NABERS, the National Australian Built Environment Rating System, and NatHERS, the National House Energy Rating Scheme, are Australian Government Initiatives designed to reduce greenhouse gas emissions by increasing the efficiency of buildings. These two schemes have a number of differences:
What do the Systems Measure?
NABERS measures the environmental performance of a building against a set of benchmarks. It measures a building’s energy and water efficiency, indoor environmental quality and waste management.
A NatHERS rating measures the amount of energy (relative to the size of the home) required to heat and cool the individual dwelling throughout the year.
How do they work?
NABERS examines a building’s historical and current water usage, energy usage, and waste management processes and compares these against a set of benchmarks to produce a rating that is current for one year.
NatHERS collates all the relevant features of a building, such as climate zone, orientation, building materials, window placement and size, room type, insulation levels etc, and runs these through an approved software. The software effectively calculates the temperature of each room thoughout each day of the year and uses this information to caclulate the energy that would be required to heat or cool the home in one year.
What is a maximum rating?
In NABERS, a maximum rating is 6 Stars, demonstrating market leading performance, and this rating is current for one year.
With NaTHERS, the rating is out of 10 Stars, however, only 6 Stars is required for compliance, and the rating does not need to be repeated once certification has been achieved.
Are they both compulsory?
NABERS is a voluntary scheme, however, a NABERS rating is required under the Commercial Building Disclosure Scheme for sellors and lessors of office space greater than 2000 square metres. NatHERS fits into the compulsory National Construction Code Series. Under the Energy Efficiency Provisions, every new home or major renovation needs to obtain a software produced minimum 6 Star Energy Rating (for more information, see here). There are slight State and Territory differences in application of this law, but this is the basic standard.
What is the intended Application?
NABERS is aimed primarily at Offices, Hotels, and Shopping Centres, although it can also be used for homes.
NatHERS is aimed primarily at homes (houses, townhouses, apartments and units), and cannot be used to model commercial dwellings such as assembly halls or office blocks.
Is Self-Assessment possible?
Self-assessment is possible with NABERS, however it does begin to get quite complex when assessing a large building. You can self-assess your home with NABERS here. NABERS recommends only using an Accredited Assessor as then you obtain an accredited rating that can be used for marketing purposes.
Self-assessment is not possible with NatHERS, as only Accredited Assessors, who are trained in the use of the required software, are able to produce ratings acceptable for Certification of a home.
For more information on NABERS, see their informative website.
For more information on NatHERS, see here, or contact BERA for Ratings, Assessment or Advice.