Before choosing a hot water system, compare storage tanks, continuous-flow gas, heat pumps and solar systems for your household size, available space and energy connections. Check the system’s energy efficiency, running costs, warranty, recovery rate and whether your home needs electrical or plumbing upgrades. Installation must meet Australian safety and plumbing requirements, so use a licensed plumber and, where relevant, a qualified electrician or gasfitter. Rebates and approved-product rules can change, so check your state or territory government and energy.gov.au before buying.