Compare packages using usable battery capacity, expected daily output, round-trip efficiency, inverter compatibility and the system’s warranty terms, rather than focusing only on the advertised price. Check whether the quote includes installation, switchboard upgrades, monitoring, approvals, GST and any available federal or state incentives, as eligibility and savings depend on your circumstances. Ask for estimated annual savings under realistic electricity use and export assumptions, and confirm the battery’s backup capability if that matters to you. Compare several written quotes and have the final design checked by an accredited installer.