There are a wide range tools and programs available to rate the energy efficiency of a home. One of the best-known is the Nationwide House Energy Rating Scheme (NatHERS). You may have had one of these assessments completed on a new build or on a home with significant renovations happening.
But what are the similarities and differences between NatHERS and the Residential Efficiency Scorecard?
NatHERS is a program that provides a thermal performance energy star rating, out of 10, for new homes before they are built or undergoing significant renovations.
NatHERS focusses on assessing the thermal performance of the building shell using oneof the accredited simulation tools, including AccuRate, FirstRate5 and BERS Pro.
In simple terms, the NatHERS program looks at what materials your home is made of, its orientation, overshadowing of surrounding buildings, climate, and other site-specific factors like those. As of 2022 it doesn’t consider any fixed appliances. But with changes to the National Construction Code (NCC) and implimentation of Whole of Home ratings, that might change very soon.
The Scorecard is slightly different. It’s a unique program that provides a cost-based energy star rating, out of 10, for your home. In the same way as a fridge or washing machine has a star rating, a Scorecard rating represents the energy cost of the fixed appliances in your home.
Each method has features that the other does not have, because they service different needs.
For example, the Scorecard includes appliances such as hot water systems and provides upgrade options or recommends solar PV. Most NatHERS tools don't do this.
NatHERS provides a very flexible tool to design a new home to ensure the building shell (for example, window locations and building materials) performs well. Both programs treat the building shell similarly. The Scorecard building shell rating is a simpler version of a NatHERS rating and has been tested in line with NatHERS to confirm the two tools are consistent.
So, a home with a good NatHERS building shell rating should also rate well under the Scorecard building shell elements.
In summary then:
NatHERS:
1. Was developed for new homes and extensive renovations, providing a rating to demonstrate that it meets minimum energy performance requirements (currently 6-star or equivalent)
2. Is most commonly used for regulatory purposes under the National Construction Code (NCC) of Australia
3. Currently assesses only the building shell
Scorecard:
1. Was developed for existing homes, providing a rating and upgrade options for the occupant
2. Can be used for new homes from plans
3. Is voluntary and not part of any regulatory program or the building code (not yet, but stay tuned)
4. Assesses major fixed appliances along with the building shell
