A good solar hot water guide should cover system types, including roof-mounted solar-thermal units and heat-pump systems, which use electricity to move heat from the air into the tank. Consider household size, available roof space, climate, water use, tank location and whether gas or electric boosting is suitable. Some systems may qualify for Small-scale Technology Certificates or state-based assistance, but eligibility and savings depend on current rules and your circumstances. Compare the total installed cost, maintenance and warranty terms, and ask a licensed installer for site-specific advice.