Evaluating novel building products through a building design-oriented LCA approach: Example of VIPs in terrace applications

Content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Ltd World Sustainable Built Environment 2024 IOP Conf. Series: Earth and Environmental Science 1363 (2024) 012067 IOP Publishing doi:10.1088/1755-1315/1363/1/012067 1 Evaluating novel building products through a building designoriented LCA approach: Example of VIPs in terrace applications D. Božiček1, M. Košir1, J. Zach2, V. Novák2, J. Peterková2, J. Bubeník2, A. Lešek3, S. Jordan3 and K. Malovrh Rebec3 1University of Ljubljana, Faculty of Civil and Geodetic Engineering, Jamova cesta 2, SI-1000 Ljubljana, Slovenia 2Brno University of Technology, Faculty of Civil Engineering, Institute of Technology of Building Materials and Components, Veveří 331/95, 602 00 Brno, Czech Republic 3Slovenian National Building and Civil Engineering Institute, Dimičeva ulica 12, SI1000, Ljubljana, Slovenia Corresponding author: [email protected] Abstract. INTRODUCTION: The construction industry is considered conservative in adopting new products/ technologies, and environmental characteristics are one of the most important features of novel solutions. In this context, our study aims to present a building design-oriented assessment of a novel building product by extending the functional unit scope and involving multiple realistic building design scenarios. The task will be performed using the example of vacuum insulation panels (VIPs), a superinsulation product that can be used in various building applications. The study will focus on terrace insulation applications, where VIPs are an attractive solution for building designers due to the possibility of barrier-free floor design. However, they lack environmental evaluation. METHOD: A life cycle assessment (LCA) analysis is performed on two hypothetical buildings located in Ljubljana (Slovenia) for the cradle-to-gate and operational energy life cycle stages (A1-A3 + B6 according to EN 15978). A whole-year dynamic thermal response simulation was executed using the Design Builder software. Five barrier-free terrace design scenarios that influence the embodied and operational carbon footprint (while maintaining the functional and architectural integrity of the building design) were examined. RESULTS: The study showed that although EPS insulation showed a smaller embodied carbon footprint on the product level, the building level analysis showed that using VIPs in terrace applications leads to favourable or comparable environmental impact. CONCLUSIONS: Building products can be evaluated on three functional unit levels: product, application and building. By extending the boundaries from the product/application level to the entire building level, the study provides an example of a building design-oriented approach to LCA. The complexity increases by upgrading the functional unit scope to the building level, while the results become more case-specific and less general. Ideally, a novel building product should show environmental superiority on all three levels. However, as there are almost countless design possibilities in buildings, environmental superiority (or inferiority) on the product level does not necessarily indicate superiority (or inferiority) on the building level. World Sustainable Built Environment 2024 IOP Conf. Series: Earth and Environmental Science 1363 (2024) 012067 IOP Publishing doi:10.1088/1755-1315/1363/1/012067 2 SYMBOLS AND ABBREVIATIONS U-value [W/(m2K)] thermal transmittance LCA life cycle assessment λ [W/(mK)] thermal conductivity EPD environmental product declaration ρ [kg/m3] density GWP [kg CO2 eq.] global warming potential EPS expanded polystyrene RSP reference study period XPS extruded polystyrene Acon. conditioned area VIP vacuum insulation panel COP coefficient of performance WWR window-to-wall ratio 1. Introduction After 2023 being the warmest year in recorded history [1], the urge to reduce global greenhouse emissions is more evident than ever. In addition to (or concurrently with) climate change, many environmental problems are raising concerns and questions on how to address them [2]. Buildings play a vital role in society. However, their construction and upkeep require materials and energy. Buildings are responsible for almost 40 % of anthropogenic greenhouse gas emissions, of which 10 % are contributed by the building materials industry and the remainder by operational energy needs [3]. The construction sector extracts vast resources from the global economic stream [4]. Consequently, reducing