Best Rinnai Natural Gas Tankless Water Heaters: 8 Spec-Based Picks
As an Amazon Associate we earn from qualifying purchases. Links on this page are affiliate links.
Finding the best rinnai natural gas tankless water heaters requires checking the published specs for your home’s flow needs. The Rinnai 7.6 GPM Outdoor Natural Gas Water Heater leads this list because its 9.8 GPM size handles multi-fixture outdoor setups. We compared 8 models using only the specifications listed on their product pages. This approach removes guesswork and focuses on hard data like flow rate, dimensions, and venting type. Use these spec-based picks to decide which unit fits your installation space and hot water demand.
Quick picks
The best fit for you
- You need the highest flow rate for outdoor use Rinnai 7.6 GPM Outdoor Natural Gas Water Heater It delivers 9.8 GPM, the highest output among the outdoor natural gas models listed.
- You want automated recirculation for indoor multi-fixture homes Rinnai 9 GPM Indoor Natural Gas Tankless Water Heater This 9 GPM unit features Smart-Circ technology that learns your usage patterns to schedule hot water delivery.
- You require dedicated commercial-grade capacity for indoor use Rinnai Commercial 9 GPM Indoor Condensing Water Heater It provides 9 GPM of continuous flow specifically designed for commercial indoor facilities with condensing venting.
Our 8 picks
Rinnai 7.6 GPM Outdoor Natural Gas Water Heater
Best for: outdoor natural gas setups needing multi-fixture flow
- Fuel Type
- Natural Gas (what this guide is about)
- Flow Rate
- 9.8 GPM
- BTU
- 199k BTU
- Installation Location
- Outdoor
- Dimensions
- 24.6 x 14.1 x 10.8 in
- Venting Type
- Non-Condensing
View on Amazon: Rinnai 7.6 GPM Outdoor Natural Gas Water Heater
The Rinnai 7.6 GPM Outdoor Natural Gas Tankless Heater mounts outside your home, freeing indoor space without venting ductwork. It delivers up to 7.6 gallons per minute, supplying up to six plumbing fixtures simultaneously. Natural gas powers the non-condensing system, and an onboard LED screen shows diagnostics. This unit suits you if you need whole-home outdoor hot water capacity without installing an indoor exhaust run.
Pros
- Delivers up to 7.6 GPM flow rate to run up to 6 fixtures at once
- Outdoor installation design eliminates indoor venting requirements
- LED screen displays service reminders and diagnostic error codes
- 15-year heat exchanger and 5-year parts residential warranty
Cons
- Outdoor installation only
- WiFi control module and recirculation pump are not included
- Labor warranty drops from 5 years to 1 year if not registered within 90 days
Good fit if
- You need to supply hot water for up to six fixtures simultaneously.
- You prefer an exterior outdoor installation that saves interior floor space.
- You have a natural gas supply line available at the outdoor installation site.
Skip if
- You require an indoor water heater installation.
- You need an internal recirculation pump included out of the box.
- You want built-in WiFi monitoring without buying additional hardware.
Verdict: Rinnai 7.6 GPM Outdoor Natural Gas Tankless Heater delivers robust 7.6 GPM capacity for multi-fixture homes using an exterior-mounted, non-condensing design. It provides dependable natural gas output without occupying interior utility space.
Rinnai 5.3 GPM Outdoor Natural Gas Tankless Heater
Best for: outdoor installations with moderate hot water demands
- Fuel Type
- Natural Gas (what this guide is about)
- Flow Rate
- 5.3 GPM
- Installation Location
- Outdoor
- Dimensions
- 31.2 x 18 x 18 in
- Weight
- 33 pounds
View on Amazon: Rinnai 5.3 GPM Outdoor Natural Gas Tankless Heater
This Rinnai natural gas tankless water heater delivers a flow rate of 5.3 GPM for outdoor installation. At 33 pounds and measuring 31.2 by 18 by 18 inches, it provides continuous hot water for up to four appliances without taking up interior wall space. It suits you if you need an outdoor setup for moderate household water demands.
Pros
- 5.3 GPM flow rate supports up to 4 appliances
- Outdoor installation frees up interior space
- Lightweight unit weighs 33 pounds
- Up to 15-year warranty on the heat exchanger
Cons
- Outdoor installation location only
- Lower 5.3 GPM capacity compared to larger units
- Labor warranty drops to 1 year without 90-day registration
Good fit if
- You have dedicated outdoor mounting space for your water heater.
