Grevillea House 2024

House Notes – Grevillea House

We aimed to build a comfortable home with a touch of luxury, which prioritised function over form. A forever home which is very low maintenance and will be suitable for us as we age or have mobility issues. A home which does not need large inputs of external services such as electricity gas and water.
We designed the home ourselves to suit the land, making best use of the small block and an unrestricted Northern aspect.


North facing timber frame on concrete slab. Colorbond gable roof for simplicity, low maintenance, ease of solar installation, and rainwater harvesting. Front wall cladded with Hebel panels and other walls with Scion Stria compressed cement boards.

A Rammed Earth Wall (REW) forms the central spine of the house and is completely within the insulated envelope. Sunroom on the NorthEast corner.

Windows are double glazed and appropriately sized.

The garage is separate from the house to avoid thermal bridging via a common slab with the home and to avoid compromising indoor air quality.


Heating is by solar gain through Northern windows and the sunroom. The sunroom helps to heat the home and is a cosy retreat on sunny winter days. It is well insulated and has a low thermal mass. It’s not artificially heated or cooled but can be used most days of the year. On cold nights it is isolated from the main home with a double glazed sliding door and pelmeted curtains to stop heat loss from the main section of the house. On hot days during summer the sunroom doors are opened to outside but the door to the house is closed.

The REW soaks up any excess heat from solar gain thus stabilising the temperature. This, combined with sensible sized windows, airtightness and the high level of insulation, means the indoor temperature will only drop 1 or 2 deg overnight in winter without artificial heating. The main bedroom and ensuite don’t need supplementary heating as they adjoin the REW which never drops below 19 deg.

A single 6kW split system can be used for heating if prolonged cold weather requires it. The Split System use can be limited to daytime when some solar power is available. However, we have found that if the sun is out the house gains warmth anyway, and extra heating isn’t needed. Conversely when heat really is needed, it is when there has been no sun for days. Despite occasional cold snaps during Spring, heating isn’t needed from the end of August through to June.


Cooling is rarely needed, thanks to insulation, airtightness, shaded windows and the moderating effect of the REW, which again soaks up excess heat during the day, but is now able to be cooled at night by ventilation. A ShadeForm blind shades the kitchen and sunroom window which don’t have eaves. Having no eaves gives the opportunity to open the blind and let sunlight in during unseasonal weather.

DC ceiling fans are used to increase comfort when inside temperatures rise, with the airconditioner called on for those few occasions when the home gets above 24degrees.

6.6kW of grid connected solar was installed while the house was still under construction.
Electricity use including self-consumed solar averages 5.0kWh per day over the year and an average of 24kWh per day is fed back into the grid. Despite falling feed in tariffs our electricity bill gets credited 11 months of the year.

Cooking is by an induction cooktop and an electric oven.

An evacuated tube HWS provides ample hot water most of the year and rarely needs boosting. All hot water pipes are insulated. The tank is inside, minimising heat loss. An on-demand return system on all hot taps sends the initial cold water in the hot water pipes back to the rainwater tank saving time and valuable water.

The house and garden run on 100% rainwater via a pressure pump. No filtering to the house has been needed as gutters are kept clean and water is screened when entering the tank. Mains water is available.

Ensuite has an enclosed shower room with a window. This keeps steam in the shower area preventing mould and fogging up the mirror. Being able to dry in the warm shower area is luxury.

Wifi enabled curtains can be operated when not a home.

Low level LED skirting lighting in selected areas means bright lights don’t need to be used when getting up in the middle of the night.

An upstairs room makes use of the roof space and gives easy access to the ceiling and storage via an insulated door.