buildings' embodied and operational environmental impacts could mitigate the extent of the pressure on the environment [5], [6]. Although reducing the environmental impact in buildings is a multifaceted challenge that requires different strategies [7], the design decisions regarding the chosen building products are essential for optimising the environmental impact. Therefore, novel building products introduced to the market must show environmental benefits while providing equivalent technical performance. Through the development of life cycle assessment (LCA), it has become possible to evaluate the environmental performance of building products and buildings, enabling the comparison of various alternatives. LCA is recognised as a tool for calculating the environmental impact through the life cycle of products and services [7]. It plays an essential role in reducing the embodied impacts of buildings, with many countries implementing voluntary or mandatory carbon footprint calculation frameworks [8]. Building LCA is increasingly enabled by extending the LCA database for building products through environmental product declarations (EPDs) [9]. EPDs are documents which communicate LCA data [10], which, according to building LCA standards (EN 15978 [11], ISO 21931-1 [12]), can be used for calculating the embodied impacts of buildings. The number of EPDs is increasing, and over 16000 verified EPDs produced following relevant standards (ISO 14025 [13] and EN 15804 [14], [15]) exist [16]. Building LCA development has enabled comparing how different design decisions influence environmental performance [17]. In addition to being a tool for building designers, LCA can also be useful for developing novel building products and technologies. However, evaluating and comparing the environmental performance of a building solution can be challenging. The reason is that buildings are complex systems, and various design options are possible [18]. Determining the LCA study scope and its functional unit can significantly influence the LCA results. As building products are designed to be used in building applications, multiple scenarios for comparison are often possible. 1.1. Study goal and description This study aims to illustrate the challenge of evaluating the environmental impact of novel building products in building applications. To better illustrate the complexity of evaluating building design solutions, an LCA study on various terrace design solutions will be performed. The LCA study aims to compare multiple design solutions using vacuum insulation panels (VIPs) and conventional insulation. This will be done for two theoretical buildings, differing in geometry, size and terrace-to-conditioned floor area ratio. World Sustainable Built Environment 2024 IOP Conf. Series: Earth and Environmental Science 1363 (2024) 012067 IOP Publishing doi:10.1088/1755-1315/1363/1/012067 3 The study was motivated by a literature review of life cycle studies of VIPs in building applications, where past research on VIPs' environmental and economic performance was analysed [19]. It was found that VIP terrace applications were not yet the focus of LCA studies, which makes this study the first of this kind. However, the main focus is not to provide a detailed evaluation of VIPs in terrace applications. Therefore, the LCA study scope will be simplified. The study will focus solely on the carbon footprint presented by the global warming potential (GWP) indicator. The system boundaries will be limited to the production (A1-A3) and operational energy demand (B6) life cycle stages. These stages represent the embodied (A1-A3) and operational (B6) carbon footprint. The LCA study of various terrace design solutions will provide an example of a building designoriented evaluation of a novel product (VIPs) compared to conventional solutions. Based on this example, it will be shown how the LCA results can change if the functional unit develops from the product to the whole building level. Based on our experience and knowledge, this is the first attempt to underline the importance of the functional unit in evaluating the environmental performance of building products. Section 2 briefly describes VIPs in building applications and the advantages of VIPs in terrace applications compared to conventional insulation materials. The methodology section (section 3) presents the specifics of the LCA study and energy simulation. Additionally, the limitations of the study are described. Section 4 provides the results, focusing on the carbon footprint, with additional results in the appendices. Following the results section is the discussion (section 5), where the challenges and specifics of comparing building products will be elaborated based on the calculated results. A framework for comparing the environmental impact of building products will be presented and elaborated. Finally, the conclusion section (section 6) provides a brief study outline and underlines the main findings. 