Upgrading New Zealand’s existing office buildings – An assessment of life cycle impacts and its influence on 2050 climate change mitigation target

The aim of this study was to estimate potential environmental impacts associated with adopting energy efficiency refurbishments on the existing office building stock in New Zealand. Additionally, a second objective was to identify the potential contribution of the office building stock in relation to New Zealand’s 2050 climate change mitigation target. For this purpose, the study used Life Cycle Assessment in conjunction with stock aggregation modelling. The impacts of the building stock were calculated for non- refurbished building stock; refurbished building stock; refurbished building stock adopting resource and waste management measures and; refurbished building stock installed with photovoltaic panels. The results highlight the achievability of New Zealand’s 2050 target in the office-building sector with a potential to reduce 40–98 % CO2 eq. emissions. Use of photovoltaic substantially increases the resource demand of refurbished buildings. Prioritizing the refurbishment of the building stock by adopting efficient resource use and waste management measures can contribute to reductions in greenhouse gas emissions without increasing environmental pressures from resource demand. Moreover, prioritizing refurbishment activities in major cities and/or in large buildings can be an effective measure to achieve 2050 target but not at the cost of increasing other environmental impacts.