- You need to supply hot water to up to four appliances at once.
Skip if
- You need an indoor water heater installation.
- You require flow rates higher than 5.3 GPM.
Verdict: Rinnai 5.3 GPM Outdoor Natural Gas Tankless Water Heater delivers dependable exterior water heating for moderate household demands without occupying interior square footage.
Rinnai 7.5 GPM Outdoor Natural Gas Tankless Water Heater
Best for: High-flow outdoor natural gas needs
- Fuel Type
- Natural Gas (what this guide is about)
- Flow Rate
- 7.5 GPM
- Installation Location
- Outdoor
- Dimensions
- 35 x 14.5 x 22 inches
View on Amazon: Rinnai 7.5 GPM Outdoor Natural Gas Tankless Water Heater
The Rinnai RUS75eN is a natural gas tankless water heater designed for outdoor installation. It delivers a flow rate of 7.5 GPM, allowing it to serve up to six appliances simultaneously. The unit measures 35 x 14.5 x 22 inches and features flexible venting options, including PVC or CPVC compatibility. This model suits households needing high-volume hot water in an outdoor setting.
Pros
- 7.5 GPM flow rate for multiple simultaneous uses
- Compact outdoor design fits various spaces
- Flexible venting with PVC/CPVC adaptor support
Cons
- Indoor installation is not supported
- Requires professional installation
- Only 1-year warranty on labor
Good fit if
- You need high flow for multiple bathrooms
- You have outdoor space for installation
- You prefer natural gas fuel
Skip if
- You require indoor installation only
- You want a longer labor warranty
- You need less than 7.5 GPM flow
Verdict: Rinnai RUS75eN 7.5 GPM Outdoor Unit provides robust hot water for large homes with outdoor utility space. It fits buyers who prioritize flow rate and flexible venting over indoor placement convenience.
Rinnai Smart-Circ Outdoor Natural Gas Water Heater
Best for: outdoor installations needing built-in recirculation
- Fuel Type
- Natural Gas (what this guide is about)
- Flow Rate
- 7.9 GPM
- BTU
- 199k BTU
- Installation Location
- Outdoor
- Dimensions
- 24.6 x 14.1 x 10.8 inches
View on Amazon: Rinnai Smart-Circ Outdoor Natural Gas Water Heater
This natural gas unit delivers up to 7.6 GPM, which supplies up to six fixtures at once. It features an integrated recirculation pump with Smart-Circ technology that learns your hot water habits. Designed strictly for outdoor mounting, the non-condensing cabinet measures 24.6 by 14.1 by 10.8 inches. It suits households that want fast hot water delivery without giving up indoor utility space or venting through the roof.
Pros
- Built-in recirculation pump with schedule-learning technology
- Up to 7.6 GPM flow rate supports up to six fixtures simultaneously
- Outdoor installation requires no indoor venting
- Compact cabinet measuring 24.6 by 14.1 by 10.8 inches
Cons
- Outdoor installation only; not rated for indoor mounting
- WiFi monitoring requires separate Controlr module purchase
- Labor warranty drops from five years to one year if not registered within 90 days
Good fit if
- You have exterior wall space and prefer an outdoor natural gas setup.
- You want built-in recirculation without buying an external pump.
- You need up to 7.6 GPM to support multiple fixtures at once.
Skip if
- You require an indoor water heater installation.
- You want built-in WiFi connectivity without purchasing optional accessories.
Verdict: Rinnai 7.6 GPM Outdoor Recirculation Water Heater combines high multi-fixture output with built-in recirculation scheduling in an exterior-mounted design. It is a solid choice when you want fast hot water without routing indoor vent lines.
Rinnai Commercial 9 GPM Indoor Condensing Water Heater
Best for: commercial indoor facilities needing high continuous flow
- Fuel Type
- Natural Gas (what this guide is about)
- Flow Rate
- 9 GPM
- Installation Location
- Indoor
- Dimensions
- 33.9 x 14.8 x 22.1 inches
- Use
- Commercial
- Venting Type
- Condensing
View on Amazon: Rinnai Commercial 9 GPM Indoor Condensing Water Heater
This indoor natural gas tankless water heater is built for commercial demands, delivering up to 9 GPM flow rate using condensing technology. It measures 33.9 inches high and features Circ-Logic recirculation patterns alongside Wi-Fi monitoring capability. If you operate a business requiring reliable hot water delivery and standard commercial warranty coverage—including eight years on the heat exchanger—this indoor model fits your daily high-demand utility setup.
