Some customers - when building, adding on, or simply replacing an old hot water system; want the works - including a new energy saving solar hot water system and an energy effiecient electric hot water heater for backup. It's a GREAT IDEA! Finally you can have a new energy efficient system tailored to your family's size and needs. No more hot water rationing. And with solar's energy savings, this is one home improvement that will pay for itself quickly. By the way, solar makes economic sense even in the northern regions of the US.