Passive Design

Designing for climate change

Buildings should be designed to reduce greenhouse gas emissions over their usable lives, and cope with climate change impacts.

On this page:

• designing to cope with climate change
• reducing greenhouse gas emissions

Buildings designed today will have to be able to Climate change will affect house design in two principal ways. 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.

New Zealand homes have an average lifespan of over 80 years, and in some cases, up to 150 years. Homes will need to be designed to cope with changes in climate conditions over the expected lifetime of the building. This may include higher temperatures, different wind and rainfall patterns, and potentially increase incidence of hazards such as floods and storms.

Buildings are significant emitters of greenhouse gases, firstly in the materials used and the construction process, and – more significantly – 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.

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.

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
• specifying energy-efficient lighting, heating, water heating and appliances
• incorporating rainwater collection and storage
• installing water-use reduction fittings.