Completed by global engineering consulting firm WSP with funds from Local Government NSW, the Future Proofing Residential Development to Climate Change report was released earlier in 2021.
The authors aimed to test modern building standards against the impending effects of climate change to see how they stacked up across the categories of building thermal performance, energy consumption, greenhouse gas emissions and water demand.
They modelled the performance of compliant structures against future climate projections for Eastern Sydney, including the Randwick, Woollahra and Waverley council regions.
They said that with elevating temperatures, demand for thermal cooling and water usage would go up, rendering the majority of building types non-compliant with present BASIX requirements by as soon as 2030.
Former BASIX policy developer David Holden, now director of urban sustainability software firm Kinesis, informed The Fifth Estate that the present system was set for a transformation.
BASIX was created to address resource consumption and emissions of new residences more than 15 years ago, Holden said.
The question, in his mind, was will these houses be liveable in the future? And will our infrastructure meet the challenge?
While the study was inspired by modelling for Sydney’s Eastern beaches, the authors say that the conclusions might be applicable to other jurisdictions undergoing similar shifts in temperature and rainfall.
This stands among the most complete and targeted studies in exploring the place of BASIX against the more extreme results of climate change.
The Randwick City Council has indicated that the report’s recommendations would be presented at a June meeting, after which they will come up for a vote.
With elevating temperatures looming in the future, the study predicted that summertime energy demand for mechanical cooling like airconditioning would go up substantially.
The study’s modelling indicates that, in 2030, cooling loads would rise by 70 per cent on average above contemporary baseline demand while by 2070 they would rise by 308 per cent on average above contemporary baseline demands.
The buildings most afflicted by hot temperatures would be the attached, detached and low-rise dwellings, while the least affected would be high-rise buildings which would benefit from possessing a higher ratio of shared walls, floors and ceilings and access to improved natural ventilation.
These results demonstrate it is feasible the homes approved for building now will be ill-suited for residence by 2070, without elevated levels of mechanical cooling to keep comfortable, secure and liveable conditions, the report stated.
The concepts of climate responsive design would specify that, in response to the report, residential building designs should be accounting for hot climate conditions to deal with cooling comfort requirements.
Energy consumption was flat by 2030, with calls for cooling offset by lesser demand for heating which was predicted to decrease. Yet by 2070 major boosts in cooling demand were demonstrated to cause four of the five building types to fail BASIX Energy qualifications.
In regards to water usage all building types failed to pass the BASIX Water target when modelled in the 2030 climate scenario of reduced rainfall.
Detached homes received the lowest rating due to factors that include more extensive landscaping requirements while high-rise buildings garnered one point short of passing the requirements.
The report indicates that 2070 is expected to be less dry than 2030, but drier than today’s climate, indicating that all building types except high-rise fell short of attaining the BASIX Water target for 2070.
The key report findings are that NSW will have to take into account significantly higher demand for mechanical cooling such as airconditioning, both from more intense demand and greenhouse gas emissions perspectives.
In regards to thermal performance, the report recommended updating the climate files utilised in the NatHERS software to guarantee dwellings are designed to endure future conditions and exploring design modifications for various building varieties to guide the Thermal Comfort policy setting in BASIX under future climate scenarios.
As NSW has endured during prolonged drought over the past 20 years, with a warming climate, water availability can become more and more unpredictable.
The report stated that water demand is expected to rise as the climate warms. Also, projections for longer periods of lower rainfall alternative water supplies may work toward the BASIX Water targets, advising treated storm water and recycled water reticulation as two feasible resolutions.
BASIX might be updated to consider projected heightened demand and drier climatic conditions and that additional testing of differing building types be conducted to guarantee future compliance to BASIX Water targets.
The report also advised that BASIX be reviewed and adapted every three years in accordance with National Construction Code (NCC) updates and that utilities are needed to monitor the energy and/or water consumption of BASIX dwellings to enhance system data.
Source: The Fifth Estate