2. Problem clarification – VIPs in building applications 2.1. What are VIPs? Vacuum insulation panels (VIPs) are specific thermal insulation products classified as superinsulation materials [20]. They are composite materials with a core wrapped in an airand vapour-tight barrier envelope. Various open porous materials can be applied (e.g. open-cell polyurethane [21], aerogel [22]). However, fumed silica is the most commonly used core material for building applications [23], for which various products exist (Figure 1). Due to their superior thermal properties, VIPs were perceived as having considerable potential for building applications [24]. According to published data, the effective thermal conductivity for fumed silica VIPs with a service life of 25 years ranges from 0.007 to 0.009 W/(mK) [25]–[27], whereas the centre of panel thermal conductivity can be less than 0.0045 W/(mK). However, although VIPs have been commercially available for over a decade and can be categorised as advanced insulation materials [28], their market share in building applications is negligible (below 1 %) [29]. According to 2014 data, 10 % of the global VIP production was intended for building applications, whereas the remaining 30 % was used for transportation boxes and 60 % for refrigerators [23]. Due to their small market share and continuing development, VIPs will still be considered novel building products in this study. The main disadvantages of VIPs compared to conventional building insulation materials are higher costs [30], sensitivity to damage on the construction site [31], [32], inability to adapt their size on the construction site [33], challenges with on-site installation [30] and concerns regarding their service life [33]. Some of the stated disadvantages are partially solved by developing specific products with protective sheeting (Figure 1). World Sustainable Built Environment 2024 IOP Conf. Series: Earth and Environmental Science 1363 (2024) 012067 IOP Publishing doi:10.1088/1755-1315/1363/1/012067 4 Figure 1: Components for a fumed silica core VIP (top left) [24] and a polyurethane sheet-protected VIP designed for terrace and roof applications (top right and bottom) [34]. 2.2. What life cycle studies on VIPs in building applications showed? The study conducted by Božiček et al. [19] evaluated the environmental and economic performance of VIPs in building applications. They found that VIPs can be used in over 10 building applications, ranging from various building envelope positions (roof, walls, floors) to specific positions/ systems (e.g. shading shutters, dormer windows, doors). However, the main focus of life cycle studies were external wall applications (over 70 % of studied applications). Most studies showed that based on a direct comparison with conventional insulation materials (mineral wool, polystyrene), fumed silica VIPs show higher environmental impact if the comparison is based on an equivalent thermal performance (i.e. equal U-value). The authors suggest additional studies to evaluate the missing building applications and scenarios where the applications of VIPs could potentially show energy and material demand-related benefits. Such an approach is demonstrated through studies evaluating the economic feasibility of VIPs, where the added benefit of increased floor space was included [35], [36]. A more holistic approach is suggested, where the study is not focused purely on the products but also includes building design-oriented scenarios and energy use and material implications resulting from the application of VIPs. 2.3. VIPs in terrace applications – building design-related implications Based on the findings outlined above, we explore to evaluate VIPs in terrace applications and how the application of VIPs influences the building design compared to conventional insulation materials. The study scope will expand beyond the terrace to include the material and energy-related consequences on the building level. World Sustainable Built Environment 2024 IOP Conf. Series: Earth and Environmental Science 1363 (2024) 012067 IOP Publishing doi:10.1088/1755-1315/1363/1/012067 5 A barrier-free terrace access is necessary for providing universally accessible