Narrabundahaus
Residential: Single Dwelling
Passivhaus Plus Certificatoin
Narrabundah, ACT, 2021
Narrabundahaus presents an innovative and well-considered floorplan as a model for contemporary and sustainable living and working. The long-life-loose-fit approach to planning provides a home office and multipurpose space that also functions as a guest bedroom. The attached greenhouse is a biophilic sanctuary that provides enhanced amenity for living and/or gardening throughout Canberra’s often extreme seasons.
The home has received Passivhaus Plus certification. Not only is it highly energy efficient, but it also provides best practice thermal comfort and indoor air quality. The reuse of recycled ‘Canberra Red’ bricks salvaged from the original cottage helps to further lower the carbon footprint, as well as delivering a contemporary design response to its suburban inner south context.
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AIRTIGHTNESS n50 ACH@50pascals: 0.18/h
HEATING DEMAND (kWh/m².yr): 14
COOLING DEMAND (kWh/m².yr): 0
HEATING LOAD (W/m²): 10
PRIMARY ENERGY RENEWABLE DEMAND (PER): 33 kWh /(m2a)
PRIMARY ENERGY RENEWABLE GENERATION (PER): 50 kWh /(m2a) -
LOCATION: Narrabundah, ACT
NCC CLIMATE ZONE: 7 – Cool temperate
NATHERS CLIMATE ZONE: 24
YEAR OF COMPLETION: 2021
TREATED FLOOR AREA (PHPP sqm): 169
PROJECT TYPE: New Build
BUILDING TYPE: Residential: Single Dwelling
CONSTRUCTION TYPE: Timber Frame
CERTIFICATION LEVEL/ ENERGY STANDARD: Passivhaus Plus
THIRD PARTY CERTIFICATIONS: None -
MHRV SYSTEM: Zehnder ComfoAir Q350 HRV
DOMESTIC HOT WATER SYSTEM: Sanden Eco Plus air-sourced hot water heat pump with 250L storage tank
EXTERIOR WALL TYPE, U-VALUE: 140mm timber stud frame with R4.0 glasswool insulation batts and insulated internal service cavity, 0.206 W/(m2K)
FLOOR SLAB TYPE, U-VALUE: 120mm concrete slab 100mm R3.6 XPS insulation, 0.263 W/(m2K)
ROOF INSULATION TYPE, MANUFACTURER: R7.0 blow-in glasswool insulation, Knauf
ROOF CONSTRUCTION: Timber trusses
ROOF ENVELOPE U-VALUE: 0.137 W/(m2K)
GLAZING TYPE, G-VALUE, U G-VALUE: Low-E triple glazed, PressGlass Silverstar (4*/16Ar/4/16Ar/*4), 0.53, 0.58 W/(m2K)
EXTERNAL DOOR TYPE, MANUFACTURER, U D-VALUE:
Logikhaus 68mm timber/aluminium with low-E triple glazing, 1.04 W/(m2K) -
NUMBER OF MODULES: 20
HEIGHT, WIDTH OF ONE MODULE (m, m) : 1.69, 0.996
HEIGHT OF ARRAY: 0.8m
EFFICIENCY: 97%
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The second non-negotiable part of the project brief was to include greenhouse where the resident horticulturalist could spend her time tending to tropical plants that otherwise couldn’t be grown in the ACT climate. Initially conceived as a proprietary freestanding greenhouse, it developed into a custom greenhouse structure attached to, and with direct access from the house through a glazed door. Over 10,000 ‘Canberra Red’ bricks were salvaged from the demolition of the original 1940s cottage and reused in the new building. This reduces the carbon footprint even further, as well as acknowledging the historical context of the neighbourhood.
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One of the main challenges was feeling like we often had to ‘encourage’ the building team to do things better, and to not revert to their default building practices. We would have liked more communication during the project so that we could agree in advance on how certain elements would be constructed. So one of the lessons learned would be to have an adequate set of architectural drawings before commencing construction. The attention to detail required to deliver a certified Passivhaus is obviously higher than for a more conventional project. And ideally this should be reflected in the architectural detailing.
Project Members
ARCHITECT: Envelope Architecture - Michael Tolhurst
PASSIVHAUS DESIGNER: Envelope Architecture - Michael Tolhurst
BUILDER: Walmsley Building Solutions
PASSIVHAUS CERTIFIER: Grün Consulting
STRUCTURAL ENGINEER: ANH Consulting Engineers
WINDOW SUPPLIER: Logikhaus
HRV SUPPLIER: Fantech
AIRTIGHTNESS MEMBRANE SUPPLIER: Pro Clima
INSULATION SUPPLIER: Bradford and Knuaf
ROOFING SUPPLIER: Steeline
BLOWER DOOR TESTER: Aerotight
PHOTOGRAPHER: Benjamin King Photography
Awards and Shortlists
The Derek Wrigley Award for Sustainable Architecture, 2023 – Australian Institute of Architects, ACT Architecture Awards