uncertainties inherent to this type of analysis, and provide a more nuanced interpretation of its results. BoP Housing, with its yearly updates, can track the evolution of the building sector over time; PULSE-EU, with its higher granularity, is well-suited to scenario analysis. In any building stock model, it is necessary to find an equilibrium between level of granularity and model flexibility. To reduce the uncertainties inherent to the models, it is important to promote data collection and accessibility within the EU. These uncertainties, however, can also be used to achieve a deeper understanding of the results obtained, leading to a more nuanced interpretation and a critical analysis of the way they are used in policy support.

The European Union aims to reduce greenhouse gas emissions by 55 percent by 2030 relative to 1990 and achieve climate neutrality by 2050. Yet, translating these targets into pathways for buildings and construction is challenging across diverse national contexts. We model building stocks for the twenty-seven Member States of the European Union and evaluate 4096 life cycle emissions scenarios, considering national capacities. Here we show that, over 2020-2050, achieving these targets would require avoiding 8.53 billion metric tons of carbon dioxide equivalent, approximately ten years of emissions at 2020 levels. Mostly relying on improving energy efficiency and material production would exceed national capacities by 2.72-billion-ton, 32 percent of the required reduction. A combined approach that also reduces per capita space demand, applies circularity measures, and uses bio‑based materials could achieve an additional 2.19 billion tons within national capacities. For each country, we identify the strategies that maximize projected reductions to inform policy design.

The uptake of renewable energy sources (RES) and recycled content (RC) in the manufacturing of nine construction materials is modelled at the material and building stock level, evaluating 19 environmental indicators with an LCA approach. The goal is to assess the effectiveness of these circular measures and gain insight into how different modelling approaches might affect the results. In the RES scenario, the impact reduction is similar for all assessed materials, while in the RC scenario it varies among the materials. This conclusion holds for the two modelling approaches used. The more detailed modelling approach revealed trade-offs between the environmental indicators, such as the increase in abiotic resource depletion impacts in the RES scenario. By adopting a consistent modelling approach and considering a broad range of impact categories, this work sets the foundations for comprehensive stock-level assessments of these measures, within the context of scenario analysis for policy support.

Storing atmospheric carbon dioxide (CO2) in products is identified as one of the key measures for carbon dioxide removal. The building sector and its potential use as a carbon sink is quickly becoming a consideration for active policies in Europe. However, while this remains a key element of informed decision-making, robust data on CO2 storage and uptake potentials vis-à-vis current greenhouse gas (GHG) emissions in the buildings sector is still lacking. Here, we quantify the carbon dioxide storage and uptake potentials for EU buildings in 2020 on three hierarchical levels: the material, building, and building stock level. We assess the potential of bio-based materials and mineral carbonation and compare the results to the baseline GHG emissions of the EU building stock. At the building level, bio-based materials show the largest storage effects. Carbonation during the use stage of buildings is smaller than in the end-of-life stage, yet both yield non-negligible effects that should be considered in life cycle assessments of buildings. However, when calcination emissions in the production stage are considered, the carbonation uptake of mineral materials does not lead to net removal of CO2 at the building level. At the building stock level, net biogenic carbon storage effects result in net storage equivalent to 1.27% of embodied GHG emissions, while mineral CO2 fluxes, including carbonation, result in net emissions equivalent to 10.16% of embodied GHG emissions in the EU-27 building stock in 2020. The results at the material, building, and building stock levels can be used as a comparative baseline for future net-zero GHG research in the European context.

As buildings are responsible for an important share of the energy use and related greenhouse gas (GHG) emissions in Europe, renovation of the building stock is a key priority in the coming decades. As these large-scale renovations will require a vast amount of materials, sustainable solutions for material use in renovations must be searched for. To date, the use of circular materials is put forward to reduce the embodied impact of building renovations. To get a better insight into the carbon footprint of building renovation using circular materials, the life cycle carbon footprint for these renovation solutions is studied in this paper. To avoid burden shifting, multiple impact categories have been assessed. For each element of the building envelope, a life cycle assessment (LCA) has been conducted of a renovation with conventional materials and four circular renovation measures, i.e., avoiding materials, using reclaimed materials, using recycled materials, and using bio-based materials. The results provide insight into the environmental benefits and burdens of these circular renovation approaches for single family houses in Flanders. This paper is expected to contribute to the debate on using circular strategies for renovation by highlighting their benefits and burdens.