spaces (e.g., wheelchair access) and, therefore, a requirement in many building types (e.g., hospitals, elderly care facilities, hotels, and educational buildings). However, when the terraces are located above conditioned spaces, the energy efficiency requirements can dictate low thermal transmittance levels, which require over 15 cm thick conventional insulation layers (e.g., expanded or extruded polystyrene). Therefore, the main advantages of using VIPs in such applications are their superior thermal conductivity and the consequential lower thickness of the assembly. Consequently, design and construction-related problems can be avoided by applying VIPs in barrier-free terraces, where the two main problems are; • Stair design: A thick external terrace insulation layer in multiple-floor buildings can increase inner floor thickness due to added screed/acoustic insulation layers. Besides the additional floor expenses, this can impact the staircase design. The stair profile (i.e. number of steps, elevation, height, etc.) can be influenced, complicating the building design. • Floor-to-ceiling height: Terraces above conditioned spaces require thick insulation layers of conventional materials (e.g. polystyrene, mineral wool). This results in either applying thick internal layers (ceiling insulation) or lowering the terrace load-bearing structure to compensate for the mismatch in thicknesses between external and internal floor components, leading to undesirable design and construction-related problems. From the stated point of view, applying VIPs in barrier-free terraces above conditioned spaces can simplify the building design. Besides design and construction-related simplifications, applying VIPs can also show economic and environmental benefits, as it reduces the need for additional materials in walls and floor layers to compensate for the terrace insulation layers and provide minimal floor-to-ceiling height. Compared to conventional solutions, this study will evaluate how the application of VIPs in a barrier-free terrace influences the building's embodied and operational carbon footprint. 3. Methodology The analysis will consider two theoretical buildings (Figure 2). Their geometry is built upon a modular unit with fixed internal size: length = 3.6 m; depth = 5.5 m; height = 2.8 m. Building A consists of three modules and presents a building with a large terrace-to-conditioned floor area ratio (i.e. 100 % of roof area and 33 % of conditioned area). Building B presents a larger building with an identical terrace, resulting in a smaller terrace-to-conditioned floor area ratio. The building consists of 39 modules, where the terrace presents 5 % of the roof area and 2.5 % of the conditioned area. Two extremes were evaluated by choosing this geometry configuration, presenting buildings with large and small terrace areas concerning the conditioned spaces. The share of the terrace area in building B is the limit value, for which less strict envelope insulation levels apply according to Slovenian building energy efficiency regulations [37]. According to it, terraces that present less than 5 % of roof area require a U-value of 0.6 W/(m2K), whereas for larger shares, the U-value is 0.15 W/(m2K) – the same as for roof assemblies. World Sustainable Built Environment 2024 IOP Conf. Series: Earth and Environmental Science 1363 (2024) 012067 IOP Publishing doi:10.1088/1755-1315/1363/1/012067 6 Five terrace design solutions will be evaluated (Figure 3). The first presents a terrace with a 5 cm VIP layer providing a surface-to-surface U-value of 0.15 W/(m2K). The second one presents a solution where the 5 cm VIP layer is replaced by a 5 cm expanded polystyrene (EPS), resulting in a surface-tosurface U-value of 0.53 W/(m2K). Solutions from 3 to 5 present variations of design solutions that compensate for the 22 cm EPS layer necessary for a surface-to-surface U-value of 0.15 W/(m2K). Solution 3 applies a height-adjusted terrace load-bearing structure, and solutions 4 and 5 apply adjusted internal floor layer thicknesses. More detailed compositions and thermal properties are presented in sections 3.1 and 3.2. Figure 3:Schematic presentation of evaluated terrace design solutions. Building A – large terrace share Building B – small terrace share Figure 2: Buildings geometries for evaluating the impact of applying VIPs in barrier-free terrace aplications. World Sustainable Built Environment 2024 IOP Conf. Series: Earth and Environmental Science 1363 (2024) 012067 IOP Publishing doi:10.1088/1755-1315/1363/1/012067 7 3.1. LCA: scope, scenarios and data The