What falls outside the stars
By paying attention to little details that fall outside the star rating systems, Henley Homes has created an affordable and realistic family home with zero energy costs in operation. Jonathan Green explains.
There is no denying that the star rating systems used around the country have been positive for the construction industry. New products, better processes and clever designs have all spawned from the need to meet and surpass rating systems, and are significant in driving environmental reform.
Although there are mandatory requirements in every state, many individuals and associations continue to exceed minimum levels and demonstrate what is ultimately possible.
These people should, and will, be applauded, as it is through these efforts that continual development occurs in the industry.
However, as we have discussed on a number of occasions in Building Connection, much of the current star rating criteria essentially relates to thermal efficiency rather than energy efficiency. The net result is a building that is unquestionably more thermally efficient – but doesn’t necessarily equate to true energy efficiency once it has been fitted and is in use by occupants. Elements such as air tightness, indoor air quality, heating, cooling and more, are all factors that contribute to a home’s energy efficiency and living quality – yet are not addressed in the current star rating systems.
Henley Homes is making a conscious decision to tackle these issues with the construction of the ‘Selandra Community Place’ in Melbourne’s south east. The house still manages to achieve an 8-star rating, yet has also focused on a number of small – but important – factors to achieve what is known as a ‘zero energy’ home.
Quite simply, this is a house that should generate more power than it uses, thereby offering true energy efficiency, an excellent environmental result, no power bills and a tangible (let alone immediate) benefit for the occupier.
Adam Selvay is the energy, sustainability and innovation specialist for Henley Homes and worked extensively on the Selandra project.
“We see this house as a display home for sustainable living,” says Adam. “That includes how to design, how to build and – most importantly – how to live in a sustainable manner.”
The house is double-storey, has four bedrooms, multiple bathrooms and large open living spaces. Including the garage, it comes in at approximately 330m² – a very decent sized property for a large family.
It is a combination of some tried and true principles of sustainable living and design, with some new concepts, materials and processes thrown in for good measure.
It was officially launched in March and is now open as a display house, complete with educational signage and material to help explain its many features. It is also plays host to a number of regular community and council events to demonstrate its performance in operation.
What Henley has achieved is a house that is high in thermal and energy efficiency, but also realistic in cost and operation to the average household.
“I think it is important that the industry keeps developing and pushing the envelope to create better houses, but there are important elements that fall outside the star rating systems,” says Adam.
“We still recognise the importance of thermal efficiency and have addressed that in the most cost effective manner we can. For example, the house contains a triple level of insulation through a mixture of external walls, internal walls and cavity filling achieving an approximate R8 rating – but we also believe there are many small details that should be addressed as well.
“Ultimately, we want it to be efficient in operation and that is why we have paid so much attention to little details and worked hard to understand what will make things as simple as possible for the home owner.
“Things like air tightness are critical to a home’s performance, yet no one gets any credit for addressing it. You can build with the most thermally efficient materials possible, but if there are gaps around windows or doors or light fittings – as small as they may appear to be – then you still allow heat loss or gain and undermine the performance when people start living in there.”
Equally, features like permanent shading – in the form of attractive wooden panels adhered to the external walls – ensures the home owner receives the best possible results with no personal effort.
“We have built properties in the past that have extendable external blinds to provide shading, but the simple fact is that many people simply do not utilise them,” says Adam. “Human behaviour is difficult to factor in, but needs to be done, and something like this means that the feature will work regardless of who is living in the house and how they would operate it.”
Simple features such as a highly energy efficient heating and cooling system also add great benefits to the house in operation. This has been installed in zones so only parts of the house can be heated or cooled depending on the need – thereby reducing unnecessary use.
Again – these elements do not fall under the star rating system.
Indoor air quality has been addressed through a heat recovery ventilator and carefully designed natural air flow with large windows that accentuate air movement.
The house has even been fitted with appliances to provide practical testing in performance and they have been selected to reflect a realistic use. They are not the best appliances on the market, but are the most efficient in a typical family budget constraint.
Further to the functionality features of the house, Henley ensured the construction was as environmentally friendly as possible by sourcing specific materials wherever possible. These products are easily available, but don’t necessarily come to mind when specifying for a traditional family home. The concrete slab is made from eco-crete (which uses an industry by-product in the mix to reduce waste), the carpet is manufactured from recycled plastic bottles, and the back decking is a composite that uses recycled shopping bags.
“As a volume builder we can’t construct using second-hand materials because we need to be able to replicate our houses in all areas at all times. But we can use products made from recycled materials and that is something we have paid attention to here,” Adam explains.
It all amounts to a very interesting project. While no one would suggest that achieving stars is a bad thing, it is worth remembering that there are many things you can do to improve the energy efficiency of a home that are sensibly priced and fall outside the star rating system.
Working with this mindset provides valuable and tangible benefits to the consumer, and sets you apart from the pack in a manner the average person can truly appreciate. Within the race to chase stars for the future, it is perhaps worth remembering the ‘here and now’ and offering something to the customer that will benefit them immediately.
Selandra Community Place