The Solarhome Project was established by Australian building designer/entrepreneur David Macfarlane with the aim of creating a stylish self-sufficient house – with all the mod cons and comfort expected of a luxurious modern home – that is not only fire-proof and cyclone-proof, but additionally, so energy-efficient that it can be 100% electrically powered (including heating, cooking, and hot water) entirely by an off-grid solar-charged battery without the need of gas, oil, a wood fire, a fossil-fuel-powered generator, or grid backup.  In other words, a genuine zero emission house.

Tamar Solarhome is the prototype of this design, which was built in Tasmania (during 2016) to test its performance in a challenging climate.  The Solarhome is super insulated, super energy efficient, and super robust.  It essentially consists of a 150mm-thick concrete outer shell (including the roof and floor), with an unbroken internal layer of 250mm-thick polystyrene insulation in the walls, ceiling, and floor, triple-glazing, airtight construction, heat-pump-generated hot water and internal air heating, 25 high-performance solar panels, and a massive battery which stores enough electricity to power an occupied house for 5 days, during winter, with no solar input at all.

As you can probably imagine, it turned out to be a very expensive build for a relatively small house, and an ethanol fireplace had to be added for ambience, plus a gas barbecue and wood-fired pizza oven for extra cooking options, so it wasn't as emission-free as we had hoped.  But the house operated faultlessly as an Airbnb for almost five years without needing a generator.  However, a petrol-powered backup generator eventually had to be installed after an inadvertently plugged-in electric vehicle drained the house battery one night, followed by a winter week without sunshine, resulting in a house that couldn't be used for more than a week.

So we finally discovered the problem with and limits of a solar-powered system – it can't supply electricity on demand and the amount of electricity it can provide is extremely limited.  But we learnt a lot about energy efficiency.  And a modern solar-charged battery system is great technology for small off-grid houses.  The next prototype, the Solarcabin, to be built in the Hunter Valley north west of Sydney before the end of 2022, will be considerably less ambitious; a very affordable 36m² cabin; easily buildable on any site, thermally comfortable in any climate, and designed to be totally self-sufficient for power, waste, and water.  Detailed plans will be available for purchase on this website when the prototype is completed.