Water heating is an important contributor to household energy use and burden among Aboriginal Community Housing Provider (ACHP) tenants. National data indicate that while nearly 50% of ACHP dwellings use solar thermal systems to heat water using the sun; most use electric boosters that consume high amounts of electricity; and many are non-functional and beyond economic repair at first survey of Housing for Health projects.
Price reductions in rooftop solar over the last decade have made electric water heating a cost-effective alternative to solar thermal water heating when combined with a suitably sized solar PV system. It also has the added benefit of reducing other household energy costs through the self-consumption and exporting of excess solar energy.
The Housing for Health Solar PV Hot Water Trial extension project evaluated the feasibility of using rooftop solar to support the replacement of nonrepairable solar thermal with electric water in a small NSW trial community. Solar PV systems were installed on eight houses, six of which had nonrepairable solar-thermal water heaters replaced with electric systems.
Energy usage monitoring indicated rooftop solar energy production fully offset the electricity usage of newly installed electric water heaters and delivered an estimated 13–48% in electricity savings across all trial houses. A key component of the trail was the involvement of an experienced energy consultant who ensured solar PV systems were correctly sized and worked with ACHP tenants to reduce or shift their energy usage to maximise consumption of free rooftop solar electricity. The trial findings supported moving from solar thermal to electric water heating in ACHP dwellings but only when matched with an appropriately sized solar PV system.