Solar thermal systems pose some of the most promising renewable alternatives to traditional natural gas and electrical fuel sources. For residential applications, these systems are capable of providing 100% of the domestic hot water load, with excess energy routed to pool heating or space heating applications. Typically, these systems are used to offset between 50-90% of the incumbent water heating fuel source, depending on your latitude. The result is a super-efficient water heating system. For example, your incumbent 65%-efficient water heater, supplemented with a solar thermal system that provides a mere 60% of the load offset, would suddenly become over 150% efficient.
There are a number of government programs for this technology that make it a viable renewable energy source in a number of jurisdictions. Unfortunately, unlike its more popular cousin, solar photovoltaic, solar thermal technology has not received the recognition it deserves.
Solar thermal remains a nascent market with tremendous upside potential for residential, commercial and utility-based energy efficiency programs.