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Purpose: In recent years, the building sector has highlighted the importance of operational energy and efficient resource management in order to reduce the environmental impacts of buildings. However, differences in building-specific properties (building location, size, construction material, etc.) pose a major challenge in development of generic policy on buildings. The aim of this study was to investigate the relationship between energy and resource management policies, and building-specific characteristics on environmental impacts of refurbished office buildings in New Zealand. Methods: Life Cycle Assessment (LCA) was performed for 17 office buildings operating under seven representative climatic conditions found in New Zealand. Each building was assessed under four policy scenarios: (i) business-as-usual, (ii) use of on-site photovoltaic (PV) panels, (iii) electricity supply from a renewable energy grid, and (iv) best practice construction activities adopted at site. The influence of 15 building-specific characteristics in combination with each scenario was evaluated. The study adopted regression analysis, more specifically Kruskal-Wallis and General Additive Modeling (GAM), to support interpretation of the LCA results. Results and discussion: All the chosen policies can significantly contribute to climate change mitigation as compared to business-as-usual. However, the Kruskal-Wallis results highlight policies on increasing renewable energy sources supplying national grid electricity can substantially reduce the impacts across most environmental impact categories. Better construction practices should be prioritized over PV installation as use of on-site PV significantly increases the environmental impacts related to use of resources. The GAM results show on-site PV could be installed in low-rise buildings in regions with long sunshine hours. The results also show the strong influence of façade elements and technical equipment in determining the environmental performance of small and large buildings, respectively. In large multi-storied buildings, efficient HVAC and smaller window area are beneficial features, while in small buildings the choice of façade materials with low embodied impacts should be prioritized. Conclusions: In general, the study highlighted the importance of policies on increasing renewable energy supply from national grid electricity to substantially reduce most of the impacts related to buildings. In addition, the study also highlighted the importance of better construction practices and building-specific characteristics to reduce the impacts related to resource use. These findings can support policy makers to prioritize strategies to improve the environmental performance of existing buildings in New Zealand and in regions with similar building construction and climate. [ABSTRACT FROM AUTHOR]

Large scale building refurbishments are likely to become more common in New Zealand's building sector, and therefore it is relevant to assess the environmental impacts associated with these activities. The aim of this study was to investigate the environmental impacts arising from the increase in demand for building refurbishments in New Zealand using consequential Life Cycle Assessment (LCA). The study focused on the identification of resource constraints and marginal suppliers of construction materials using market information specific to New Zealand. Building refurbishment strategies related to waste minimization at construction sites and use of recycled materials at production sites were compared. According to the results, increasing the rates of construction waste recovery and re-use at site can reduce the overall environmental impact of a building refurbishment by 15–25% compared to use of construction materials with recycled content which only reduces the environmental impacts by approximately 5%. The net impact results were sensitive to the quality of recyclable material, location of the marginal supplier and marginal energy source. The study recommends stakeholders involved during early building design to focus on material sourcing and quality; and practical solutions to increase material recoverability at site e.g. planning for efficient on-site management for waste disaggregation, recovery and re-use. [ABSTRACT FROM AUTHOR]