NatHERS assessments are a complicated thing. With this post we’d like to explain the different pieces that make up NatHERS, so you can understand how they affect your energy assessment. NatHERS needs all it’s parts to work together, otherwise it’ll work as well as a car with only three wheels – your energy assessment report could become a rolling disaster!
What is NatHERS?
- The word itself is an acronym that stands for the “Nationwide House Energy Rating Scheme”
- It’s a system that gives houses Star Ratings (from 0 to 10 Stars) for energy efficiency
- It’s overseen by the Federal Department of the Environment and Energy, on behalf of all Australian States and Territories
- It’s referenced in the National Construction Code, which is often abbreviated to the NCC
- If a dwelling has a Thermal Calculation method of energy assessment, then it must also have a Star Rating
What parts make up NatHERS?
NatHERS can be broken down into four main parts. If one component isn’t running effectively, then (using the car analogy) the wheel is not “on” the car. It may even have an accident and someone could suffer damages or financial losses. Any business or certifier worth their salt should be checking to make sure all four parts are functioning correctly.
The first part is using approved NatHERS Software
All valid assessments must be calculated using accredited software that correctly implements the CSIRO-developed Chenath calculation engine. There are three Accredited software packages available: AccuRate (which is also the reference benchmark implementation), BERS Pro, and FirstRate5. New versions are released regularly, and these are checked to make sure their results align with the benchmark software – only the current approved version should be used. However, similar to how just owning a car doesn’t mean you can drive it, there’s much more to it than just using the right software to produce a certificate!
The second part is ensuring trained & qualified Assessors are accurately entering data into the Software
Of course, there needs to be standard procedures to make sure Assessors know how to use the software correctly. The basis for these guidelines are called the NatHERS Technical Notes. To make sure Assessors properly understand these guidelines, there’s a national qualification for a Certificate IV in NatHERS Assessment (code CPP41212). If your Assessor doesn’t have this qualification, there’s a good chance they’re “unqualified”. Would you let an unqualified mechanic repair your car?
The third part of the this system is a means to make sure Assessors are doing their work consistently.
In addition to the Qualifications, your Assessor should be a member of an Assessor Accreditation Organisation. The largest one in Australia is the Australian Building Sustainability Association, better known as ABSA. These associations have necessary features that make sure Assessors are up to scratch, such as:
- Signed adherence to a Code of Conduct,
- Professional Indemnity Insurance,
- Independent Quality Assurance checks,
- Ongoing training with Continuing Professional Development to maintain competency.
If an Assessor is not a member of an organisation like this, they might not meet all these additional requirements and you might not be covered if things go wrong. Much like making sure your mechanic has business insurance in case their shop burns down while they’re working on your car because they left waste oil sitting around their shop in a dangerous manner, wouldn’t you like to know your Assessor has proper insurance and regular Quality Assurance checks to make sure they’re still following best practices?
The fourth part of the Scheme is the regulatory environment which helps to facilitate industry up-take and use.
Building designs usually change more than once from their first draft to their final construction. The NatHERS Universal Certificate provides Building Surveyors, Contractors, Certifiers & Owners with the specifications used in calculating the Energy Efficiency Assessment. This gives a level of accountability, so all parties can be sure that the building being constructed is the one that was simulated, to make sure the final constructed building still meets the Energy Efficiency Code requirements. Because there are so many parties involved, this extra accountability is important so that everyone can be on the same page. Because this accountability between different parties is so important, an assessment without a Universal Certificate does not comply with NatHERS, and should be returned to the assessor as “incomplete”. It’s similar to hiring a mechanic that gives an itemised receipt of the work done & the parts used, so you can verify they didn’t pull a dodgy one and use knock-off non-compliant parts on your car.
Does it really work?
In short, yes absolutely! When all parts are working correctly, NatHERS is world-class in helping to deliver thermally comfortable homes. It’s our advice that you should always insist on having a NatHERS Assessment for a Residential Energy Efficiency Assessment, in particular a Star Rating. Remember, using an unaccredited assessor may seem like a way to save some money for some ‘cheap’ consulting, but you aren’t getting a complete energy assessment.
Doesn’t your project deserve to be rolling “on all four wheels”?