The Energy Star Most Efficient designation identifies  the most efficient products among those that qualify for Energy Star in particular product categories.

WaterFurnace International, manufacturer of residential and commercial geothermal and water source heat pumps, announced that its Envision and Synergy3D geothermal heat pumps achieved the Energy Star Most Efficient 2012designation. In its second year, the Energy Star Most Efficient designation is an initiative that identifies and advances the most efficient products among those that qualify for Energy Star in particular product categories.