Rinnai RX199iN Condensing Tankless Water Heater Review: Smart Power, Endless Hot Water, and Flexible Installation
Modern households demand more from their water heating systems than ever before. Multiple bathrooms, high-flow showers, large tubs, dishwashers, and washing machines often operate at the same time. Traditional tank water heaters struggle to keep up, leading to cold-water interruptions, wasted energy, and frustration. The Rinnai RX199iN Condensing Smart Sense Tankless Water Heater is designed to eliminate these problems by delivering continuous hot water, high efficiency, and exceptional installation flexibility.
This in-depth review explores how the RX199iN performs, what sets it apart from other tankless water heaters, and why it has become a strong choice for homeowners looking for a premium, whole-house solution. From its impressive 199,000 BTU output to its Smart Sense gas control and indoor or outdoor installation capability, this model represents Rinnai’s advanced approach to tankless water heating.
Product Overview
The Rinnai RX199iN is a high-capacity condensing tankless water heater engineered for whole-house use. It supports both natural gas and propane, operates indoors or outdoors, and delivers up to 11.1 gallons per minute of hot water. This level of performance allows it to supply multiple fixtures simultaneously without temperature drops.
Unlike traditional storage tanks that heat and reheat water all day, this unit heats water only when needed. The result is endless hot water combined with impressive energy efficiency, making it ideal for medium to large households.
Key Features at a Glance
- Up to 11.1 GPM hot water output
- 199,000 BTU heating capacity
- Condensing technology with high efficiency
- Compatible with natural gas or propane
- Indoor or outdoor installation capability
- Compact, suitcase-sized design
- Smart Sense gas control system
- UEF rating up to 0.98
- Quick Flush maintenance feature
- Expandable smart control options
These features position the RX199iN as a premium solution for homeowners seeking performance, efficiency, and flexibility.
Product Specifications Table
| Feature | Specification |
|---|---|
| Product Name | Rinnai RX199iN Condensing Tankless Water Heater |
| Fuel Type | Natural Gas or Propane |
| Maximum Flow Rate | Up to 11.1 GPM |
| Heating Capacity | 199,000 BTU |
| Energy Efficiency | UEF up to 0.98 |
| Installation Location | Indoor or Outdoor |
| Venting System | Versa Vent (RX-OVC cap required for outdoor) |
| Design Type | Condensing tankless |
| Size | Compact, suitcase-sized |
| Control Interface | Built-in digital interface |
| Smart Control | WiFi capable with Controlr module (sold separately) |
| Maintenance Feature | Quick Flush |
| Recommended Installation | Professional |
Endless Hot Water for High-Demand Homes
One of the biggest advantages of the Rinnai RX199iN Tankless Water Heater is its ability to deliver hot water continuously. With a maximum flow rate of up to 11.1 GPM, it can support up to seven fixtures running at the same time.
Real-World Usage Scenarios
- Two showers running simultaneously
- A shower, dishwasher, and washing machine at once
- Multiple bathroom sinks in use while filling a tub
The heater maintains consistent water temperature even during peak demand. This makes it an excellent choice for families, multi-bathroom homes, and households with high daily hot water usage.
Condensing Technology and High Energy Efficiency
The RX199iN uses advanced condensing technology to maximize efficiency. Unlike non-condensing tankless water heaters that allow heat to escape through exhaust gases, this model captures and reuses that heat to warm incoming water.
Benefits of Condensing Design
- Higher energy efficiency compared to standard tankless models
- Lower fuel consumption over time
- Reduced exhaust temperature for safer venting
- Improved long-term operating cost savings
With a UEF rating of up to 0.98, this unit ranks among the most efficient gas tankless water heaters available for residential use.
Smart Sense Gas Control System
The Smart Sense gas control system allows the RX199iN to automatically adapt to either natural gas or propane without requiring separate models. This adds significant flexibility, especially for homeowners who may switch fuel types or live in areas where fuel availability varies.
Advantages of Smart Sense Technology
- Simplified model selection
- Automatic gas type detection
- Optimized combustion for efficiency and safety
- Reduced risk of improper configuration
This intelligent system contributes to both performance reliability and ease of installation.
Indoor or Outdoor Installation Flexibility
Unlike many tankless water heaters that are limited to indoor installations, the Rinnai RX199iN can be installed either indoors or outdoors. This flexibility allows homeowners to choose the most convenient location based on space availability and climate.
Indoor Installation Benefits
- Protected from weather conditions
- Ideal for basements, utility rooms, or garages
- Works seamlessly with Versa Vent systems
Outdoor Installation Benefits
- Saves indoor space
- Simplifies venting requirements
- Ideal for warmer climates
For outdoor installations, the RX-OVC vent cap is required to ensure safe operation.
