Buildings primarily contribute to climate change impacts through:
- the energy they use when the building is occupied
- the greenhouse gas emissions from the extraction, processing, transport and installation of building materials and their maintenance and eventual disposal or recycling
- urban and landscape design and planning.
The New Zealand Productivity Commission report Low-emissions economy notes that, while New Zealand’s absolute contribution to global emissions is small, our per-person gross emissions are one of the highest among developed countries.
Greenhouse gas emissions from our buildings arise from manufacture and transport of the materials used in construction, use of fossil fuels for heating and cooking and use of electricity for space heating and cooling, water heating, lighting and plug loads, part of which is supplied using fossil fuels.
A 2016 Royal Society report Transition to a low-carbon economy for New Zealand found that greenhouse gas emissions can be reduced in New Zealand residential and commercial buildings through better energy management and improved minimum performance standards for appliances.
Emissions reductions can also result from:
- improving insulation levels
- retrofitting existing building stock
- integrating renewable energy systems
- supporting innovative green building designs.
The aim and the problems
The aim is to build net-zero carbon buildings - buildings whose greenhouse gas emissions over their life cycle are within New Zealand’s commitments to a net-zero carbon economy.
There are currently few economic incentives to encourage action, and the New Zealand Building Code does not require buildings to be net-zero carbon. Even if the demand were there, the industry has significant gaps in skills and knowledge required to deliver net-zero carbon buildings.