A solar hot water system uses roof-mounted collectors and a storage tank, usually with an electric or gas booster for cloudy periods. When comparing options, consider your household’s hot-water use, roof space and orientation, available sunlight, local climate, installation costs and ongoing maintenance. Heat-pump hot water systems are another efficient option where roof access or solar exposure is limited. Rebates and small-scale technology certificates may be available, but eligibility and savings depend on the system, location and current rules, so check energy.gov.au and speak with a licensed plumber before deciding.