Compare several written quotes from Perth installers, including the panel and inverter brands, system size, expected output, installation costs and warranty terms. Check the installer’s current licences, insurance and Clean Energy Council accreditation, and look for relevant local experience. Ask whether the proposed system suits your roof, electricity use and Western Power connection requirements. If you are considering a battery or exporting energy, confirm the likely costs and payment rates with your retailer, as these can vary. You can also check reviews and verify key details with the installer and the relevant official authorities before signing.