The MIRACLE project pioneers the development of a radiative cooling material, for the first time based on conventional concrete. The photonic meta-concrete (PMC) aims at having great potential in reducing urban heat island effects, building energy use, and global climate change mitigation, while offering lower upfront embodied emissions compared to state-of-the-art passive daytime radiative cooling materials. This study assesses the full life cycle of integrating six final PMC compositions onto a conventional Belgian flat and pitched roof. Single score life cycle embodied environmental impacts are assessed assuming a 60-year service life. The results reveal significant variations in environmental impact based on roof type and PMC composition. For pitched roofs, replacing conventional concrete tiles with the environmentally best performing PMC composition results in negligible environmental impact changes. Flat roofs show higher impacts due to the additional layer of PMC being applied on top of the existing structures. Micro additions in some of the PMC compositions significantly influence the material upfront impact, increasing maintenance and replacement impacts as well. The environmentally worst-performing composition increases the impact of the roof buildup by up to 18 times for pitched roofs and 15 times for flat roofs. The best-performing materials result in a 7

A photonic meta-concrete (PMC), a radiative cooling material based on conventional concrete, is under development. This material reflects solar radiation through its high albedo and emits heat as longwave radiation via the atmospheric window, achieving effective cooling. This study assesses the PMC's impact on the urban heat island (UHI) in Belgian cities using the COSMO-CLM regional climate model with the TERRA_URB urban surface parametrization, simulating a 5-day heatwave across Flanders with 1 km horizontal grid spacing. Additionally, the study estimates radiative forcing from PMC application through a radiation scheme and translates this into CO2equivalent emission reduction. The results indicate that PMC reduces the UHI in Brussels, lowering daily surface and nightly 2m air temperatures by 9.6 degrees C and 2.7 degrees C respectively, due to the material high albedo. Scenarios with varying PMC coverage ratios show a non-linear relationship between coverage and temperature reduction, where lower coverage yields smaller cooling effects. Applying PMC to all urban roofs results in a radiative forcing reduction of 69.7 W/m2, equivalent to 22 kt of potential reduced greenhouse gas emissions. Although full PMC coverage on urban rooftops may be challenging, these findings underscore the material's potential for UHI mitigation, offering substantial cooling benefits and greenhouse gas reductions in large-scale applications.

In the context of the European Green Deal, achieving a climate-neutral building stock by 2050 has become a key objective. The 2024-revision of the Energy Performance of Buildings Directive (EPBD) highlights this goal by requiring EU Member States to transform their long-term renovation strategies into practical National Renovation Plans. The LIFE project GreenRenoV8 supports the practical implementation of the EPBD by developing a scalable, cost-effective methodology for deep, sustainable building renovation. By combining the environmental performance with the economic implications (both investment and life cycle cost), the project aims to identify the most cost-effective renovation strategies. GreenRenoV8 focuses on five EU Member States: Austria, Belgium (Flanders region), Greece, Italy and Slovenia. A stock modelling approach is used, starting with the identification of representative building archetypes per country. For each archetype, specific renovation strategies are developed and their life cycle environmental impact, investment cost and life cycle cost are assessed. The results are extrapolated to the national level to determine the most cost-effective measures and to prioritiže these. The modelling moreover incorporates seismic resilience where required. This paper describes the approach taken within the GreenRenoV8 project to support evidence-based renovation planning that maximižes environmental impact reduction and cost-effectiveness across the EU.

Addressing global warming through the modernization of buildings and urban areas is a major challenge. Passive daytime radiative cooling (PDRC) materials offer potential solutions, but none have effectively replaced concrete's dominant role in urban environments. Here, a Roman-inspired concrete with PDRC capabilities is presented, combining high solar reflectance (≈0.95) and long-wave infrared (LWIR) emittance (≈0.91). It delivers cooling powers over 45 W m- 2 under average solar intensities of 850 W m- 2 without a convection shield. On hot days (above 30°C), it stays 2°C cooler than the surrounding air under solar irradiance up to 985 W m- 2. Simulations predict this concrete can reduce energy use and CO2 emissions by ≈50% in hot regions and lower urban surface temperatures by up to 10°C during heat waves. This breakthrough offers a cheap, scalable and sustainable solution for energy efficiency and climate resilience.

