6-Star energy rating is taking effect in Western Australia on May 1st 2012. The new 6 star energy efficiency regulations are the biggest challenge for builders since the Energy Efficiency regulations were first introduced into the Building Code of Australia (BCA) in 2003. Although it is true, the stringency of the energy efficiency regulations for houses has steadily increased since its induction; the change from 5 star energy efficiency regulations to 6 star is requiring builders and building designers to significantly modify their energy efficiency solutions and method of compliance. The Background Before 6 Star Energy Rating requirements were introduced the easiest method of compliance was to use a Deemed To Satisfy (DTS) method. This involved a glazing calculator – which ensured the glazing requirements were met – and then a simple check box to show that the minimum amounts of insulation were being complied with.
Through studies by industry group As-Built Learning Exchange, in conjunction with leading assessors, such as Sustainability WA, it was shown that this method, although still available under the 6 star energy-rating regulations, is not the best way of compliance due to its restrictive compliance requirements. The use of House Energy Rating Software (HERS) to show compliance with the 6 star regulations was found to be more cost efficient and less time consuming than the DTS method. An added benefit of using HERS software is the possibility of the reduction in compliance costs through the use of solar passive design principles. Compliance Energy Rating or a building Thermal Performance Assessment is the most accurate and flexible method of certification. The new house or addition is modeled using sophisticated computer programs. These models are analyzed and a star rating calculated. The Energy rating depends on:
- The layout of the home,
- The construction of its roof, walls, windows and floor
- The orientation of windows and shading to the sun’s path and local breezes
- And how well these suit the local climate.
- Energy consumption by hot water systems, lights or household appliances is not part of the rating.
Other items that will affect a rating are:
- Sealing – Vented down lights and gas vents will significantly affect an energy ratings
- Colours of material – Dark colours are better in cold climates and light colours are better in warmer climates
- Floor coverings – Tiles show a performance gain in areas where there are high heating loads or where there are full height windows allowing solar access to the tiles.
What the Stars Mean
Zero stars means the building shell does practically nothing to reduce the discomfort of hot or cold weather. A 5 star rating indicates good, but not outstanding, thermal performance. Occupants of a 10 star home are unlikely to need any artificial cooling or heating.
Choosing an Assessor
The right assessor can make a big difference to the compliance of your project. Some things to look for when choosing your assessor are:
- Practical Experience in building and construction methods to ensure cost effective solutions are recommended
- Experience in a variety of HERS programs
- The ability to cover all points of the compliance including the insulation penetration and artificial lighting calculations which come into effect in May 2012
- The ability for your assessor to provide fast efficient service so that it does not delay your building project