Thornleigh Passive House 2024

House Notes – Thornleigh Passive House

Sydney’s first certified Passive House has been lived in four years now!

This two-storey home is located in between a busy road and a train line, but the home is comfortable and quiet due to its insulation and air tight construction. A heat recovery ventilation (HRV) system provides a constant supply of fresh indoor air without the need to open windows (but we do open them when we want to).

The building form maximises solar gain for warmth in winter while maximising shade to keep cool in summer. The north facing roof allows for a 5kW photovoltaic system, sufficient to be energy positive over the year despite significant shading from a magnificent tallowwood tree.

The living spaces are orientated to enjoy the view of the tallowwood tree that is at the geometric heart of the site. A large ‘lift & slide’ door connects the living space to the back deck and yard.

The house is raised to protect the root zone of the tree, and is thus lightweight, lacking thermal mass. This is less significant in a passivhaus than in passive solar. However, the house has 10 internal water tanks to assist in regulating internal temperature. These translucent tanks act as a room divider, framing the entry, while also capturing the sun through a huge north facing window that has a retractable blind for summer sun control. The tanks are not connected to the rainwater tank, as the temperature of rainwater can be problematically low and poses a condensation risk if put straight into the building.

The house has three bedrooms, a study/guest room and two bathrooms (no ensuite). The laundry houses the HRV and hot water tank as well as the usual functional items.

The cost-effective windows are uPVC with an aluminium external skin. Imported, they came triple glazed as standard – double glazing would be a special order and add cost!

The construction methodology allowed for on-site construction while reducing the risk of damaging the air tight membrane. The final blower door test yielded a result of 0.35ACH50. This is well within the Passive House limit of 0.6ACH50 and compares favourably with the average for a new Australian home of 15.4ACH50; 44 times less leaky!

Sustainability Features

Years Open
    • Energy efficiency:
    • Draught proofing
      Efficient lighting
      Efficient appliances
      Energy monitoring
    • Passive heating cooling:
    • Cross ventilation
      Passive solar designed home
      Thermal mass
    • Active heating cooling:
    • Ceiling fans
      Heat exchange ventilation system
      Split system airconditioner
    • Water heating:
    • Hot water heat pump
    • Water harvesting and saving features:
    • Rainwater storage - Above ground
      Low flow shower heads
      Low flow taps
      Drip irrigation
    • Average water consumption per day:
    • 46L/pp/d Sydney Water + ~ 46L/pp/d rain water.
    • Above ground rainwater storage Type:
    • Steel rainwater tank
    • Above ground rainwater storage Size
    • 17500L
    • Energy Efficient Lighting
    • LED lights throughout
      Natural daylight
    • Window Protection:
    • Awnings (external)
      Shade Sails
    • Sustainable materials:
    • No steel structure. Timber structure used No concrete at all (screw piles for footings)
    • Insulation Type:
    • Under-roof
      Internal walls
      External walls
    • Floor Type:
    • Bulk - polyester
    • Floor Rating:
    • R2.0 Greenstuf
    • Under Roof Insulation Type:
    • Insulated panels
    • Under Roof Insulation Rating:
    • R4.95 (total roof) PIR
    • Internal Walls Insulation Type:
    • Bulk – polyester
    • Internal Walls Insulation Rating:
    • R2.0 SoundSolution
    • External Walls Rating:
    • R2.75 (total wall)
    • External Walls Type:
    • 50mm PIR thermal insulation board
    • All-Electric Home?
    • Yes
    • Renewable energy used:
    • Solar PV grid connect
    • Size of PV system:
    • 5.22kW
    • Average Daily Energy Consumption:
    • Daily average (Feb 2020 - Jun 2021): 3.1 kWh used. 3.5 kWh produced. 1.8kWh imported from grid, 2.2kWh exported to grid.
    • Total cost of home when constructed:
    • $900,000
    • Cost estimate of sustainable home/features:
    • minus $22,000 compared to passive solar.
    • Estimate of annual savings:
    • TBD
    • House Size
    • 180m2
    • BAL Rating
    • No BAL rating requirements at time of construction
    • Roof
    • Insulated panel (sandwich panels)
      Metal (Colorbond)
    • Wall Materials
    • Lightweight construction (timber frame)

    • Wall Materials
    • Exterior wall is OSB board with membrane, 50mm PIR panel & fibrecement board.
    • Window and Door Types
    • Clerestory windows
      Tilt and turn
      Triple glazing

    • Window and Door Types
    • uPVC triple glazed with an aluminium external skin; air tight, imported from Europe
    • Universal Design Features
    • 80cm minimum door opening width
      Hobless showers
      Lever handles for doors (no knobs)
    • Number of bedrooms
    • 3
    • Number of bathrooms
    • 2
    • Garden / Outdoors
    • Composting
      Drip irrigation
      Edible garden
      Native plants
    • Waste Reduction Practices:
    • Compost all food scraps
      Swap with friends and neighbours
    • Healthy home features
    • Airtight house design
      Cross flow ventilation
      Heat recovery ventilation (HRV)
      Low VOC paints/sealer/varnish
      Natural light and ventilation
      VOC free paints/sealer/varnish
Thornleigh NSW 2120
    • Housing Type:
    • Standalone House
    • Project Type:
    • New Build
    • Open with support of
    • Australian Passive House Association
    • Builder
    • Red Cedar Constructions
    • Designer
    • Envirotecture

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