Uncertainty remains a significant challenge in life cycle assessment (LCA), despite the availability of comprehensive models and databases. Addressing this requires tailored uncertainty and sensitivity analysis methods, such as parameter variation, scenario analysis, and Monte Carlo simulations. This study assesses the uncertainty and sensitivity of the environmental impact of ten daytime radiative cooling (RC) materials, contributing to the development of a novel cementitious-based RC material within the MIRACLE project. The study investigates three key sources of input uncertainty: (1) parameter sensitivity, analyzing variations in production processes; (2) Monte Carlo analysis, assessing uncertainty within Ecoinvent datasets used for RC material modeling; and (3) pedigree matrix evaluation, incorporating an additional layer of uncertainty where data are incomplete. The sensitivity analysis reveals that sputtering rate and pumping power significantly impact the environmental footprint of RC materials. Doubling the pumping power doubles the environmental impact, while the lowest sputtering rate increases the impact by over 600

The decarbonization of the built environment is critical to achieve climate neutrality by 2050, as existing buildings are responsible for over one-third of global energy use and GHG emissions. While traditional building stock analyses mostly rely on aggregated archetype models, this study develops and applies a bottom-up, building-by-building Life Cycle Assessment framework to assess the carbon footprint of building stocks at neighbourhood level. This approach integrates detailed environmental impact quantification with Geographic Information Systems (GIS), enabling spatial visualization and identification of carbon emission hotspots. To demonstrate the framework, a case study of 100 terraced houses in Leuven, Belgium, is conducted. Cradle-to-grave embodied and operational climate change impacts are quantified for the building envelope elements (external walls, roofs, floor on grade, and external windows) over a 60-year reference period. The results are compared to Flemish climate change benchmarks and disaggregated by element type, such as external walls, roofs, and windows. Results show that operational energy dominates the overall building stock impacts (nearly 90% of GHG), while external walls, floor on grade, and external windows account for 87% of embodied GHG. The most recent buildings achieve up to a 58% reduction in life cycle GHG compared to pre-1945 stock, despite rising material impacts. GIS mapping reveals spatial hotspots of poor performance concentrated in pre-1990 buildings. This spatially detailed approach offers policymakers and practitioners precise insights for prioritizing renovations strategically, optimizing thermal performance while preserving existing high-embodied-carbon elements.

The environmental effects associated with buildings are significant and include considerable contributions towards global greenhouse gas emissions, energy use, and waste generation. Until recently, mitigation efforts have concentrated on improving the operational energy efficiency of buildings, largely ignoring embodied environmental effects. However, focusing solely on increasing energy efficiency can inadvertently cause an rise in embodied effects. It is therefore critical that embodied effects are considered alongside operational effects and are actively integrated into design decisions throughout the building design process. Life cycle assessment (LCA) can be used to achieve this, however, it is often perceived as difficult to incorporate into design workflows, or requiring specialist knowledge. Additionally, it is not always clear how well aligned LCA approaches are with the building design process. To address this gap, this study aims to provide a detailed analysis of LCA approaches, to assess how well they align with building design stages, and to identify key characteristics, including LCA tools and environmental data used to conduct assessments. A review of academic and grey literature is conducted. Three primary approaches are identified for integrating LCA into the building design process: simplified, detailed and incremental LCA. Simplified LCA uses streamlined data inputs and typically targets a specific design stage. Detailed LCA follows a traditional approach with comprehensive user inputs and results. Incremental LCA progressively evolves the assessment based on design requirements and available building data at each design stage. An analysis of each approach is performed, and key user requirements are mapped against the early design, and detailed design stages. Results reveal that no single approach fully satisfies all design requirements. Findings also highlight a lack of incremental LCA approaches and challenges operationalising these techniques. These approaches often rely on complicated methods or tools not suitable for common design workflows, or they are in early development and require additional verification before implementation.

