Absorb ambient heat from the surrounding air to heat water using a compressor and environmentally-friendly R134a refrigerant Self-contained heat pump unit is integrated into the top of the tank Multiple operating modes to maximize efficiency and performance Features ENERGY STAR® qualified Meets NEEA Tier 3 of the Advanced Water Heater Specification 10-Year Limited Tank Warranty, 10-Year Parts Warranty, 1-Year Labor Warranty for Residential applications Dual 4500 watt Copper sheathed “backup” heating elements Advanced electronic control system provides large LCD display for ease of use, precise temperature control and operational status Glass-lined tank with CoreGardTM anode rod protects against corrosion “Environmentally-Friendly” Non-CFC foam insulation Factory-installed temperature & pressure (T&P) relief valve Four Operating Modes: Efficiency (heat pump only) Hybrid (heat pump with electric backup) Electric (electric only) Vacation