Dundonald Street Passive Solar Home in Whangarei, New Zealand, is designed to capture every possible bit of sunlight during winter and naturally exhaust warm air through a central clerestory during summer. The small 119sqm passive solar retirement home is located on a steep east facing 715sqm site with the floor plan orientated on a south north axis. Typically we orientate passive solar houses on an east west axis following the seasonal sun path directions. Given the steepness of the site a south north axis was considered the most practical and economical option.

The central clerestory will bring low angled winter sunlight into the rear of the house, while also cooling the house over summer using stack effect. A thermal mass wall which divides the bedrooms will capture and store radiant energy, heating both bedrooms during winter. Living spaces will receive direct passive solar gain with outlooks onto existing bush area and Mount Parihaka.

The house relies on a suspended insulated light weight concrete floor system with tiles laid over for thermal mass storage. The roof shapes and window positions will naturally ventilate and cool down the interior over summer time.

The house is designed for an anticipated 2700kWhs annually or an annual energy index of approximately 22.7kWh per/sqm, the remaining power will eventually be provided by a 3kW grid connected solar panel system .Internal temperatures will passively peak at 24⁰ during later afternoon mid-winter, with the extreme low being 17⁰ during early morning.

Green technologies and features which have been incorporated into the house are, partial off-site prefabrication, suspended light weight concrete plank system for thermal mass and heat storage, above code insulation for floors, walls and ceilings, insulated glass, electric hot water heating, breathable bio-paints for interior finishes, long lasting low maintenance metal cladding, pine fascia boards at roof and deck edges, energy efficient appliances will be standard items, and water efficient tapware will be used in the bathroom and kitchen.

The combination of passive design strategies, passive solar, passive cooling, energy efficient technologies and an eventual 3kW solar panel system will render the house energy self-sufficient.

+ Location:  Whangarei, New Zealand
+ Programme: Retirement House
+ Client: Private Owner
+ Site area: 715sqm
+ Built area: 119sqm
+ Status: Building
+ Credit: Duncan Firth, Claire Furlong, Saran Chamroonkul



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