The hot water system cost can vary widely depending on the system type, capacity, brand, location and installation requirements. Electric storage systems are often the lowest-cost option to install, while gas, heat pump and solar systems can have higher upfront costs but may reduce running expenses over time. You may also need to budget for pipework, electrical work, removal of the old unit or changes to the installation area. Ask a licensed plumber for itemised quotes, and check energy.gov.au for current rebates or incentives that may apply in your state or territory.