Navien NPE-240A2 Tankless Water Heater vs Rinnai RU199iN Tankless Water Heater

Both are 199,000 BTU indoor condensing tankless units with stainless steel heat exchangers, so raw heating power is a wash. The Navien NPE-240A2 edges ahead on features: a built-in recirculation pump and buffer tank give faster hot water at the tap, it hits 0.95 UEF versus 0.93, and it ships with a field LP conversion kit. The Rinnai RU199iN is the simpler, proven choice with a strong service network and a lower minimum firing rate for small draws. Buy the Navien for near-instant hot water without adding a recirculation loop; buy the Rinnai if you want a straightforward unit with wide installer support.

• Choose the Navien NPE-240A2 if you want built-in recirculation and a buffer tank for faster hot water at the tap, plus slightly higher efficiency and an included LP conversion kit.
• Choose the Rinnai RU199iN if you want a proven, widely serviced condensing unit and don't need an onboard recirculation pump.