Best for Quick Replacements

Demand Duo® is great for emergency replacement and high-capacity needs because it has the storage capacity of a tank paired with the energy efficiency and longer life of a tankless.

Demand Duo® Benefits

How it Works

Greater Capacity and Lifespan

The Rinnai Demand Duo® pairs a durable 119-gallon tank with a Rinnai CU199 tankless unit.

  • A direct replacement with connections similar to most high-efficiency tanks.
  • Simple to install and keeps pace with an establishment’s hot water needs.

Demand Duo® Solutions

Demand Duo®

Bringing a multitude of installation options as well as an upgraded recovery pump for improved tank recovery time.

  • Choice of multiple tankless and tank options
  • Preassembled electric and gas connections
  • Set building recirculation and temperature setpoint with the Digital Controller

Demand Duo®

Our newest line of commercial hybrid water heaters brings the performance, versatility and reliability from Rinnai. And it's backed by the industry's best warranty.

  • No new vent runs or structure penetrations required
  • Longer lifespan with no thermal stress on tank
  • Easily connect to existing 6" B-Vent
Demand Duo R-Series 100

Demand Duo®

Non-Condensing Hybrid

View Models

Demand Duo® 2V

Combining the redundancy and performance of our tankless rack systems with the hybrid technology of Demand Duo®.

  • Built-in redundancy for reliable hot water
  • Cutting-edge technology that’s easy to maintain
  • ASME certified option available

Get a custom solution and a professional installation for your business from our Rinnai experts.