Choosing the right Rinnai tankless water heater ensures you have an endless supply of hot water while saving on energy costs. With various models available, it’s essential to select one that fits your household’s specific needs.
Rinnai Tankless Water Heater Comparison
| Product | Best for | Flow Rate (GPM) | Energy Factor | Type | Warranty | Price |
|---|---|---|---|---|---|---|
| Rinnai RE199iP Propane Tankless Water Heater | Best Overall | 7.6 | — | Propane | 15-year heat exchanger, 5-year parts and labor | Check price |
| Rinnai RE199eN Natural Gas Tankless Water Heater | Best for Outdoor Use | 7.6 | — | Natural Gas | 15-year heat exchanger, 5-year parts and labor | Check price |
| Rinnai RE180eN Natural Gas Tankless Water Heater | Best for Mid-Sized Homes | 6.9 | — | Natural Gas | 15-year heat exchanger, 5-year parts and labor | Check price |
| Rinnai RE140iN Natural Gas Tankless Water Heater | Best Compact Model | 5.3 | — | Natural Gas | 15-year heat exchanger, 5-year parts and labor | Check price |
| Rinnai RE140eN Natural Gas Tankless Water Heater | Best Budget Option | 5.3 | — | Natural Gas | 15-year heat exchanger, 5-year parts and labor | Check price |
Top Picks for Rinnai Tankless Water Heaters
Rinnai RE199iP Propane Tankless Water Heater
- Flow Rate (GPM)7.6
- TypePropane
- Warranty15-year heat exchanger, 5-year parts and labor
- High flow rate of 7.6 GPM
- Energy-saving smart design
- Clear LED display for diagnostics
- Long 15-year heat exchanger warranty
- Requires professional installation
- No included WiFi control module
Rinnai RE199eN Natural Gas Tankless Water Heater
- Flow Rate (GPM)7.6
- TypeNatural Gas
- Warranty15-year heat exchanger, 5-year parts and labor
- 7.6 GPM flow rate
- Outdoor installation ready
- Energy-efficient smart heating
- LED service and error display
- Professional installation required
- No included WiFi control
Rinnai RE180eN Natural Gas Tankless Water Heater
- Flow Rate (GPM)6.9
- TypeNatural Gas
- Warranty15-year heat exchanger, 5-year parts and labor
- 6.9 GPM flow rate
- Compact outdoor design
- Energy-saving operation
- Diagnostic LED screen
- Lower flow than top models
- No WiFi control included
Rinnai RE140iN Natural Gas Tankless Water Heater
- Flow Rate (GPM)5.3
- TypeNatural Gas
- Warranty15-year heat exchanger, 5-year parts and labor
- Compact size
- 5.3 GPM flow rate
- Energy-efficient heating
- LED error codes and service reminders
- Lower flow rate limits simultaneous use
- No WiFi control included
Rinnai RE140eN Natural Gas Tankless Water Heater
- Flow Rate (GPM)5.3
- TypeNatural Gas
- Warranty15-year heat exchanger, 5-year parts and labor
- Affordable natural gas model
- 5.3 GPM flow rate
- Energy-saving smart design
- LED display for maintenance
- Limited flow rate
- No WiFi control included
How to Choose the Best Rinnai Tankless Water Heater
Rinnai stands out for its reliable engineering, energy efficiency, and extensive model range. Their tankless water heaters deliver hot water on demand, reduce standby heat loss, and offer long lifespans with routine maintenance. For a large household, the Rinnai RE199iP is a top pick. It supports multiple simultaneous fixtures with a flow rate of 11 gallons per minute (GPM), enough for several showers and appliances running at once.
Choosing between condensing and non-condensing models depends on your budget and efficiency goals. Condensing units capture extra heat from exhaust gases, reaching efficiency ratings above 90%, which lowers fuel costs. Non-condensing models, like the RE199iP, typically have efficiency around 82%, but cost less upfront and are simpler to install.
Installation requires checking fuel type compatibility—propane or natural gas—and ensuring proper venting and clearance space. Rinnai’s compact designs fit easily in utility rooms or closets but need access for servicing. Their warranty covers parts and labor for 5 to 12 years depending on the model and usage type, backed by responsive customer support.
| Model | Fuel Type | Max Flow Rate (GPM) | Efficiency (%) | Warranty (Years) |
|---|---|---|---|---|
| RE199iP | Propane | 11 | 82 | 12 |
| RE199eN | Natural Gas | 11 | 82 | 12 |
| RE180eN | Natural Gas | 9.8 | 82 | 12 |
| RE140iN | Natural Gas | 7.5 | 82 | 12 |
| RE140eN | Natural Gas | 7.5 | 82 | 12 |
Sizing and Heat Output for Your Home
Sizing a tankless water heater starts with calculating your household’s peak hot water demand in gallons per minute (GPM). Add the flow rates of all fixtures likely to run at once: showers (1.5–2.5 GPM), faucets (0.5 GPM), and appliances like dishwashers (1.5 GPM). For example, two showers and a faucet used simultaneously total about 5.5 GPM.
