Named after an existing native Kowhai Tree which is now central view off the living room – the Kowhai House is perched high on a native clad hillside overlooking the Leith Stream in Dunedin, New Zealand. With the sites marginal soil conditions and difficult access, the building was designed to be simple in form and buildability. The house’s form is a gabled rectangle, but with one roof face of the gable roof sloped up from the ridgeline, not down – providing internal space for mezzanine beds.

The spatial arrangement had to be efficient but comfortable for 4 people to live together with each person having their own space. The house is not expansive, more a comfortable retreat from the city and its challenging climate. Exterior cladding is zinculume corrugate – which gives a crisp juxtaposition amongst the green surroundings. The yellow highlights on the exterior and interior is a visual salute to the Kowhai tree flower. Interior finishes are warm and welcoming with prominent use of NZ pine plywood, kowhai flower highlights with a white painted floor. 

Interfloor structure is exposed to give more height to the space under it, with service lines (wastewater/ventilation ducting) carefully concealed behind a partial floating ceiling aligned with interior cabinetry. We have lived in the house for a year now, and thoroughly enjoy its many spaces, compactness, connection to the exterior, quietness, thermal comfort, and of course the tailored view from the main room to the kowhai tree. 

The house was built by Stevenson & Williams, and certified by Passive House certifier Jason Quinn in June 2018 as ‘Passive House Classic’. Two members of the family are mould/damp/pollen asthmatics – so building and living in a Certified Passive House was not a difficult aim to aspire to and fulfil.

Treated floor area: 116m2 (the area inside of walls)
Heating Demand: 15.4kWh/m2a (calculated 1786kWh of heating energy per year)
Heating Load: 8.2 W/m2 (calculated 0.95kW heater required for the coldest day)
Airtightness Test:  0.1n50 1/h. (blower door test result, 0.1 air changes under 50Pa pressure per hour).
Ventilation is provided with a Mechanical Heat Recovery Ventilation system which is a Certified Passive House component.
The family has taken a while to adjust to the interior temperatures coming from living in a typical NZ house - discarding the woollen jersey’s and wearing t-shirts and shorts through the winter months, and less or no blankets on the beds – just a sheet most of the time.