A roof-mounted thermosiphon solar hot water system works by using natural convection to circulate water between the solar collectors and the storage tank, without the need for pumps or complex controls. The system consists of solar collectors, usually flat-plate or evacuated tube panels, which absorb heat from the sun and transfer it to the water inside. As the water heats up, it becomes less dense and rises naturally into the insulated storage tank positioned above the collectors. Cooler water from the tank then flows down into the collectors to be heated again, creating a continuous cycle. This efficient process provides free solar-heated water throughout the day, with an electric or gas booster ensuring hot water availability during cloudy or high-demand periods. Roof-mounted thermosiphon systems are highly reliable, low-maintenance, and ideal for maximizing solar energy use without the need for additional mechanical components.