Building construction and operation are responsible for around 40 % of global energy-related greenhouse gas emissions. To identify emissions reduction and removal potentials as well as wider environmental impacts, researchers, policy, and decision makers need comprehensive life cycle sustainability assessment (LCSA) insights on individual buildings and building stocks at large. This article proposes an open building data model for Scalable, high-definition Life Cycle Engineering (SLiCE) as a solution to overcome the limitations identified for existing models. The article departs from conceptualizing the problem within the Space-Time-Indicator Nexus; presents the proposed SLiCE data structure; and showcases practical uses of SLiCE data for dynamic assessment of climate change impact as well as for systematic environmental hotspot analysis. The open SLiCE building data model and SLiCE hotspot analysis tool are henceforth available for implementation within life cycle assessment (LCA) of building and building stocks, enabling comprehensive insights on buildings' environmental impacts across spatiotemporal scales.

PurposeThe aim is to holistically assess the environmental performance of windows and analyse how their design and characteristics contribute to the overall performance of the building/space. This study focuses on the performance of windows in patient rooms hosting less mobile people.Design/methodology/approachThis study investigates the life cycle environmental impacts of different glazing types, window frames and fire safety doors at the product level. This article also presents a building-integrated environmental analysis of patient rooms that considers the multiple functionalities of windows by incorporating dynamic energy analysis, comfort and daylighting performance with a life cycle assessment (LCA) study.FindingsThe results indicate that the amount of flat glass is the main contributor to the environmental impacts of the glazing units. As for the patient rooms, global warming shows the most significant contribution to the environmental costs, followed by human toxicity, particulate matter formation and eutrophication. The key drivers for these impacts are production processes and operational energy use. This study highlights the significance of evaluating a wide range of criteria for assessing the performance of windows.Originality/valueAn integrated assessment approach is used to investigate the influence of windows on environmental performance by considering the link between window/design parameters and their effects on energy use/costs, daylighting, comfort and environmental impacts. The embodied impacts of different building elements and the influence of various design parameters on environmental performance are assessed and compared. The environmental costs are expressed as an external environmental cost (euro).

By the end of 2050, it is expected that 68

Environmental benchmarks are a means to stimulate lowering environmental impacts of buildings. These benchmarks may be based on a bottom-up or top-down approach. While bottom-up benchmarks are derived from the analysis of reference buildings and represent current building practice, staying within the Earth's carrying capacity requires top-down benchmarks representing long-term environmental goals. Top-down benchmarks are derived by allocating a share of the global carrying capacity to objects, e.g. buildings, using so-called sharing principles. Various sharing principles exist, which significantly influence benchmark values. This study applies a wide range of sharing principles, including novel principles, to define top-down benchmark values for Belgian residential buildings based on global carrying capacities. An environmental budget was first allocated to Belgium, then to households and finally to the housing function. In each step, multiple sharing principles were applied, resulting in 32 combinations of sharing principles. For a single-person household, the minimum and maximum budget resulting from the combinations differ by a factor 42. Based on data availability and quality as well as ethical considerations, the authors of this paper give preference to "right to development" for the allocation to Belgium; "household composition" for the allocation to households and "final consumption expenditures" for the allocation to the housing function. The comparison of the top-down benchmark values with bottom-up benchmarks reveals that various measures are required to remain within the Earth's carrying capacity. The top-down benchmark values presented in this paper can hence guide policymakers in establishing environmental targets and related roadmaps for residential buildings in Belgium.

As the European Union (EU) is aiming to realize climate neutrality by 2050, there is a need to investigate greenhouse gas (GHG) reduction and carbon dioxide removal strategies (CRRS) from a life cycle perspective. Existing literature lacks harmonization of building-related strategies considering the whole-life cycle of buildings and the interlinkages across life cycle stages. The aim and novelty of this study was to systematically identify, classify and quantify the impacts of CRRS, as well as assess their applicability in different EU Member States. We identified a total of 35 measures grouped in 11 CRRS for the whole-life cycle of buildings. We classified these measures according to various criteria, such as the avoid–shift–improve framework or the life cycle stages influenced. We then assessed the potential diffusion of these strategies in each EU Member State up to 2050 via qualitative assessment criteria. We could achieve notable short-term reductions in GHG emissions by improving use-phase energy use, selecting low-carbon materials or reducing the per capital space demand. In the medium to long term, the applicability and reduction potential of strategies such as circularity and prioritizing renovation over new construction will increase as supply chains and skills develop across the EU. Due to their different potentials and times of implementation, the entire range of strategies is needed to support building and construction transition efforts.

