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Sustainable House - Retrofit House

By Tony Wolfe

For a long time I have been passionate about energy efficiency so when I purchased this property which was a “renovator’s delight”, it seemed logical to achieve the highest possible standard that I could economically obtain.

I have worked in the power generation industry all of my life and I could foresee the rapid increase in energy prices coming so the intention was to produce a house that left minimal footprint and relied little on services. This house renovation was a part time interest that took approximately 5 years to complete. As I carried out a lot of the grunt work myself under the direction of my builder, it is very satisfying to sit back and enjoy the benefits.

I am an Electrician specialising in lighting so great detail went into careful selection and semi-automation of the electrics throughout the house. I am quite proud of the fact that over a 12 month period, the usage costs of electricity, gas and water has been less than $400 in total. Incorporated in the design is a 4.5kW PV system, rainwater storage tanks, solar storage hot water and low maintenance gardens.

The inclusion of electrically operated clerestory windows promotes cross flow circulation in hotter weather drawing air across a pond located on the south side of the building. The carport is fitted with a power supply to allow charging of my plug-in hybrid vehicle. Synthetic lawns (including the nature strip) ensure there is never a need for mowing.

Cost estimate of sustainable home/features


Total cost of home when constructed


Estimate of annual savings


BAL Rating

BAL – Low: There is insufficient risk to warrant specific construction requirements.Roofing materialsMetal (Colorbond)

Wall materials (external and internal)

Insulated panels or blocks

Window and door types

Awning / Bi Fold / Clerestory windows / Double glazing

Recycled and reused


Insulation - Under roof

Type: Air Cell Rating: R2.0Insulation - Ceiling Type: Bulk - glass wool Rating: R5.0Insulation - External walls Type: Insulated panel system Rating: R6.0Insulation - Internal walls Type: Bulk - glass wool Rating: R2.5

Healthy home

Cross flow ventilation Indoor plants for air filtration Natural light and ventilation No carpets

Energy star rating

First Rate - Energy star rating 8

Renewable energy

Solar PV grid connect 4.5kW

Solar hot water (evacuated tube)

Passive heating cooling

Cross ventilation Shading

Split system airconditioner

Energy efficiency

Efficient lighting Efficient appliances Smart home features

Electric vehicle

Mitsubishi Outlander Plug-In Hybrid Electric Vehicle (PHEV)

Water harvesting and saving

Above ground rainwater storage Colorbond rainwater tank Low flow shower heads Low flow taps

Garden/OutdoorsNative plants Water wise plants Synthetic grass

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