Rinnai Sensei RX — Built-in Recirculation Flagship

Sensei RX is Rinnai's top-tier residential tankless. Same condensing chassis as the standard Sensei (RU) series, plus an integrated recirculation pump and dedicated return-line port. The "RX" line is purpose-built for homes that want hot-water recirculation done right.

What you get over standard Sensei

• Built-in recirculation pump — lives inside the cabinet. No external Grundfos or Taco
• Dedicated return-line port — plumbed connection for the return loop. Cleaner install than an external pump
• Circ-Logic firmware — adaptive recirculation that learns your usage pattern. See Circ-Logic hub
• Same 15-year heat exchanger warranty, 5-year parts, 1-year labor
• Same ControlR Wi-Fi built-in

The Sensei RX lineup

When to choose Sensei RX over standard Sensei

• You have or plan to install a hot-water recirculation loop (return line)
• You're tired of waiting 30-90 seconds for hot water at distant fixtures
• You want the cleanest install — no external pump, no extra electrical, no separate timer
• You value the Circ-Logic learning mode over manual schedules

When to stay on standard Sensei

• You don't have a return line and aren't going to add one (RX without a return line is wasted money — the pump can't do anything useful)
• You'd rather spend the $300-500 difference on other house projects
• You already have a perfectly good Grundfos recirculation pump under the kitchen sink

Cost

• RX130iN: $1,800-2,050
• RX180iN: $1,950-2,250
• RX199iN: $2,099-2,399

Install requirements

Same as Sensei plus:

• Dedicated ¾" return line from the farthest fixture to the unit (with check valve and isolation valves)
• Return line typically requires retrofit plumbing if not new construction — budget $1,500-3,000 extra labor

Bottom line

If you've decided to install a recirculation loop, Sensei RX is the right answer — purpose-built integration, mature firmware, no external mess. See our recirculation hub for the full architecture comparison.