Where We Build What We Build
As natural hazards intensify because of climate change, living expenses like energy, mortgages and insurance will get more expensive for climate vulnerable homes – that is, homes that are in high-risk areas and have not been built to mitigate those risks.
The Where We Build What We Build project aims to encourage building or retrofitting of homes that are climate-ready, by demonstrating that the benefits of doing so outweigh the costs.
One of the goals of the Adelaide Hills and Fleurieu Peninsula region is to remain liveable, affordable and resilient in the changing climate, by better managing climate risks.
To help achieve this, the project explored:
- Where We Build – the exposure of the region's existing housing to flood, heat and bushfire risks
- What We Build – the sensitivity of the region's existing housing to those risks
- Climate-Ready Home – the ideal specification for a climate-ready home in the region
- Economic Analysis – the costs and benefits of building or retrofitting to climate-ready specifications, compared with existing housing stock and standards.
The economic benefits of climate-ready homes outweigh the costs for both new builds and retrofits. Meanwhile, vulnerable housing leads to higher living costs and lower community resilience.
Over a 50-year period, the net present value of immediately retrofitting the region's housing stock to a climate-ready standard is estimated at over $72 million.
The building stock in the region varies significantly in terms of its resilience to natural hazards. Overall, 70% of the 2,956 homes in regional climate hazard hotspots had a resilience rating of less than 3 out of 5.
There is already information available to know how to build or retrofit climate-ready homes, but current baseline building compliance needs to be further improved to provide climate resilience.
With insurance premiums expected to quadruple over the next 20 years, the changing cost of insurance will influence how we build and retrofit homes. A climate-ready home can attract a premium 8.5% lower than a contemporary home, and up to 47% lower than a Victorian home. Agreed climate-ready standards should be developed with the insurance industry, enabling them to provide preferential insurance products.
Poor quality natural hazard data impacts insurance premiums. South Australians pay an estimated 18% too much for home insurance premiums because of data uncertainties. This finding supports the need for a centrally coordinated, jointly resourced hazard mapping framework in South Australia to overcome these knowledge gaps and encourage climate resilient decision-making.
The insurance industry uses maps on natural hazard risk, and information on construction materials and design, to judge the probability and size of an insurance claim arising from climate hazards. This information is used to set insurance premiums.
It is expected that insurance premiums will rise as hazard exposure increases under climate change. In climate exposed areas, the increase can be significant enough to help justify greater use of climate resilient materials in new or retrofitted homes.
Maps generated from the project can be accessed at http://edge.endevgeo.com/ (project: wwbwwb).
Key projects outcomes can be found in the following fact sheets:
- Project overview
- Regional climate hazard mapping
- Regional housing archetypes
- How to build climate ready homes
- Climate resilient materials
- Guide for planners
More detailed information on the methods and results are contained in the final project report.
The project is an initiative of Resilient Hills & Coasts, delivered by Edge Environment. It was jointly funded by the Commonwealth and South Australian Governments under the South Australian Disaster Resilience Grant Program, and the Insurance Council of Australia. Partner Councils were the Adelaide Hills Council, Alexandrina Council, Mount Barker District Council, City of Victor Harbor and District Council of Yankalilla. The views and findings of this project are expressed independently and do not necessarily represent the views of the funding bodies.