The Building Designers Association of Victoria’s (BDAV) 10 Star Challenge is aimed at giving partici pants the knowledge of what it takes to reach the ‘holy grail’ of energy effi ciency, where no external energy inputs are required for heating and cooling to maintain year-round internal comfort.

While we don’t expect that large numbers of 10 star houses will be built straight away, those professionals who know what it takes to reach this level will be able to create 6, 7 and 8 star designs with their eyes closed and their hands tied behind their backs.

Seven and 8 star houses equipped with efficient white goods, electronic equipment and lighting will require such modest energy inputs that small photovoltaic systems or other renew able power sources will more than match demand.

Different responses are required in different climate zones around the country but on much of our home turf, BDAV members should be able to design homes that negate the need for any mechanical cooling.

The dumb approach to improving energy efficiency is to throw money at the problem. Anyone who continues to maintain that addressing energy effi ciency is difficult, expensive and will impact negatively on housing afford ability is only doing so because they haven’t equipped themselves with the understanding of how easy it is.

Designers well-versed in the science of thermal performance of building fabric can impact positively on housing affordability if the basic rules are fol lowed. The capital cost need not be any greater for the structure, the pur chase of air conditioners can be avoid ed and significant savings will be deliv ered in ongoing utilities accounts.

The principles behind the 10 Star Challenge encourage the use of ener gy rating software as a design tool as opposed to running a rating at the last minute in order to satisfy minimum scores for regulatory compliance.

Careful, considered use of one of the three rating tools that comply with the NATHERS protocol will enable the tweaking of specifications to deliver the most cost effective results. It is unrea sonable to expect that one size fits all and site-specific constraints can be best addressed by using the rating model to extract the simplest most cost effective solutions. There is no shadow of a doubt that a little time applied to ener gy modeling will save thousands of dol lars in unnecessary over-specification of insulation and window systems.

Before proposing the challenge, I felt it prudent to ensure that I didn’t embarrass myself by not being able to achieve 10 star scores myself. High performance windows are needed as are reasonably high U-values for added insulation. However, what we found was that when the specification was stripped back to minimum indus try standards with single glazed win dows, the worst score we managed was 8.2 stars.

This scenario has been used to illustrate the approach in recent work shops delivered by the BDAV with the assistance of Sustainability Victoria to more than 700 designers and raters. The large numbers of BDAV members attending the workshops confirmed an overwhelming enthusiasm to ensure that they avail themselves of every opportunity to add to their knowledge base.

My house, now known as ‘the house with no bills’ has after two years of occupation achieved the goals set to have no net outgoings for energy and services and be carbon neutral if not carbon positive in operation. A 7 star house design which needs no summer cooling is kept comfortable in winter with passive solar gain and sup plemented by solar hydronic domestic hot water/heating system. Credits from electricity feed-in tariffs more than cancel out the outgoings for electricity as well as property connec tion charges plus a black water treat ment service contract and chainsaw costs for cutting timber to fuel the high efficiency backup boiler.

The thermal design focused on ensuring that summer cooling appli ances were unnecessary and although that made a minor detriment to winter performance the only fuel required is timber taken from a completely sus tainable, renewable on site reforesta tion program which sequesters much more CO2 than will ever be emitted by the boiler.

Although 10 star houses are unlikely to litter the landscape, their 7 and 8 star siblings should proliferate and start to deliver a standard of accommoda tion that we have been too lazy to understand because a relatively benign climate combined with abundant, cheap, dirty electricity in combination with cheap natural gas has allowed us to design poor quality housing and make them comfortable by pumping in huge quantities of energy.

10 star champions will be able to lead the industry forward to provide cost effective, high performance solutions.

Tim Adams is president of the Building Designers Association of Victoria, whose objective is to advance the profession of building design, by offering cost-effective, quality, membership services and benefits to meet the needs of this growing sector of the building industry community.