Consider peak usage times carefully. Morning routines or evenings when multiple fixtures run together require enough capacity to avoid temperature drops. Oversizing slightly ensures consistent hot water without excessive cycling, which can reduce the heater’s lifespan.
Temperature rise is the difference between the groundwater temperature and your desired output temperature, usually 120°F. Groundwater temperatures vary by region, from 40°F in colder areas to 70°F in warmer ones. The heater must provide enough BTUs to raise the water temperature at your peak flow rate.
- Calculate total GPMAdd flow rates of fixtures used simultaneously to find total demand.
- Determine temperature riseSubtract groundwater temperature from desired hot water temperature (typically 120°F).
- Match heater capacityChoose a model with a BTU rating that covers the required temperature rise at your total GPM.
The Rinnai RE199iP suits homes needing up to 11 GPM and temperature rises up to 70°F, covering most large households. Smaller models like the RE140iN fit homes with lower demand and smaller temperature rises. Correct sizing prevents running costs from rising due to inefficient cycling or insufficient hot water.
For more sizing details and options for smaller homes, see best tankless water heater for small home.
Understanding Running Costs of Tankless Water Heaters
A Rinnai tankless water heater uses gas or electricity only when you run hot water, unlike traditional models that keep a tank heated all day. This on-demand operation cuts energy waste and lowers monthly costs.
To calculate running costs, multiply the heater’s power use by your hot water hours and local energy rate. For example, a 199,000 BTU per hour gas model running an hour daily at $1.20 per therm costs about $1.20 per day or $36 monthly. Electric models draw watts per minute of use, typically less than 5 kW, so costs depend on your water use and electricity price.
Energy efficiency varies with fuel type, model design, and water temperature rise. Condensing models recover heat from exhaust gases, reaching up to 95% efficiency. Non-condensing models like most Rinnai units run around 80-85%. Lower temperature rises and shorter hot water runs improve efficiency.
Tankless systems avoid standby losses common in tank heaters, which keep water hot 24/7. This can save 10% to 30% on energy bills depending on household use. However, upfront costs and installation complexity are higher.
| Appliance | Watts | Per hour | Per day (8 h) | Per month (30 days) |
|---|---|---|---|---|
| Electric tankless (5,000 W) | 5,000 W | 85¢ | $6.80 | $204.00 |
Safety Considerations and Certifications
Rinnai tankless water heaters carry certifications such as UL and CSA, confirming compliance with US and Canadian safety standards. These labels ensure the units meet electrical and gas safety requirements.
| Certification | Purpose |
|---|---|
| UL | Safety of electrical components and gas connections |
| CSA | Compliance with Canadian safety and performance standards |
Professional installation is critical. Incorrect gas line sizing, venting, or electrical wiring can cause leaks, carbon monoxide buildup, or fire hazards. Always hire a licensed plumber or HVAC technician familiar with tankless systems.
Look for safety features such as overheat protection, flame failure detection, and freeze protection. These prevent damage to the unit and hazards to your home.
Review warranty terms carefully. Rinnai’s warranty covers defects but may exclude damage from improper installation or lack of maintenance. Following safety and installation guidelines protects your investment.
Unique Features of Rinnai Tankless Water Heaters
Rinnai tankless water heaters stand out for their blend of smart technology, compact design, and connectivity. Their unique Smart-Circ technology reduces water waste by recirculating hot water efficiently, cutting wait times and lowering water costs. This system activates on demand or by timer, so you get hot water faster without running the tap continuously.
| Feature | Benefit |
|---|---|
| Smart-Circ Technology | Recirculates water to reduce wait time and conserve water |
| Compact Design | Fits tight spaces for easier installation in closets or small utility rooms |
| Smart Home Integration | Works with apps and voice assistants for remote control and monitoring |
Rinnai models are smaller than many competitors, with slim profiles that simplify installation even in confined spaces. This compactness means fewer remodeling costs and more placement options. Their designs also prioritize quiet operation and durability, making them suitable for indoor and outdoor setups.
Smart home integration lets you control hot water temperature and set schedules from a smartphone or compatible home system. This feature adds convenience and can improve energy management by heating water only when needed.
Frequently Asked Questions
What distinguishes Rinnai as a premier tankless water heater?
Which Rinnai model is optimal for a large household?
Are Rinnai condensing units superior to non-condensing models?
What is the significance of Circ-Logic technology in Rinnai heaters?
How do I install a Rinnai tankless water heater safely?
What maintenance is required for Rinnai tankless water heaters?
If that sounds like your room, read up on tankless water heaters with backup next.
For the detail, see our notes on convenient water heating.
