Housing stock strategies for meeting NZ’s 2050 carbon target

New Zealand has committed to net zero carbon emissions by 2050. The Building and Construction Sector currently accounts for around 20% of our carbon emissions through the energy and materials used in buildings. This research responds to MBIE’s Building for Climate Change (BfCC) Programme (released August 2020), which delivers central government’s Emissions Reduction Plan. It does this by addressing both operational (i.e. ongoing) and embodied (i.e. in materials) carbon in buildings. This BRANZ research shows MBIE the implications of several decarbonising strategies associated with a building subset - residential housing - with the goal of meeting NZ’s 2050 climate targets. Using an estimate of the current and projected residential building stock to 2050, BRANZ and Massey University researchers found that approximately two-thirds of emissions are due to existing houses and about one-third due to houses yet to be built. Whilst existing housing provides the largest contribution, opportunities to reduce carbon emissions are more limited in comparison with new houses. This proposal seeks to use BRANZ’s existing stock model and residential building carbon footprint data to test different possible decarbonising strategies that could be implemented in existing houses, or new houses, or both. The research seeks to understand and estimate the potential greenhouse gas savings associated with implementation of these strategies relative to ?business as usual? emissions. The evaluation will consider potential ?embodied carbon? costs as well as ?operational carbon? benefits. In brief, we need to understand what combination of strategies (in new and existing dwellings) provide the greatest potential for net carbon savings and relate this to New Zealand’s net zero carbon commitment.