Sustainability Features

Years Open
    • Energy efficiency:
    • Draught proofing
      Efficient lighting
      Efficient appliances
      Energy monitoring
      Smart home features
    • Passive heating cooling:
    • Cross ventilation
      Deciduous planting around house
      Passive solar designed home
      Thermal mass

    • Passive heating cooling:
    • Sunroom which can be opened or closed to house
    • Active heating cooling:
    • Ceiling fans
      Split system airconditioner
    • Water heating:
    • Solar hot water (evacuated tube)
    • Water harvesting and saving features:
    • Rainwater storage - Underground
      Low flow shower heads
      Hot water recirculation
    • Average water consumption per day:
    • 101 litres
    • Underground rainwater storage type:
    • concrete tank below garage
    • Underground rainwater storage Size:
    • 22,000 litres
    • Energy Efficient Lighting
    • LED lights throughout
      Natural daylight
    • Window Protection:
    • Adjustable Shading
      Deciduous tree/vegetation
      Shade Sails
    • Sustainable materials:
    • No waste skip used during construction, wood, steel, plasterboard, tile offcuts and plastic all recycled. Burnished and oiled concrete floor, gives a durable marble like finish without tiles or grinding. Marmoleum in sunroom (no off gassing vinyl).
    • Recycled and reused materials:
    • Bathroom cabinets
    • Insulation Type:
    • Under-roof
      Internal walls
      External walls
    • Ceiling Type:
    • Bulk – glass wool
    • Ceiling Rating:
    • R5.0
    • Under Roof Insulation Type:
    • Anticon blanket
    • Under Roof Insulation Rating:
    • R1.5
    • Internal Walls Insulation Type:
    • Bulk – glass wool
    • Internal Walls Insulation Rating:
    • R2.0
    • External Walls Rating:
    • R2.5
    • External Walls Type:
    • Bulk – glass wool
    • All-Electric Home?
    • Yes
    • Energy star rating:
    • 8.1
    • Renewable energy used:
    • Solar PV grid connect
    • Size of PV system:
    • 6.6
    • Average Daily Energy Consumption:
    • 2.5kWh
    • Total cost of home when constructed:
    • $320000 constructed 2019
    • Estimate of annual savings:
    • $2000
    • House Size
    • 237 m2
    • BAL Rating
    • BAL – Low: There is insufficient risk to warrant specific construction requirements
    • Roof
    • Metal (Colorbond)
    • Wall Materials
    • Aerated concrete
      Lightweight construction (timber frame)
      Rammed earth
    • Window and Door Types
    • Awning
      Sliding windows/doors
      Stacking windows/doors
    • Universal design accessability
    • Adaptive design
      Universal access
      Wheelchair accessible
    • Universal Design Features
    • 80cm minimum door opening width
      Flush thresholds (no lip) to all external doors
      Hobless showers
      Kitchen bench/table for wheelchairs to access (75-85cm high)
      Lever handles for doors (no knobs)
      No Corner cupboards
      Pull out shelving easily accessible in wheelchairs
      Ramps and path gradients must be less than 20:1
      Remote power open and close doors
      Semi recessed basins
      Shower head on rail for various heights
      Space around toilets for ease of access in wheelchairs
      Tapware to be easily accessed from outside the shower
      Window openings easily accessible

    • Universal Design Features
    • Low level LED lighting in skirting Large pantry with open shelving. Burnished concrete floors on Northern side with carpet in the 2 Southern bedrooms. Ducted vacuum system Slate paving from local Quarry
    • Number of bedrooms
    • 3
    • Number of bathrooms
    • 2
    • Garden / Outdoors
    • Community vegetable garden
      Edible garden
      Local indigenous plants
      Native plants
      Wicking beds
    • Waste Reduction Practices:
    • Book exchange/library
      Compost all food scraps
      Make jams/conserves
      Swap with friends and neighbours
      Waste free/reduced construction site
    • Healthy home features
    • Airtight house design
      Chemical free cleaning products used
      Cross flow ventilation
      Natural light and ventilation
      Natural oil sealer/finishes

    • Healthy Home
    • Ducted Vacuum System
Aldinga SA 5173
    • Housing Type:
    • Standalone House
    • Project Type:
    • New Build
    • Builder
    • owner
    • Designer
    • owner builder

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