The CopperHeart Integral Collector Storage System (ICS):

Combines thermal collection and storage in a single unit. The CopperHeart is designed to meet the international demand for a simple, durable and inexpensive domestic water heating system. The CopperHeart typically serves as a solar preheater to an existing electric or gas water heater, but may be used as the primary water heater in certain climates. ICS units are excellent choices for residential new construction in the U.S. Sunbelt or other mild climates that do not experience hard freeze conditions.