- 80% Thermal Efficiency
- Indoor Only
When you need a smart, simple replacement for an old-style, traditional tank, the new Demand Duo R-Series Commercial Hybrid Water Heating System is the ideal choice. The R-Series vents into existing 6" B Vent, so you save installation time and costs. What’s more, you increase customer satisfaction with a system that delivers reliable performance, longer service life, and a lower total cost of ownership.