Explaining the Housing Energy Rating System – What Does it All Mean?
Deciding you want to build a sustainable home is the first step in a process that can feel complex and overwhelming. You may have heard of a range of terms in relation to different housing rating systems like NABERS, NatHERS, or Green Star and wonder what they are all about. Each rating system is different, and relevant for different purposes. Here we break down each of the systems that are relevant in WA for you:
National House Energy Rating Scheme (NatHERS) http://www.nathers.gov.au/ is a 10 star rating system that analyses a building’s design for its energy efficiency. It is a great guide to help ensure that your design meets your energy efficiency expectations. It gives you the chance to see what impacts the energy efficiency of your home so you can design to accommodate this. They have a great video to explain their system here: https://www.youtube.com/watch?v=Du4gSvFazWs This is a great starting place on your journey to a more sustainable home.
Similar sounding to NatHERS is the NABERS system (the National Australian Built Environment Rating System). The standard NABERS system does not assess individual residences but larger developments, however there is an offshoot of NABERS for homes that is useful to assess how your home rates. You can enter data for your current home and it will assess how efficient you are in different aspects of your home, such as appliances, lighting, hot water, heating and cooling etc. Once you have filled out the relevant sections it will provide you with a NABERS star rating out of 6. It will also provide tips for you to improve your home’s performance. Have a look at it here: http://home.nabers.com.au/ This system is particularly useful as it is based on actual performance data and not projections.
Green star is a rating system that qualifies how buildings meet the Green Star sustainability benchmarks and assigns it a star rating out of 6. It is an internationally recognised accreditation system run by the Green Building Council of Australia https://new.gbca.org.au/. Green star rates your building on both the construction and operation of the building. It takes a more holistic approach to how a building is considered ‘green’ rather than being purely based on energy usage.
With Green Star rating, there are 9 categories that you are assessed on:
- Indoor Environment Quality
- Land Use & Ecology
Currently the green star rating system cannot be used to rate individual free standing homes, but it is something that is currently being worked on and will be available in the near future. Regardless of this, the Green Star system is still useful in the way that it expands your understanding of what is sustainable in building practices. We often get focused too narrowly on just the energy consumption aspect of sustainability to the point that we overlook other features. Even if you cannot pursue a Green Star rating for your individual home it is definitely worthwhile to have a look at the GBCA website and get an understanding of the potential impact of your building. They have some interesting case studies, in particular apartment developments, on their website that can demonstrate many different approaches to building sustainability that you could incorporate into your home. Check out their website here https://new.gbca.org.au/green-star/rating-system/design-and-built/ and another useful website by them https://www.livinggreenstar.org.au/