Passive Design

Designing the building and the spaces within it to benefit from natural light, ventilation and even temperatures.

Designing for climate change

Buildings should be designed and operated in such a way that they are responsible for fewer greenhouse gas emissions. They also need to be designed to cope with the impacts of climate change in coming decades.

On this page:

  • designing to cope with climate change
  • reducing greenhouse gas emissions
  • BRANZ resources for climate-friendly designs

New Zealand houses have an average serviceable life of over 80 years, and some have lasted over 130 years. Buildings constructed today must therefore be able to deal with climate changes forecast for the long term. Houses will need to be designed to:

  • respond appropriately to a changing climate with higher temperatures, different wind and rainfall patterns and potentially increased incidence of hazards such as flooding and storms
  • minimise emissions of carbon dioxide and other greenhouse gases over their usable lives. Greenhouse gases contribute to climate change.

Buildings emit greenhouse gases in the materials and processes used in their construction, and in the energy and other resources used over the life of the building for heating, cooking and washing. Good passive design can help to minimise energy use while maintaining a comfortable and healthy environment, so reducing greenhouse gas emissions. Installing high levels of thermal insulation and reducing volumes of waste are key measures.

Designing to cope with climate change

The impact of climate change will vary from region to region. Designers will need to consider:

  • incorporating passive solar design features to reduce the need for heating in winter and air-conditioning in summer
  • designing buildings with more shading in response to increased solar radiation
  • increasing structural design to deal with increased wind loading
  • designing buildings to make more use of natural ventilation
  • designing the roof, roof drainage and stormwater run-off to cope with higher and more intense rainfall
  • incorporating water-saving features in homes to reduce pressure on urban water supplies (see Water)
  • potential flood risk in low-lying areas
  • limiting building in flood-prone areas or coastal regions that are likely to experience increased erosion in the future.

Reducing greenhouse gas emissions

Carbon dioxide and other greenhouse gases are emitted through the process of building construction and use including during:

  • material extraction, manufacture, processing and transportation
  • construction
  • occupation – a typical New Zealand home emits more than 3,000 kg of carbon dioxide every year
  • demolition – emissions from landfills are estimated to make up 4% of New Zealand’s total emissions.

Of these, the most significant is carbon dioxide emission through energy use. Limiting domestic greenhouse gas emissions is essential to reduce the impact on the environment as well as for economical reasons.

Greenhouse gas emissions can be reduced in a number of ways including:

  • selecting a site that can take advantage of passive solar design
  • designing an appropriately sized home i.e. if too large, materials and energy will be wasted
  • incorporating passive design features such as orientation, insulation, and thermal mass to provide a comfortable internal environment while minimising energy use
  • selecting materials with fewer emissions over their life cycle
  • designing in a way that results in less material waste on site (for example by working to the standard sizes that materials come in to reduce offcuts)
  • specifying energy-efficient lighting, heating, water heating and appliances
  • incorporating rainwater collection and storage
  • installing water-use reduction fittings.

BRANZ resources for climate-friendly designs

BRANZ has developed a suite of online carbon tools that can help in the design of low-carbon buildings. There are three carbon footprinting tools and two life cycle assessment tools:

  • CO2NSTRUCT is a database of embodied carbon and energy figures for building materials and products.
  • CO2RE covers greenhouse gas emissions for residential wall, floor and roof constructions (expressed as per m2 of the building element). It allows evaluation based on construction R-value and whole-of-life embodied carbon.
  • CO2MPARE is a database of calculated greenhouse gas emissions for a set of reference residential and office buildings. It also contains carbon budgets for those buildings. It can be used for benchmarking and target setting.
  • LCAQuick calculates environmental impacts of any building designs, with a focus on residential and office typologies.
  • LCAPlay is a concept-level exploratory LCA tool for commercial buildings.

You can find more information in the Environment and zero-carbon research section of the BRANZ website.


Updated: 08 February 2022