Compare quotes on system size, panel and inverter brands, estimated annual generation, battery capacity, installation inclusions and total price, rather than choosing the lowest figure alone. Check whether GST, approvals, switchboard work, monitoring, scaffolding and any Small-scale Technology Certificate (STC) discount are included and itemised. Confirm the installer’s licences, Clean Energy Council accreditation, product warranties and workmanship warranty, and ask what happens if the system underperforms. Rebates and certificate values can change, so check current information on energy.gov.au and have the final proposal reviewed by the installer and your electricity retailer.