LNB Orchard Walk homes are energy efficient – designed using passive solar principles for year round comfort. We were intent on developing sustainable and affordable homes that would have low ongoing energy and other costs.
Energy efficient features of the homes
Located within the Aldinga Arts Ecovillage, we were constrained by the bylaws of the AAEV, which include a variety of passive solar design requirements. To these we added:
- 900mm eaves on the north to block summer sun but allow ingress of the lower angled winter sun.
- R2.5 external wall insulation plus thermofoil for added protection against moisture and drafts.
- R4.5 ceiling insulation plus a roof blanket to reflect radiant heat and ensure there were no gaps – this brought ceiling insulation up to R6.
- weather seals on all external doors and windows
- 2KW solar panels – we looked into a community solar system with battery technology but the early-adopter price of this new technology was prohibitively expensive.
- solar HWS with electric backup
- ceiling fans
- LED rather than downlights
- low e-glass in all doors and windows and an aluminium frame. The glazing and frames was a compromise to keep the homes affordable. We offered double glazing as an option and two of the eleven community members decided to install double glazing – one also decided on PVC rather than aluminium frames.
External materials used
Hebel power panel was used on party walls and at the south orientation for its sound and thermal insulation characteristics. Ecogroove – a ‘green tag’ product recognised by the sustainablity council, is a manufactured hardwood weatherboard and is used as the main cladding on a timber frame. This material has low thermal mass – something that works well at Aldinga which can have very hot days but cooling winds at night. The cladding is also low maintenance.
We’d probably do the energy assessment much earlier in the process in our next development as it provides useful input of options available to improve performance. There was some debate over the amount of windows but we felt that any less glass would compromise the aesthetics and liveability of the home: the homes have been designed with an internal private courtyard to allow northern sun into the southern rooms. Reducing the glass would have resulted in darker rooms.
There was also much discussion around the void and stair area. These two areas were also intrinsic features of the design – providing a sense of expansiveness along with raked ceilings and high level, opening windows for cross-flow ventilation. This is not without compromise, as the homes are more difficult to heat in winter and occupants may need to install a curtain or internal awning to help contain heat to the lower zone. Jon Scott, one of new home owners at Orchard Walk developed a 3D representation of the design and here it is. Would we have changed this aspect of the design had we consulted the assessor earlier? Maybe – but the other aesthetic elements and sense of volume created by the void is so intrinsic that it is hard to contemplate the design without this feature.
Energy efficiency is 6.2 to 6.4 – not as good as we were hoping but considered to be comfortable. The behaviour of occupants will also impact on the day to day heating and cooling needs of the homes. We’ll be suggesting well fitted curtains with enclosed pelmets and deciduous trees planted north to shade the windows in summer.
Low ongoing utility costs
Beyond energy use, the homes are designed to have direct plumbed rainwater for all household use. Each home has a 22,000l tank with mains water available as a backup supply. Residents will not receive a service charge for mains water – this charge is directed to the community corporation but they will be on-charged for any mains water used. Recycled water is available for garden use and a shared community garden and fruit trees is being designed in consultation with residents. We also provided LP gas as an option for cooktops. With gas service charges being so high these days, limiting the number of gas appliances in the home means that 2x 9kg bottles will be manageable and ongoing service costs are avoided.
In all I think we’ve been successful in developing sustainable housing that is affordable to buy (average house plus land price was $322,000 including GST); affordable on a day to day basis; and is complimented by shared community resources that have the capacity to make an individual’s resources stretch further.