A solar hot water system in Australia commonly costs several thousand dollars installed, with the final price depending on the system type, tank size, roof access, plumbing and whether a booster is needed. Heat-pump systems can have different purchase and running costs from roof-mounted solar systems, so compare the whole-life cost rather than just the upfront price. Small-scale technology certificates or state programs may reduce the price for eligible households, but availability and amounts depend on current rules and your circumstances. Ask licensed installers for itemised quotes and check energy.gov.au for current government assistance.