Residential renewable energy systems are gaining market share. Solar energy may be the most universally available renewable energys ource; it can be used for power generation, space heating and water heating. But renewable energy systems often cannot supply t he fu ll demanded energy load of a home, thus requiring an environmentally conscious back-up fuel. Propane is ideal to integrate a s a back -up fuel for renewable energy systems. This course identifies a new solar water heating system and describes climate and sizing cons iderations for solar water heating. After completing this course the learner will be able to describe why s olar wate r heating is aviable and reliable water heating method for residential homes and discuss why solar water heating is not suf ficien