goal was to construct an LCA study that identifies the environmental-related consequences of VIPs in terrace applications and compares them with possible terrace design solutions applying conventional insulation (EPS). The LCA analysis focuses on the building materials (quantity) and the energy demand for heating (Table 1). The considered reference study period (RSL) is 25 years. The system boundaries include production (A1-A3) and energy demand for operations (B6) life cycle modules (A1-A3 + B6, according to EN 15978 [11]). According to EN 14805+A2 [15], four GWP indicators are used to present the impact on climate change: GWPtotal, GWPfossil, GWPbiogenic and GWPluluc. To simplify the interpretation of the carbon footprint results, we chose only GWPfossil. This indicator primarily presents the greenhouse gas emissions originating from the use of fossil fuels. The functional unit is the theoretical building (buildings A and B) for which the evaluation is performed. The materials in the floors, walls and roof are included in the production life cycle stages. The selected materials for the analysis and the assembly compositions reflect material in a real-world building design, where VIPs were used in barrier-free terrace applications. Based on experience from previous LCA studies, we included only those building materials which contribute significantly to the bill of quantity and embodied carbon footprint (GWPfossil). Therefore, we excluded waterproofing layers, various membranes (e.g., vapour barrier), internal finishing layers and others (see Table 2 for the list of materials included in the LCA calculations). Five scenarios were evaluated for each building type (A and B), presenting the considered terrace design solutions (Figure 3 and Table 1). These scenarios are highly building design-oriented, as the decision regarding the type of terrace insulation (VIP or EPS) and its thickness influence the building design. For the scenario comparison, it is assumed that the comparison considers a minimal floor-toceiling height of 2.8 metres for all scenarios. Therefore, any changes that influenced this dimension were compensated for by an increased wall height (i.e. solutions 3 to 5). Solution 3 presents an option to provide barrier-free terrace access by lowering the terrace load-bearing structure. Consequentially, this leads to a lowered floor-to-ceiling height under the terrace, resulting in the need to increase the overall height of the walls. Solution 4 presents a variant in which the terrace insulation thickness is compensated by applying thicker screed/ acoustic insulation layers. Although using such a thick acoustic layer is not realistic, we chose this option as its embodied impact on the m2 of floor area is lower than by using thicker layers of cement screed (i.e. we chose the environmentally less impactful option). Solution 5 represents an elevated floor system variant that can be constructed with various materials/systems (e.g. various options for substructure including pedestals [38]). We assumed a wooden substructure (battens on 25 % of the floor area and a deck with OSB boards) and kept the base case acoustic layer and screed thickness. Table 2 presents the relevant LCA data for executing the calculations. The LCA data for materials is sourced from EPDs. The GWPfossil value for VIPs represents average values from three EPDs and additional data published by Resalati et al. [39]. Only EPDs from ECO Platform members [40] were included. Also, a geographical limitation was applied to exclude data from unrealistic sources for the Slovenian building market (e.g., concrete produced in Scandinavian countries). Data for the operational emissions of natural gas were sourced from the One Click LCA software library [41]. World Sustainable Built Environment 2024 IOP Conf. Series: Earth and Environmental Science 1363 (2024) 012067 IOP Publishing doi:10.1088/1755-1315/1363/1/012067 8 Table 1: Study scope and the evaluated scenarios. SYSTEM BOUNDARIES (per EN 15978) Production: A1, A2, A3 Heating energy for operation: B6 (RSP 25 years) ENVIRONMENTAL INDICATORS: GWPfossil [kg CO2 eq.] FUNCTIONAL UNIT Building A and Building B (respectively). A1-A3 - INCLUDED (see Table 3): - ground floor - external walls, - internal floor. - roof and terrace. A1-A3 - EXCLUDED: - internal walls - HVAC systems, - plumbing installations, - windows and doors, - waterproofing layers, - floor, wall and ceiling finishes, - stairs, etc. EVALUATED SCENARIOS (see Figure 3 for visual presentation) SOLUTION 1 – base case (VIP) The base case for material quantity and