Pros
- Delivers up to 9 GPM flow rate for commercial demands
- Condensing system offers flexible indoor venting options
- Circ-Logic technology supports automated recirculation patterns
- Wi-Fi monitoring enables remote tracking and diagnostics
- Dedicated commercial warranty covers heat exchanger for 8 years
Cons
- Unit requires indoor installation space
- Substantial 72.3-pound weight requires heavy-duty wall mounting
- Commercial labor warranty coverage is limited to 1 year
Good fit if
- You run a business needing up to 9 GPM of continuous hot water.
- You require an indoor natural gas unit with commercial warranty terms.
- You want Wi-Fi monitoring and scheduled recirculation capabilities.
Skip if
- You plan to mount your water heater on an exterior wall.
- You prefer a lightweight unit that requires minimal wall reinforcement.
Verdict: Rinnai Commercial 9 GPM Condensing Gas Water Heater delivers dedicated commercial-grade capacity and 9 GPM flow for indoor utility rooms. It combines efficient condensing performance with smart monitoring to support steady commercial hot water demands.
Rinnai 9 GPM Indoor Condensing Natural Gas Water Heater
Best for: indoor setups needing recirculation without return lines
- Fuel Type
- Natural Gas (what this guide is about)
- Flow Rate
- 9 GPM
- Installation Location
- Indoor
- Dimensions
- 31.3 x 18.5 x 11.4 inches
- Venting Type
- Condensing
- Weight
- 82.5 pounds
View on Amazon: Rinnai 9 GPM Indoor Condensing Natural Gas Water Heater
This Rinnai indoor condensing water heater runs on natural gas and delivers up to 9 GPM flow rate. It features built-in ThermaCirc360 recirculation technology with an integrated pump, timer, and thermal bypass valve, making it practical if your home lacks a dedicated return line. At 82.5 pounds and measuring 31.3 by 18.5 by 11.4 inches, it suits larger households needing high indoor hot-water output without installing separate recirculation hardware.
Pros
- 9 GPM maximum hot water flow rate
- ThermaCirc360 built-in recirculation pump, timer, and thermal bypass valve
- Wi-Fi monitoring capability
- Condensing indoor natural gas operation
Cons
- Discontinued model replaced by the RSC160iN
- Indoor installation only
- Substantial unit weight at 82.5 pounds
Good fit if
- You need up to 9 GPM hot water flow from an indoor natural gas supply.
- You want built-in recirculation hardware without running a dedicated return line.
Skip if
- You prefer an actively manufactured model instead of a discontinued unit.
- You require an outdoor installation location.
Verdict: Rinnai 9 GPM Indoor Condensing Natural Gas Water Heater provides high-volume indoor heating with integrated recirculation for homes lacking dedicated return lines. It remains a capable 9 GPM condensing option, though the manufacturer has designated it as discontinued.
Rinnai 9 GPM Indoor Condensing Natural Gas Heater
Best for: high-demand households running multiple fixtures indoors
- Fuel Type
- Natural Gas (what this guide is about)
- Flow Rate
- 9 GPM
- Installation Location
- Indoor
- Dimensions
- 31.3 x 11.5 x 18.5 inches
- Venting Type
- Condensing
- Weight
- 72.5 pounds
View on Amazon: Rinnai 9 GPM Indoor Condensing Natural Gas Heater
This indoor condensing natural gas water heater delivers up to 9 GPM, which runs up to six appliances at once. Its 0.97 Uniform Energy Factor gives you high thermal efficiency for whole-home use. Built-in Circ-Logic technology supports scheduled or on-demand recirculation when you connect an external pump. It suits larger households that need continuous hot water across multiple fixtures simultaneously.
Pros
- Delivers up to 9 GPM to supply up to 6 appliances at once
- High efficiency with a 0.97 Uniform Energy Factor
- Circ-Logic system supports scheduled or on-demand recirculation
- 15-year residential warranty on the heat exchanger
Cons
- Requires a separate external pump for recirculation
- Controlr Wi-Fi monitoring module is not included
- Configured strictly for indoor installation
Good fit if
- You need high output for up to 6 appliances running at the same time.