Abstract The building sector plays an important role in achieving the climate objectives of the EU Green Deal. While prioritizing measures to reduce operational energy and GHG emissions has proven beneficial, it has shifted burdens by increasing embodied emissions. Quantifying and regulating emissions throughout the entire building life cycle is therefore crucial. An ongoing DG GROW project is investigating strategies to reduce life cycle GHG emissions within the EU. Various steps are being carried out to achieve the research goals: identification of data needs and sources, baseline analysis of the existing whole life carbon emissions of the EU building stock, modelling of future scenarios. This paper elaborates on the building stock characterization, demonstrating innovation through its level of granularity. Firstly, key data sources are chosen to provide the desired granularity. Secondly, archetypes are defined based on the data sources. Thirdly, attributes are chosen to describe the building stock in terms of geometry, building element composition, energy use, etc. The paper concludes by discussing challenges related to collecting attribute information and managing data gaps. The insights derived offer valuable recommendations for establishing a future data repository dedicated to environmental LCA of the EU building stock.

Abstract The European Union (EU) aims at climate-neutrality by 2050, necessitating a transformation of the entire economy, including the construction and buildings sectors. This study, initiated by the European Commission’s DG ENV, provides a basis for a roadmap to mitigate building-related greenhouse gas (GHG) emissions from a life cycle perspective. This paper presents methodological developments and findings for the baseline year 2020. The research assesses whole life cycle (WLC) GHG emissions from European buildings, covering various archetype buildings. It supports the creation of an EU roadmap to reduce WLC GHG emissions by 2050. The study employed attributional LCA and five key steps: 1) Characterization of building stock based on four climatic regions; 2) Selection of representative archetypes; 3) Modelling of building life cycle inventories; 4) life cycle assessment using the GWP indicator; 5) Upscaling of building results to the building stock level. The results emphasize the relevance of reducing both operational and embodied GHG emissions at both the individual building and building stock level. At the level of individual new buildings with advanced energy performance, embodied GHG emissions average 66% of life cycle emissions, ranging from 43% to 97%. At stock level, embodied GHG emissions make up 21% of whole life cycle GHG emissions, even though only about 1% of building stock area is newly constructed in the baseline year. The remaining 79% of WLC emissions are coming from the operation of existing buildings. Within the embodied emissions, new building production and construction process stages account for 55%, existing building’s use phase embodied contributes another 20%, and refurbishment of the existing stock makes up around 15%, while end-of-life processes contribute only 2%. The study provides a novel perspective on GHG emission in the life cycle of buildings and building stocks. It lays the groundwork for an EU roadmap to reduce WLC GHG emissions. Outcomes will aid policy formulation, target setting, and implementation of suitable GHG emission reduction strategies.

To reduce the environmental effects caused by building construction and operation, life cycle assessment (LCA) is increasingly applied. In recent years, national building regulations have implemented LCA requirements to support building life cycle impact reduction. A key element in these regulations are environmental benchmarks which allow designers to compare their building designs with reference values. This study aims to develop bottom-up life cycle environmental benchmarks that represent the range of environmental impact results achieved with conventional construction in Flanders, Belgium. For this purpose, the study investigates the potential of using a database of building energy performance calculations. Specifically, this study considers 39 residential buildings identified as representative of the Flemish energy performance of buildings database of 2015–2016, applying modifications to establish scenarios that are still relevant in 2025. The buildings are assessed with the Belgian LCA tool TOTEM to calculate an aggregated environmental score based on the European product environmental footprint (PEF) weighting approach and including 12 main impact categories. In addition to the aggregated score, the climate change (CC) indicator is analysed individually. In view of the benchmarks, variations were applied to the 39 original buildings in terms of heating system and materialisation. The variation in heating system included changing gas boilers to electric heat pumps to comply with upcoming (2025) Flemish building regulations. The variations in building materials included three sets of conventional Flemish building element compositions that were applied to generate a wider spread of impact results as a basis for benchmarks. Benchmark values were derived through a statistical analysis of the 117 modelled variants: a best-practice value (10th percentile), reference value (median) and limit value (90th percentile). For the environmental score, the benchmark values are 86, 107 and 141 millipoints per square meter of gross heated floor area (GHFA) (mPt m ^−2 GHFA), respectively; and for CC, the benchmark values are 844, 1015 and 1284 kg CO _2 -eq m ^−2 GHFA. Finally, the study discusses the representativeness, implications and limitations of the final benchmarks and benchmark approach.