While many would see eight acres of native bushland in the Blue Mountains as land best left untouched, Anderson Architecture saw an opportunity: to design and test a sustainable, self-sufficient and bushfire-resilient home that could operate entirely off grid. The result is Off Grid House, an experimental family residence and research project that has significantly reduced energy use while advancing the practice’s expertise in low-carbon residential design.

Designed and built by Anderson Architecture director Simon Anderson for his own family, the house is guided by a clear principle: a site’s greatest challenge should become the source of its innovation. The steeply sloping bushland site offers dramatic escarpment views to the south, but orienting the home to capture them would typically mean sacrificing optimal solar access. Rather than compromise, Anderson resolved the issue by dividing the house into two distinct skillion-roofed volumes, oriented in opposite directions and programmed for different uses.

The sunlit volume contains the sleeping quarters, where optimal orientation delivers strong passive thermal performance throughout the day to enhance comfort at night. The second volume, housing the open-plan kitchen, living and dining areas, is oriented towards the southern slopes to maximise views. Despite its reduced access to direct sunlight, this ‘living box’ supports energy generation, with a 6.7kW solar PV system installed on its roof, paired with a 27.6kWh battery for storage.

A suite of passive and active systems ensures year-round comfort with minimal energy input. Double glazing, heavy insulation and underfloor heating allow even a small wood fire to adequately heat the home during winter, with firewood sourced directly from the site and surrounding bushland. A heat recovery ventilation system further improves efficiency by redistributing warm, fresh air generated from stale exhaust air between living and sleeping zones as required. Black oxide insulated concrete floors provide thermal mass, supporting temperature stability across seasons.

Material selection reinforces the project’s low-carbon ambitions. The house achieved net zero CO₂ emissions during construction and continues to operate at net zero. Zero-VOC paints were used throughout, while stringy bark timber harvested on site features in the internal structure, loft floor joists, kitchen bench and joinery. The home achieves an 8.2-star NatHERS thermal performance rating.

The architecture responds directly to its bushland context. Drawing inspiration from the escarpment’s weathered rock faces and sandstone undercrofts, the living zone incorporates large sliding glass doors on two sides, creating a cave-like cantilever that blurs the boundary between indoors and the sunlit deck beyond.

Given the site’s exposure to bushfire and termites, resilience was a key driver of the design. The home is constructed using a fireproof concrete structure, while low-carbon fibre cement board cladding and decking deliver the appearance of timber with the durability required for BAL 40 and BAL FZ performance. A bespoke 2.4-metre external metal screen can be winched into position to provide protection from heavy rain or act as a flame barrier in the event of a bushfire. Additional windows are safeguarded with motorised fire screens.

Water security is managed through rainwater harvesting, with both roofs feeding 30,000 litres of on-site storage and future plans to add further tanks beneath the deck to capture overflow and manage drought periods. Waste is treated via an on-site worm farm, reinforcing the home’s off-grid independence.

Contemporary in form yet deeply responsive to place, Off Grid House demonstrates how architecture can reconcile comfort, resilience and environmental responsibility. More than a family home, it stands as a working prototype for the future of off-grid living—one that treads lightly on its surroundings while offering a compelling model for sustainable residential design.

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