GE describes how the unit works in the GeoSpring Hybrid water heater features:
"A compressor and evaporator are integrated into the electric water heater unit and the evaporator draws in ambient heat from surrounding air using two variable speed fans. Condenser coils wrap the tank all the way to the bottom to transfer this heat into the tank and heat the water.
This innovative process creates the same amount of hot water as a traditional electric water heater, but can reduce water heating expenses up to 62% to save $320* per year. And that could have a dramatic impact on monthly utility bills for years to come!"
On the link describing the water heater’s ability to save energy GE states: “Cut water heating energy usage by up to 62%”. It seems that they arrive at this number by comparing the Energy Factor (EF) of their hybrid heater (2.35) to that of a standard electric water heater (.88). Energy Factor is defined by the DOE as:
"The energy factor (EF) indicates a water heater’s overall energy efficiency based on the amount of hot water produced per unit of fuel consumed over a typical day"
You can buy from national retailers including Lowe's, Sears and Ferguson, your local plumbing supply store (found on the GeoSpring website) or purchase online from the GE Store.