FEATURE: NSW has historically trod its own path to regulate the sustainability standards of its homes. And while BASIX, the NSW-specific planning controls that override National Construction Code requirements on emissions and other sustainability criteria, started life as a market-leading tool, some say it’s now losing its edge and stymying progress towards next generation technologies such as heat pumps. The Fifth Estate set out to investigate these claims and found that while the tool has robust foundations, most agree BASIX is in need of some love, including NSW Minister for Planning and Public Spaces Rob Stokes.


When the state government first created BASIX (the building sustainability index) back in 2004 to set minimum targets on emissions and water for new homes and major renovations, it set the bar high.

BASIX picked up a swag of awards in the early years, including the Gold in the Environment category at the Premier’s Public Sector Awards in 2004, and is considered largely responsible for water tanks becoming a common sight in NSW backyards.

Fast forward to today and the BASIX tool is failing to keep up with the rapid innovations to decarbonise and future proof NSW’s housing stock. It’s not alone: criticisms have also been levelled at the star rating system used by every other state and territory in the country, the Nationwide House Energy Rating Scheme (NatHERS).

Minister Rob Stokes

So it’s promising to hear that NSW Minister for Planning and Public Spaces Rob Stokes is on the job. Speaking at an event at Sydney Olympic Park on Wednesday, he told The Fifth Estate that his department was working on much-needed updates, with the first look at proposed changes expected by the end of the year.

A priority for Stokes is ensuring the standard is flexible enough to reward architects pushing the envelope and going above and beyond the minimum sustainability requirements.

Stokes also signalled a move towards greater alignment between BASIX and NatHERS so that there’s a consistent minimum sustainability standard across all states and territories.

BASIX has good bones

One the creators of BASIX, Kinesis Australia director Bruce Taper, told The Fifth Estate that one advantage of the standard is that it’s a comprehensive “whole-of-house” measurement.

It sets performance-based targets for both water use and greenhouse gas generation based on 2004 estimates (when it was created). These performance targets were based on data analysis of energy and water use at the postcode level.

BASIX considers the performance of the whole house – including appliances – and not just the building shell. By contrast, NatHERS is solely concerned with the thermal envelope, that is, the amount of heating and cooling required to keep the indoor air temperature comfortable.

Taper says this discrepancy between what the two tools actually measure helps refute one of the most enduring criticsm of BASIX in recent times – that it effectively asks for around a 5.5 star NatHERS rating equivalent to pass muster, when the national minimum everywhere else is 6 stars as per the National Construction Code.

City of Sydney environmental advisor David Eckstein, who was also involved with BASIX in the early years, says a lot plays into the reliability of BASIX energy estimates, including
“thermal performance modelling tools providing a reasonable estimate of real-world energy loads, the accuracy of modelling by the thermal performance assessor, and compliance with design commitments at building construction stage.”

NatHERS is now following BASIX’s lead and moving towards “whole of house” assessments. It also mimicked the NSW tool on the heating/cooling split that accounts for differences in energy use in summer and winter. Before this split, many homes performed poorly in the heat thanks to design flaws such as dark-coloured roofs and no eaves.

The Fifth Estate also understands that BASIX also has advantages over NatHERS for assessing apartments – representing a growing proportion of new housing built in NSW – such as accounting for energy use in common areas.

Bruce Taper, Kinesis Australia

Has BASIX lost its edge?

BASIX may have set a cracking pace on improving the sustainability performance of NSW’s housing stock but both Eckstein and Taper believe it needs updating.

From the outside, it doesn’t look like the tool has been updated regularly or thoroughly enough. According to the website, one change in the greenhouse (BASIX Energy) target and a round of tightening of heating/cooling “caps” in 2017 are the only significant updates to the scheme in 15 years.

Taper agrees the updates to BASIX have been sporadic, and these changes could have been more ambitious.

“It could do with a bit of love. A lot of love has gone into the National Construction Code, there’s been a huge investment in that. BASIX has had only a small fraction [of work done on it] by comparison.”

Eckstein says the tool likely needs a refresh in how it divvies up weightings to different technology options, energy end-use calculation and emissions factors.

“While greenhouse gas emissions factors have occasionally been updated in BASIX, there has been no formal review, with industry engagement, of the scoring attributed to different energy using equipment and technologies.

“Some equipment and technology efficiencies have evolved significantly over the last decade. The calculation engine behind an online planning tool like BASIX should be regularly reviewed to reflect best available performance information.”

The BASIX standard is irrefutably out-of-date on some technologies. BASIX certifier Ian Fry, founder and director of Fry Energy Wise, believes BASIX needs updating so the requirements are more relevant to today’s standards and products.

Ian Fry, Fry Energy Wise

For example, the standard calls for dedicated fittings for compact fluorescent bulbs and LED lighting when they are now the only options available to buy. He says requirements like this are confusing for the certifier, the builder and the homeowner.

Eckstein is also disappointed with the state of the online platform. While the “e-planning” format was cutting edge when BASIX was first implemented back in 2004, it’s barely been touched since. This is made more confusing given BASIX fees were introduced 10 years ago.

“The introduction of BASIX Certificate fees in 2010 is reason enough for industry and local government to expect a significant reinvestment in the BASIX web tool,” he told The Fifth Estate.

“The policy architecture is generally sound, but the once cutting-edge web-delivery aspects are in need of update to align with user expectations of digital tools, especially in the case of the apartment sector.

“Given the work that the department has to do anyway in the lead-up to the 2022 introduction of a national approach to whole of home energy assessment, the time is absolutely right for proper reinvestment in the scheme.”

Is BASIX nudging home builders towards gas heating and cooking?