Compact Design with Powerful Output
Despite its high performance, the RX199iN maintains a compact, suitcase-sized design. This makes it easier to install in tight spaces compared to bulky storage tanks.
Design Highlights
- Wall-mountable form factor
- Clean, modern appearance
- Efficient internal layout
- Minimal footprint
This combination of compact size and high output allows homeowners to upgrade performance without sacrificing space.
User Interface and Smart Control Options
The unit features an intuitive digital interface that provides real-time system information and simplifies temperature adjustments. For users seeking advanced control, the RX199iN is compatible with the optional Controlr module, which enables WiFi connectivity.
Smart Control Capabilities
- Remote temperature adjustment
- System monitoring
- Maintenance alerts
- Integration with mobile devices
While the Controlr module is not included, it expands the functionality of the heater for tech-savvy users.
Quick Flush Feature for Easy Maintenance
Routine maintenance is essential for maintaining efficiency and extending the lifespan of any tankless water heater. The Quick Flush feature built into the RX199iN simplifies the flushing process, reducing the time and effort required.
Why Quick Flush Matters
- Encourages regular maintenance
- Reduces mineral buildup
- Helps maintain peak efficiency
- Extends system longevity
This feature is particularly valuable in areas with hard water, where mineral scale can accumulate more quickly.
Professional Installation Considerations
Rinnai strongly recommends professional installation for the RX199iN. Given the unit’s high BTU rating, gas connections, and venting requirements, professional installation ensures safety, optimal performance, and compliance with local codes.
Why Professional Installation Is Important
- Proper gas line sizing
- Correct venting configuration
- Accurate system setup
- Warranty protection
A qualified technician can also help determine whether the RX199iN is the right size for your household based on local groundwater temperature and usage patterns.
Performance Across Different Climates
The RX199iN is designed to perform reliably across a wide range of climates. Its high heating capacity ensures strong performance even in colder regions where incoming groundwater temperatures are lower.
Cold Climate Performance
- Maintains high output with low inlet temperatures
- Supports multiple fixtures simultaneously
- Reduces performance drop common in undersized units
This makes it suitable for both warm and cold regions when properly sized.
Comparison With Traditional Tank Water Heaters
Tankless vs Tank Water Heaters
| Feature | RX199iN Tankless | Traditional Tank |
|---|---|---|
| Hot Water Supply | Endless | Limited by tank size |
| Energy Efficiency | Very high | Moderate |
| Space Requirement | Compact | Large |
| Lifespan | Longer | Shorter |
| Standby Heat Loss | None | Yes |
The RX199iN eliminates standby heat loss and provides continuous hot water, offering clear advantages over traditional tank systems.
Comparison With Lower-Capacity Tankless Models
Lower-capacity tankless water heaters may struggle to support multiple fixtures at once. The RX199iN’s high GPM rating ensures consistent performance even during peak demand.
| Feature | RX199iN | Lower-Capacity Model |
|---|---|---|
| Maximum GPM | Up to 11.1 | 6–8 GPM |
| Fixture Support | Up to 7 | 3–4 |
| Whole-House Use | Yes | Limited |
| BTU Output | 199,000 | Lower |
This makes the RX199iN a better fit for larger households or homes with higher water usage.
Reliability and Brand Reputation
Rinnai is widely recognized for its expertise in tankless water heating technology. The RX199iN reflects the brand’s focus on innovation, durability, and long-term reliability.
Key factors contributing to reliability include:
- High-quality internal components
- Advanced safety systems
- Proven condensing technology
- Comprehensive support resources
These elements help ensure dependable performance over many years of use.
Who Should Choose the Rinnai RX199iN
The Rinnai RX199iN Condensing Tankless Water Heater is best suited for:
- Medium to large households
- Homes with multiple bathrooms
- Families with high simultaneous water demand
- Homeowners seeking energy efficiency
- Those wanting indoor or outdoor installation flexibility
It may be more than necessary for very small households with minimal hot water usage, but for demanding applications, it offers excellent value and performance.
Final Evaluation
The Rinnai RX199iN Tankless Water Heater stands out as a powerful, efficient, and flexible whole-house hot water solution. Its ability to deliver up to 11.1 GPM, combined with condensing efficiency, Smart Sense gas control, and compact design, makes it a strong contender in the premium tankless category.
While professional installation is recommended, the long-term benefits in comfort, efficiency, and reliability make this investment worthwhile for many homeowners. For those who want endless hot water without sacrificing efficiency or space, the RX199iN delivers on its promise.