NatHERS mandatory accreditation makes sense

Since I left Sustainability Victoria 16 years ago, I’ve been a “broken record” about the critical importance of NatHERS assessor accreditation. As a public servant who helped establish NatHERS, it was clear then. Its importance is only greater now, particularly with the introduction of new energy efficiency regulations in NCC 2022, scheduled for implementation in 2023.

It’s not as easy as it looks

Energy Ratings suffer from a perception problem. Energy Rating is typically a lower-cost item in the range of regulatory assessments you need to get a building permit. Cheaper than a soil test or structural calculations. Maybe a few hundred dollars or less. Builders can send the plans to an assessor and get an answer in a couple of days. Sometimes, same day. So it couldn’t be that hard?

To answer that question, consider this:

Every assessor has to know about the full range of available energy-efficient products, how they work, what difference they make, when they can be used and when they can’t, and how expensive they are.

For a rating to be valid, it must be assessed using the NatHERS Technical Notes (30 pages). There have been five versions since 2013 that change how you can enter data into rating tools. And it can’t cover every circumstance in 30 pages, so there is also an Assessor Handbook (125 pages). NatHERS software suppliers and accrediting organisations have a helpline and FAQ resources to cover what these resources don’t.

NatHERS software tools are regularly updated. Having as many as 6 versions on your computer at any time is not uncommon. Each version has a slightly different data entry method, a different software manual (100 pages plus), an applicable Tech Note, and an applicable NCC version. Each software version may deliver a different rating for the same house. You need all these versions to handle projects where the design may have been substantially complete before the current version of the NCC and to answer queries about historical ratings.

Designers, builders and homeowners all have competing desires for the house that may make it much harder to achieve compliance. They don’t want to change a design that may have taken months to develop. They may want to have the biggest windows possible to capture that special view to the west regardless of how hot the house may be in summer. The builders preferred product suppliers may not have a product with the performance needed. This means that the most straightforward way to achieve compliance can be off the table. Achieving compliance without “compromising” the design can be a difficult juggling act.

And then, there are the windows—the most critical part of achieving compliance. There are over 50,000 windows in the Window Energy Rating Scheme database. But only about 15,000 of them have been available in NatHERS software tools. And some windows don’t have a WERS rating. The rules for how assessors handle this have changed at least twice in the last few years.

The construction of the house should achieve the performance specified in the rating. So, the building permit documentation must contain all the data that affects the energy. The assessor must check every plan, elevation, section, construction detail, site plan and specification page to ensure it is consistent with the rating assumptions.

Assessors face a lot of pressure to make the building comply. The industry wants to get the rating over and done without changing anything. They understandably don’t want to lose time updating documentation and don’t want to add costs upgrading specifications the client may not be able to afford. And making different but wrong data entry assumptions here and there can save construction costs and deliver rating compliance sooner rather than later. The overwhelming majority of assessors play a straight bat, but the temptation to hook one over square leg is ever-present.

The fact that NatHERS assessors make it look easy and don’t charge too much for a rating is a credit to assessors. But like a duck gliding over a pond, a lot is going on below the water line that the industry doesn’t see. And often, assessors have to do this swimming against a tide of expectations.

NCC 2022 just made the job harder

I’m not against the changes. I helped develop them. I believe they are an essential strategy to help Australians meet the challenge of climate change. But I’m also keenly aware that new regulations will require a change to industry practices if the cost of the regulations is to be contained.

Achieving 7-stars will require more collaboration between assessors and designers earlier in the design process. Houses will need to be more carefully tuned to their climate and site conditions, particularly on heavily overshadowed sites. If you want big windows, they’ll need to be in the best orientation. And subdivision designers will need a far more sophisticated design approach to ensure houses can achieve good window orientation to living areas while maximising lot yield to contain housing costs. I’m confident assessors and designers will get on top of the issues, but the first years of implementation will be challenging.

The new regulations also include the efficiency of heating, cooling, hot water and pools, as well as the contribution of rooftop solar. Having been through the process myself, I know it isn’t too hard once you get used to it, but getting the Whole of Home part of the new regulations running smoothly will take a while.

Assessors need support, and consumers need protection

The cost and tragedy of the global flammable cladding issue demonstrates that careful enforcement of regulation is essential. Poor compliance with energy efficiency regulations doesn’t put the life of the occupants of a home in immediate danger, like flammable cladding. However, you only need to look at the increased frequency of fires and floods worldwide to understand that the successful implementation of energy-efficient building regulations contributes to human safety.

In 2013, when NatHERS Tech Notes were first introduced, a benchmark study of accredited assessor accuracy was conducted. Of the 344 assessors that participated, only around one-third achieved a rating within 0.25 stars of the correct rating. Most of the errors overestimated the energy efficiency of the dwellings. The study recommended changes to software, scheme management, assessor support and auditing and Continuing Professional Development. Most of the recommendations were implemented and will have contributed to higher accuracy in the assessor industry. But, this is only true for those assessors who work under the accreditation framework.

Accredited assessors must undertake a minimum amount of CPD every year to keep them up to date with industry changes. They are subject to auditing and must demonstrate that they have learned from their mistakes if they fail. Accreditation brings new assessors into an industry community where they can learn from industry leaders. And most importantly, accredited assessors must have Professional Indemnity (PI) Insurance. PI insurance protects consumers when the regulatory system has failed. And this protects the energy bill savings and Greenhouse Gas emissions reductions the regulations are intended to achieve.

The NatHERS assessor industry is a relatively new field, having existed for less than 20 years. Being an assessor is a complex job that requires the assessor to stay abreast of changes in a rapidly developing industry. The industry is delivering lower energy bills for consumers in a time of increasing energy prices. It delivers lower GHG emissions in a world where climate change’s confronting consequences make headlines daily. And we know that without accreditation, the ability of assessors to deliver good outcomes is far from certain. It is about time all state and territory governments required all NatHERS assessors to be accredited.

Tony has worked as a lecturer in Thermal Performance at Melbourne University’s Department of Architecture, as an Architect for the Ministry of Housing, Principle Project Manager, Buildings at Sustainability Victoria, Senior research Fellow at RMIT Centre for Design and has managed his own business as a Sustainable Building Specialist for 8 years. Tony has worked as a lecturer in Thermal Performance at Melbourne University’s Department of Architecture, as an Architect for the Ministry of Housing, Principle Project Manager, Buildings at Sustainability Victoria, Senior research Fellow at RMIT Centre for Design and has managed his own business as a Sustainable Building Specialist for 8 years.

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