- You want an indoor condensing unit with a 0.97 Uniform Energy Factor.
- You plan to connect an external pump for hot water recirculation.
Skip if
- You want built-in Wi-Fi hardware included out of the box.
- You need an outdoor natural gas installation.
- You want an integrated internal recirculation pump.
Verdict: Rinnai 9 GPM Indoor Condensing Natural Gas Water Heater provides high 0.97 UEF efficiency and supports up to six fixtures at once. It gives you dependable high-volume indoor heating if you do not mind adding an external pump for recirculation.
Rinnai 9 GPM Indoor Natural Gas Tankless Water Heater
Best for: multi-fixture homes wanting automated indoor recirculation
- Fuel Type
- Natural Gas (what this guide is about)
- Flow Rate
- Up to 9 GPM
- BTU
- 160,000 BTU/hr
- Installation Location
- Indoor
- Dimensions
- 33.9 x 21.3 x 14.4 inches
- Venting Type
- Condensing
View on Amazon: Rinnai 9 GPM Indoor Natural Gas Tankless Water Heater
This indoor natural gas condensing water heater delivers up to 9 GPM and 160,000 BTU/hr, allowing you to run up to six fixtures at once. Built-in Smart-Circ technology learns your daily hot water habits to schedule pump recirculation for higher efficiency. It fits indoor spaces with multiple venting configurations. You will find it suits households that need multi-point hot water delivery from a compact indoor unit.
Pros
- Up to 9 GPM flow rate supports up to 6 fixtures at once
- Smart-Circ technology learns usage patterns to automate recirculation
- High 160,000 BTU/hr natural gas heating input
- ENERGY STAR qualified condensing operation
Cons
- Controlr WiFi module is not included
- Indoor installation only
- Professional technician installation is recommended
Good fit if
- You need to supply hot water to up to six fixtures at the same time.
- You want an indoor condensing natural gas unit with automated recirculation scheduling.
- You require flexible venting options for an indoor installation.
Skip if
- You need an outdoor tankless water heater.
- You require WiFi connectivity without buying an add-on module.
Verdict: Rinnai Smart-Circ 9 GPM Condensing Tankless Heater provides 160,000 BTU/hr and automated recirculation learning for indoor natural gas systems. It is an effective option if you need multi-fixture indoor performance and built-in circulation scheduling.
Specifications side by side
| Spec | Rinnai 7.6 GPM Outdoor Natural Gas Water Heater | Rinnai 5.3 GPM Outdoor Natural Gas Tankless Heater | Rinnai 7.5 GPM Outdoor Natural Gas Tankless Water Heater | Rinnai Smart-Circ Outdoor Natural Gas Water Heater | Rinnai Commercial 9 GPM Indoor Condensing Water Heater | Rinnai 9 GPM Indoor Condensing Natural Gas Water Heater | Rinnai 9 GPM Indoor Condensing Natural Gas Heater | Rinnai 9 GPM Indoor Natural Gas Tankless Water Heater |
|---|---|---|---|---|---|---|---|---|
| Fuel Type | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas |
| Flow Rate | 9.8 GPM | 5.3 GPM | 7.5 GPM | 7.9 GPM | 9 GPM | 9 GPM | 9 GPM | Up to 9 GPM |
| BTU | 199k BTU | not specified | not specified | 199k BTU | not specified | not specified | not specified | 160,000 BTU/hr |
| Installation Location | Outdoor | Outdoor | Outdoor | Outdoor | Indoor | Indoor | Indoor | Indoor |
| Dimensions | 24.6 x 14.1 x 10.8 in | 31.2 x 18 x 18 in | 35 x 14.5 x 22 inches | 24.6 x 14.1 x 10.8 inches | 33.9 x 14.8 x 22.1 inches | 31.3 x 18.5 x 11.4 inches | 31.3 x 11.5 x 18.5 inches | 33.9 x 21.3 x 14.4 inches |
| Use | not specified | not specified | not specified | not specified | Commercial | not specified | not specified | not specified |
| Venting Type | Non-Condensing | not specified | not specified | not specified | Condensing | Condensing | Condensing | Condensing |
| Weight | 53.3 pounds | 33 pounds | not specified | not specified | 72.3 pounds | 82.5 pounds | 72.5 pounds | 66 pounds |
| Size | 9.8 GPM | 5.3 GPM | 7.5 GPM | 7.9 GPM | not specified | 9 GPM | 9 GPM | not specified |
| Color | Silver | Euro White | Outdoor Installation | Silver | CU160in - Natural Gas/9 GPM | Silver | Silver | Gray |
| Model | REU-VE2737WD-US-N | V53DeN | RUS75eN | REU-VEP2737WD-US-N | CU160iN | RUR160iN | RU160in | RSC160iN |
If you route a supply line outdoors, evaluate heat output data for the best natural gas patio heaters.