heating demand calculations. The terrace design difference and material/energy-related consequences of other solutions are described in relation to the base case. SOLUTION 2 Identical building geometry and material quantity as the base case. DIFFERENCE: VIP insulation layer changed for EPS layer with identical thickness (5 cm). CONSEQUENCE: Impact on heating demand (B6). SOLUTION 3 Height-adjusted terrace load-bearing structure to compensate for the 22 cm thick EPS insulation layer. DIFFERENCE: VIP insulation layer changed to a 22 cm EPS layer, and the terrace loadbearing structure was lowered by 17 cm. CONSEQUENCE: Increased wall height of the ground floor by 17 cm. SOLUTION 4 Increased thickness of internal floor layers to compensate for the 22 cm thick external EPS layer and provide barrier-free terrace access. DIFFERENCE: Acoustic insulation layer thickness increased from 5 to 22 cm. CONSEQUENCE: Increased demand for acoustic insulation material and increased wall height (by 17 cm) for the second floor. SOLUTION 5 Increased height of the internal floor finishing layer to compensate for the 17 cm thicker terrace insulation layer and provide barrier-free access. DIFFERENCE: Application of a wooden substructure consisting of wooden battens and OSB deck boards. CONSEQUENCE: Additional wood materials (battens and OSB board) and increased wall height by 17 cm for the second floor. Table 2: LCA data of materials and fuel (natural gas) for embodied and operational carbon footprint calculations. Material group declared unit λ [W/mK] ρ [kg/m3] GWPfossil [kg CO2 eq.] 1. concrete C25/30 m3 2.3* 2400 197.00 2. reinforcement (rebar/ mesh rebar) kg 7850 0.65 3. cement screed kg 2.0 2000 0.17 4. XPS m3 0.033 34.3 102.07 5. EPS_ETICS m3 0.035 18.1 52.95 6. mineral wool m3 0.035 100 116.07 7. EPS_terrace m3 0.035 26.5 77.28 8. VIP (10 mm) m2 0.008 180 19.52 9. wood (sawn/dried) m3 0.13 486.8 28.90 10. OSB board m3 0.13 607.2 174.06 OPERATION (B6) - fuel 1. Natural Gas declared unit GWPfossil [kg CO2 eq.] kg CO2 eq./kWh 0.25 * for reinforced concrete World Sustainable Built Environment 2024 IOP Conf. Series: Earth and Environmental Science 1363 (2024) 012067 IOP Publishing doi:10.1088/1755-1315/1363/1/012067 9 3.2. Energy Simulation: building and simulation input data The energy demand for the considered buildings is going to be calculated using a dynamic thermal response simulation using the Design Builder software (version 5.5.0.012) [42], which is built upon the EnergyPlus [43] simulation framework. The energy demand is calculated for the continental climate of the capital city of Slovenia, Ljubljana (Köppen-Geiger climate classification: Cfb). Figure 4 presents the building models in Design Builder with the considered orientation. The terrace is positioned on the south side of the building. Table 3 shows the building assembly compositions for all the considered envelope solutions. The thermal conductivity values of the materials considered are presented in Table 2. The primary input data for the energy simulations are shown in Table 4. One thermal zone per building is assumed. The chosen input data for temperature set-point, internal loads, lighting and ventilation reflect representative values for residential buildings. The schedules and values for occupancy, lighting and electric equipment were assumed according to the "TM59 Studio" activity template. An important factor for comparing thermal insulation materials is the considered thermal conductivity. We considered a value of 0.008 W/(mK) for VIPs and 0.035 W/(mK) for EPS insulation. Other values used to calculate the thermal transmittance of thermal envelope assemblies are presented in Table 2. Energy-efficient triple pane windows with PVC frames are assumed (surface-to-surface U-value for glazing 0.78 W/(m2K) and 1.00 W/(m2K) for the frame), with a window-to-wall ratio (WWR) of 15 %. Acon. = 52.4 m2 Acon. = 772.2 m2 Number of modules: 3 Number of modules: 39 Figure 4: Design Builder energy simulation models for building A (left) and B (right). World Sustainable Built Environment 2024 IOP Conf. Series: Earth and Environmental Science 1363 (2024) 012067 IOP Publishing doi:10.1088/1755-1315/1363/1/012067 16 [23] S. Brunner, K. Ghazi Wakili, T. Stahl, and B. Binder, "Vacuum insulation panels for building applications—Continuous challenges and developments," Energy Build., vol. 85, pp. 592–596, Dec. 2014, doi: 10.1016/j.enbuild.2014.09.016. [24] H. Simmler et al., "Vacuum Insulation Panels - Study on VIP-components and panels for service life prediction of VIP in building applications (Subtask