Dual-Fuel Hybrid Residential Water Heater – Technical and Laboratory Evaluation

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The Northwest Energy Efficiency Alliance (NEEA) co-funded a laboratory study conducted by GTI Energy to evaluate the Navien 120V Residential Dual-Fuel Water Heater. This novel product features multiple on-board operating modes and integrates an industry- first 120-Volt (V) electric heat pump paired with either a 40- or 60-kBTU/h natural gas condensing backup burner. The research characterized technical performance and energy consumption across a variety of operating conditions. The results convey robustness, energy efficiency and overall value proposition. Testing validated initial claims by the manufacturer, yielding results of:

• 40 kBTU/h model: FHR of 81.67 gallons; UEF of 3.86 (E-saver mode) and 0.88 (Gas-only mode)
• 60 kBTU/h model: FHR of 98.18 gallons; UEF of 3.79 (E-saver mode) and 0.93 (Gas-only mode)

These findings support the potential for residential consumers to reduce energy use and easily upgrade their existing natural gas water heater to a dual-fuel system without incurring costly upgrades.