Another growing concern is that the tool is pushing home builders towards natural gas systems for heating and cooking rather than electric alternatives, such as heat pumps and induction cooking.

According to Glenn Day, the director national sales & public affairs of energy technology manufacturer  , existing regulatory schemes throughout Australia, including both BASIX and NatHERS 6 start minimum requirements in other states, makes it “very difficult” to install a heat pump in a new home.

Speaking at The Fifth Estate’s Flick the Switch event on 5 August, Day also said that different ratings and standards in each state for heat pumps make Australia a risky market for manufacturers and investors.

In fairness, BASIX bases its emissions intensity profile of both gas and electrical appliances on the annually updated National Greenhouse Accounts Factors. The reality is that gas remains a lower emission fuel in many states and territories where the grid

Glenn Day, STIEBEL ELTRON

still relies heavily on fossil fuels, such as NSW, and if an electric appliance isn’t powered by rooftop solar or purchasing renewable energy from energy providers, there’s a good chance the gas alternative will be lower in emissions.

Ian Fry has provided BASIX certification for some of NSW’s largest home builders and designers and says getting heat pumps and other electric systems over the line with BASIX is “almost impossible” without adding a dedicated rooftop solar system.

While this might sound reasonable, Fry says builders have become wary of including the solar systems in their contracts due to past experiences with substandard installers leaving them with ongoing maintenance issues.

“The upfront cost of solar is also a hurdle for financially strapped clients,” he adds.

The tool should reward green energy, solar communities, better thermal performance, ceiling fans….

While Fry says BASIX is overall a “good sustainability tool”, he believes it should be more flexible if we want to meet our ambitions of becoming a low emission economy.

He’d like to see the tool rewarding commitments to buying green energy, solar communities, adding to the thermal performance of the home through increased insulation and improved windows, the use of ceiling fans in a software assessment, and the siting of the home so the orientation makes better use of the sun.

“The end goal is to work towards a low emission economy, I think we should be considering all options for the home builder and the homeowner to make it easier to meet that goal.

“If the path is made easier by allowing more options, I have no doubt we will see even more energy efficient and sustainable homes being built in NSW.”

He would also like to see the performance of the home and the use of the home (Thermal Comfort and Energy) considered as one, especially for projects where dedicated rooftop solar is not viable.

We’re in danger of locking in housing stock that’s not future proof

Although the emission intensity of gas might be lower than electricity at the moment, the grid will decarbonise – and sooner rather than later. AEMO expects Australia’s grid to experience the world’s fastest transition to low carbon energy sources, with a business-as-usual scenario expected to deliver a 74 per cent renewables share by 2040 and a 94.2 per cent penetration if we try a bit harder.

With the energy regulator making those kinds of predictions, you’d expect the compliance tools designed to limit the emissions profile of Australian homes to be accounting for our energy future.

None of the tools are doing enough

RMIT lecturer Dr Trivess Moore says neither BASIX nor NatHERS are doing enough to accommodate future climate data. The danger of compliance tools that are reactive rather than proactive in nature, he says, is that they risk locking in housing that’s suitable for today but ill-equipped for the environmental challenges of the future.

The end result could be people stuck with homes reliant on gas heating and cooking that will most likely need to be retrofitted to electric alternatives run on 100 per cent renewables.

Appliances can be easily swapped out, building fabric cannot

Another source, who prefers to remain unnamed, questioned the scheme’s generous treatment of energy efficient appliances over permanent fixtures, such as the building envelope, even though a fridge and other equipment can be later replaced with low performing kit by the occupants.

While a spokesperson from the Department of Planning, Industry and Environment admitted that there’s a chance that this will happen, the spokesperson said, “this will make very little difference to predicted greenhouse savings as energy ratings continue to improve”.

Updates end up in the too hard basket

While it’s clear BASIX needs an overhaul, it’s a legal document so “changes cannot be made overnight”, Ian Fry says.

The scheme is updated according to a schedule every four years with next one set for 2022 alongside the next National Construction Code update.

For Fry, that is “far too long a wait”, so it’s good news the NSW planning minister Rob Stokes has signalled earlier updates.

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  1. Its been a really interesting process to get my new house plans to pass Basix.
    I live in a very hot climate for 9 months of the year (and this is expanding) and the other 3 months is lucky to get to 0.C at night. But yet, I have designed a big esky to protect us and to use minimal energy to control the internal environment. The external products and structure I have chosen is to try to have the perfect balance of insulation/cost/performance. I have had to compromise with building products to pass Basix, that in turn has raised the cost of insulation and construction to maintain desired performance. It amazes me that I’m going for a carbon negative house with great technology and this all this has little to no effect on the Basix. It’s really keeping the Australian building science and the industry held back to stay sub standard to other developed countries.

  2. This is an example of where the private sector can do better than government which is contrary to some popular opinion. BASIX has suffered years of neglect, while GreenStar has continued to evolve and recently released a version for homes. We need to recognise that sometimes it can be better for these things to be independent of government with its short term focus on political cycles.
    Then again, look at the success of NABERS, also managed by NSW government and going so well it is being exported globally! Is it time for BASIX to be managed by the NABERS team?

  3. For me there is serious disconnect between the NCC/NatHERS/BASIX and a survivable future for our kids/grandkids. To meet the Paris aspiration of less than 1.5DegC of climate change we really need to be well on the way to carbon neutral by 2030. That means that ALL of our new buildings NEED to be carbon neutral NOW AND because the stock only gets replaced at 1-2% per year, we NEED a massive push for carbon neutral in the existing stock at the same time. Anything less is psychopathic toward future generations, but most folk seem to think that what I’ve written here is naive and extreme. When did not sending our species extinct become extreme?