A)," Sep. 2005, Accessed: Apr. 13, 2021. [Online]. Available: https://www.osti.gov/etdeweb/biblio/21131463 [25] Porextherm, "Technical data sheet Vacupor-ts-b2-s." Accessed: Dec. 09, 2022. [Online]. Available: https://www.morganthermalceramics.com/media/4116/vacupor-ts-b2-s-english.pdf [26] va-Q-tec, "Product data sheet - va-Q-F." Accessed: Dec. 09, 2022. [Online]. Available: https://va-q-tec.com/wp-content/uploads/pimcore/2022-10-13_%20Product-Data-Sheet_va-Q-FVersions.pdf [27] A. Holm and C. Sprengard, "Long-Term Performance of Super-Insulating-Materials in Building Components & Systems - Hygro-Thermo-Mechanical Properties and Ageing," Int. Energy Agency, p. 101, Spring 2020. [28] S. Schiavoni, F. D׳Alessandro, F. Bianchi, and F. Asdrubali, "Insulation materials for the building sector: A review and comparative analysis," Renew. Sustain. Energy Rev., vol. 62, pp. 988–1011, Sep. 2016, doi: 10.1016/j.rser.2016.05.045. [29] Joint Research Centre (European Commission), C. Pavel, and D. T. Blagoeva, Competitive landscape of the EU's insulation materials industry for energy-efficient buildings: revised edition. LU: Publications Office of the European Union, 2018. Accessed: Nov. 23, 2022. [Online]. Available: https://data.europa.eu/doi/10.2760/750646 [30] M. Gonçalves, N. Simões, C. Serra, and I. Flores-Colen, "A review of the challenges posed by the use of vacuum panels in external insulation finishing systems," Appl. Energy, vol. 257, p. 114028, Jan. 2020, doi: 10.1016/j.apenergy.2019.114028. [31] A. Uriarte, I. Garai, A. Ferdinando, A. Erkoreka, O. Nicolas, and E. Barreiro, "Vacuum insulation panels in construction solutions for energy efficient retrofitting of buildings. Two case studies in Spain and Sweden," Energy Build., vol. 197, pp. 131–139, Aug. 2019, doi: 10.1016/j.enbuild.2019.05.039. [32] M. J. Tenpierik, J. J. M. Cauberg, and T. I. Thorsell, "Integrating vacuum insulation panels in building constructions: an integral perspective," Constr. Innov., vol. 7, no. 1, pp. 38–53, Jan. 2007, doi: 10.1108/14714170710721287. [33] R. Baetens et al., "Vacuum insulation panels for building applications: A review and beyond," Energy Build., vol. 42, no. 2, pp. 147–172, Feb. 2010, doi: 10.1016/j.enbuild.2009.09.005. [34] "Deck-VQ® | Recticel Insulation." Accessed: Dec. 20, 2023. [Online]. Available: https://www.recticelinsulation.com/en-gb/deck-vq [35] N. Simões, M. Gonçalves, C. Serra, and S. Resalati, "Can vacuum insulation panels be costeffective when applied in building façades?," Build. Environ., vol. 191, p. 107602, Mar. 2021, doi: 10.1016/j.buildenv.2021.107602. [36] S. Fantucci, S. Garbaccio, A. Lorenzati, and M. Perino, "Thermo-economic analysis of building energy retrofits using VIP - Vacuum Insulation Panels," Energy Build., vol. 196, pp. 269–279, Aug. 2019, doi: 10.1016/j.enbuild.2019.05.019. [37] "Rules on efficient use of energy in buildings," pisrs. Accessed: Dec. 20, 2023. [Online]. Available: http://www.pisrs.si/Pis.web/pregledPredpisa?id=PRAV14331 [38] “Productions - Buzon.” Accessed: Dec. 20, 2023. [Online]. Available: https://www.buzonworld.com/realisations/ [39] S. Resalati, T. Okoroafor, P. Henshall, N. Simões, M. Gonçalves, and M. Alam, "Comparative life cycle assessment of different vacuum insulation panel core materials using a cradle to gate approach," Build. Environ., vol. 188, p. 107501, Jan. 2021, doi: 10.1016/j.buildenv.2020.107501. [40] "ECO Platform." Accessed: Apr. 03, 2019. [Online]. Available: https://www.eco-platform.org/ World Sustainable Built Environment 2024 IOP Conf. Series: Earth and Environmental Science 1363 (2024) 012067 IOP Publishing doi:10.1088/1755-1315/1363/1/012067 17 [41] One Click LCA, "World’s fastest Building Life Cycle Assessment software - One Click LCA,” One Click LCA® software. Accessed: Mar. 12, 2021. [Online]. Available: https://www.oneclicklca.com/ [42] “DesignBuilder Software Ltd - Home.” Accessed: Dec. 20, 2023. [Online]. Available: https://designbuilder.co.uk/ [43] “EnergyPlus | EnergyPlus.” Accessed: May 17, 2020. [Online]. Available: https://energyplus.net/ [44] R. Kunič, “Carbon footprint of thermal insulation materials in building envelopes,” Energy Effic., vol. 10, no. 6, pp. 1511–1528, Dec. 2017, doi: 10.1007/s12053-017-9536-1. Appendix A Table A1: Heating energy for buildings A and B. Solution 2 exerts approximately 3.5 higher terrace U-value than other solutions. Building A Building B Heating demand [kWh] delivered (COP 0.85) [kWh] demand [kWh] delivered (COP 0.85) [kWh] SOLUTION 2 2571.95 3025.82 9099.66 10705.48 Base case + SOLUTION 3-5 2194.96 2582.31 8770.97 10318.79