Navien NHW-AI Series 199 MBH Indoor Non-Condensing Propane Gas Tankless Water Heater
The NHW-AI series is the indoor version of Navien’s new NHW-A non-condensing tankless lineup. Like the outdoor AE model, it delivers 199,900 BTU/hr input and is designed for high-demand residential and light commercial applications, but in a format built for indoor installation.
🔹 Key Features
-
Non-Condensing Design (UEF ~0.81)
Efficient and reliable, avoids the need for condensate drainage systems common to condensing units. -
ComfortFlow® Built-In Recirculation
Includes internal buffer tank and recirculation pump to reduce “cold water sandwich” effects and deliver hot water faster. -
Stainless Steel Heat Exchanger
Features Navien’s NaviTech™ stainless steel heat exchanger and burner for durability and efficiency. -
Indoor-Specific Design
Forced-draft direct venting system (3″×5″ concentric venting, or 2″/3″ PVC/CPVC/PP options). -
Advanced Safety Systems
-
Air Pressure Sensor (APS): ensures stable combustion.
-
Vent Installation Detector (VID): checks proper vent setup.
-
Water Adjustment Valve (WAV) & mixing valve: maintain consistent outlet temperature.
-
-
Smart Controls
-
Compatible with Navien’s NaviLink™ Wi-Fi remote control system.
-
Digital front panel with diagnostics and precise temperature settings.
-
-
Cascading Capability
Multiple NHW-AI units can be linked to serve very large demand applications.
🔹 Technical Specifications (NHW-199AI-LP)
| Feature | Value |
|---|---|
| Fuel | Propane (LP) or Natural Gas option |
| Input Capacity | 18,000 – 199,900 BTU/hr |
| Max Flow Rate | Up to 9.5 GPM at 35 °F rise |
| UEF | ~0.81 (residential) |
| Temperature Range | 98 °F – 140 °F (up to 180 °F with commercial kit) |
| Gas Connection | ¾″ NPT |
| Water Connection | ¾″ NPT |
| Venting | Concentric 3″×5″, or 2″/3″ PVC/CPVC/PP |
| Dimensions | 26.5″ H × 17.3″ W × 10.3″ D |
| Weight | ~65 lb |
| Warranty (residential) | 15 yr heat exchanger / 5 yr parts / 1 yr labor |
🔹 Applications
-
Whole-home residential hot water supply (multi-bath homes, large tubs, showers, dishwashers, washers).
-
Indoor mechanical rooms, basements, or utility closets where venting options exist.
-
Light commercial use (small restaurants, offices, etc.) when cascaded.
🔹 Why Choose NHW-AI?
-
Ideal if you need an indoor install but want non-condensing simplicity (no drain, lower service complexity).
-
Recirculation and buffer tank built in—less wait for hot water, more comfort.
-
Backed by Navien’s long warranties and stainless steel internals for durability.
Choose options