Inter-Island Solar Supply (IISS) is one of the nation's largest and most experienced distributors of renewable energy products and packaged systems, including solar hot water and solar electric (photovoltaic) systems.  IISS is also a leading supplier of  water heaters and storage tanks, pumps, controls, solar attic fans, skylights and natural day-lighting systems.   Our three Hawaii branches are conveniently located in Honolulu (Oahu), Kahului (Maui) , Kailua-Kona (Big Island) and Lihue (Kauai). IISS represents the leading names in renewable energy and mechanical equipment.