Navien owner satisfaction varies significantly by generation. Current NPE-A2 / S2 generation (2018+) gets strong reviews. First-generation NPE-A had a rougher reputation, especially around flow sensor reliability and early NaviLink quality.
What current-gen NPE-A2 owners praise
- Buffer tank solves cold-sandwich — the most-cited NPE-A2 win. Owners coming from Rinnai or Rheem tankless often comment on the difference
- Built-in recirculation pump — clean install, no external Grundfos
- HotButton — owners who use it consistently rate it the best feature
- 15-year warranty — matches Rinnai Sensei
- Modulation range — burner runs smoothly at very low fire levels (washing hands)
- Improved NaviLink — current generation is much better than first-gen
What NCB combi owners praise
- Footprint — single wall-mounted unit replacing boiler + water heater is a real space savings
- Cold-climate performance — NCB-240 and NCB-300 handle the simultaneous demand of multiple bathrooms + heat in cold climates well
- Replacement of old cast-iron boilers — gas bill drops are dramatic (from 70% AFUE to 95% AFUE saves real money)
- Single warranty / single service contact
Common complaints
- First-gen NPE-A flow sensor reliability — well-documented issue on 2014-2018 units. Fixed in NPE-A2
- NaviLink quirks — first-gen NaviLink was unreliable. Current generation much improved but still occasional Wi-Fi drops
- Install mistakes — gas line sizing on 240k models, combi hydronic design. Almost always installer fault, not unit fault
- Customer service hold times — longer than Rinnai (15-30 min vs 5 min). Once you reach a technician, the support is good
- Combi short-cycling — under-designed hydronic systems cycle the combi rapidly. Solvable with proper primary/secondary loop and buffer tank
- Parts availability lag in some regions vs Rinnai
Reliability data
- Field studies of NPE-A2 units installed 2018-2022 show strong heat-exchanger longevity and improved sensor reliability over NPE-A
- NCB combi units installed in cold-climate hydronic applications report good performance over 5-10 year windows
- J.D. Power U.S. Water Heater Satisfaction Study ranks Navien typically #2 in tankless behind Rinnai — close but consistent ranking
Who shouldn't buy Navien
- Homes that don't need recirculation, don't experience cold-sandwich, and have no hydronic heat — pay Rheem prices for a Rheem RTGH and save money
- Homes where the installer isn't Navien-trained and you can't switch installers — install quality dominates outcome
- Very small homes (1-bathroom condo) with light DHW use — a tank water heater is cheaper and adequate
Bottom line
For current-generation Navien (NPE-A2, current NCB / NFC), reviews are strong. Buffer tank is the differentiating feature. First-gen NPE-A has well-known issues that the A2 fixed. For combi boilers, NCB owners consistently report good outcomes when the install is done by a competent hydronics-experienced contractor.