6 Star Energy Efficiency: How Does It Work?

In May 2012 the Federal government with the co-operation of all State governments brought in the 6 star benchmark for all new homes built in Australia. The backbone of this program is the NatHERS (Nationwide House Energy Rating Scheme) which shows houses (prior to being built) as a rating from 0 to 10 stars, this is known as an ‘Energy efficiency certificate’.

The energy efficiency certificate shows home owners the energy efficiency of a house, same as fridges, washing machines, cars, ovens, microwaves, etc. Using the house plans, the assessor will work out how much energy the house uses. Areas assessed are the materials used to build the house, orientation, windows/frames, window/floor treatments, insulation, door/window seals, air movement & external colours using advanced 2nd generation software.

The rooms of a house are designated tags as to how they are used, EG: Kitchens create heat, Bathrooms, En-suites & Laundries don’t require heating, Lounge rooms are used throughout the day & bedrooms are used at night. The software calculates how much artificial heating & cooling each of these areas will require for the occupants to feel comfortable when they use them throughout the whole year, day in/day out for all seasons. The star rating provided shows how efficient (in Mj/m2) the house is, which really means how much extra will the owner have to pay in utility bills to feel comfortable in the house all year round. The lower the star rating the more energy (EG; power/gas) the house will need for the occupants to feel comfortable, the higher the star rating, the lower the utility bills.

Things that can reduce a star rating are long East & West walls with lots of glazing (windows/sliding doors) without adequate shading (eaves/verandahs), large passageways & entries as these are connected to living rooms or kitchens/bedrooms which then require artificial heating & cooling, orientation of the house & what rooms face what direction (homes that have the living areas to the North usually rate better as the natural heating & cooling from the sun reduces the amount of artificial air temperature if the shading to the glazed areas are correct) unsealed windows/door & wall vents for gas bayonets.

All homes in Australia are designated a ‘Climate zone’ which is dependent on their post code. The software then knows that if a home is in ‘XXXX’ post code & it faces XXX degrees & is built to the plans supplied it will give X.X stars. Some climate zones require more insulation to the ceiling & walls, some require less, some require upgraded glass (double glazed/low emissivity) that prevents solar heat gain from entering certain rooms & some require different external wall/roof colours to achieve 6 star compliance.

In the outer city area of Perth, homes that may require extra insulation properties can be within climate zone 47 & 58 which are the Harrisdale, Champion Lakes, Hilbert, Piara Waters, Byford, Caversham, Jane Brook, Brabham, Brigadoon, Alkimos, Jindalee, Butler, Iluka, Burns Beach, Mindarie, Eglinton, Yanchep, Aveley areas, (NOTE: As the climate zones don’t just cover the post codes, they will encroach other areas, therefore, depending on the actual address of the home it may be in a zone that requires less treatment).

In all cases, the home owner can be assured that the energy efficiency assessor will work towards compliance at the minimal expense.

And remember with a free and competitive quote, you really can’t afford not to get in touch with our drafting department and 6 Star energy efficiency assessors to discuss your next job.

Due to constantly evolving legislation the information provided within this blog may no longer be valid. The advice given on this site is general in nature and does not take into account your specific circumstances. Please email one of our building surveyors to check what is right for you.