How to Choose the Right Rinnai Gas Heater
-
Match Flow to Fixture Count
Your daily hot water needs dictate the required gallons per minute. If you run multiple showers or appliances simultaneously, you need higher flow. The Rinnai 7.6 GPM Outdoor model offers a 9.8 GPM capacity, making it suitable for large homes with heavy demand. For moderate usage, the 5.3 GPM Outdoor unit provides sufficient output without excess capacity. Check the size spec in the data to ensure the unit meets your peak usage requirements.
-
Select Installation Location
Decide between indoor and outdoor placement based on your available space. Outdoor models like the REU-VE2737WD-US-N are designed for exterior mounting, saving interior utility room space. Indoor units, such as the CU160iN, fit inside closets or mechanical rooms. Verify the installation location attribute for each model. Outdoor units often require different venting considerations compared to indoor condensing systems, so plan your layout accordingly before purchasing.
-
Check Venting Type
Venting requirements vary significantly between non-condensing and condensing models. Non-condensing units, like the outdoor REU-VE2737WD-US-N, use standard venting materials. Condensing indoor units, such as the RUR160iN, produce acidic exhaust that requires specific PVC or CPVC piping. Ensure your existing venting infrastructure matches the unit type. Installing a condensing unit with improper venting can lead to corrosion or safety issues, so verify the venting type attribute carefully.
-
Consider Recirculation Features
Built-in recirculation reduces wait time for hot water. The Rinnai Smart-Circ Outdoor model includes scheduling features to manage water temperature efficiently. The indoor RUR160iN also offers integrated recirculation for homes without dedicated return lines. If you prefer manual control, the RU160in requires an external pump. Check the attributes for recirculation capabilities. This feature impacts convenience and energy use, so choose based on your household’s hot water habits.
-
Verify Commercial vs Residential Use
Some units are rated for commercial applications, offering higher durability and flow. The CU160iN is designated for commercial indoor facilities, providing 9 GPM steady flow. Residential models like the RUS75eN are optimized for home use. Ensure the use attribute matches your property type. Commercial units may have different warranty terms or installation requirements. Selecting the correct category ensures the unit meets your specific operational demands and regulatory standards.
Frequently asked questions
Which Rinnai natural gas tankless water heater has the highest flow rate?
The Rinnai 7.6 GPM Outdoor Natural Gas Water Heater offers the highest flow rate at 9.8 GPM. This capacity supports multi-fixture outdoor setups efficiently. It uses a non-condensing design for exterior mounting. This model provides robust output for homes needing simultaneous hot water access outside.
Does the Rinnai 9 GPM Indoor Condensing model include built-in recirculation?
The Rinnai Smart-Circ 9 GPM Condensing Tankless Heater includes automated recirculation learning. It schedules water circulation based on your usage patterns. Other 9 GPM indoor models, like the RUR160iN, do not list built-in recirculation. You may need an external pump for those units.
What is the difference between condensing and non-condensing Rinnai gas heaters?
Condensing models like the CU160iN and RUR160iN are designed for indoor installation. They use condensing venting for efficiency. Non-condensing models, such as the REU-VE2737WD-US-N, are built for outdoor use. This distinction determines where you can safely mount the unit in your home.
Which Rinnai natural gas heater is best for moderate outdoor use?
The Rinnai 5.3 GPM Outdoor Natural Gas Tankless Heater is ideal for moderate demands. It delivers 5.3 GPM for outdoor installations. This Euro White unit weighs 33 pounds. It provides dependable heating without occupying interior space for smaller households.
How many fixtures can the Rinnai 9 GPM Indoor Condensing model support?
The Rinnai 9 GPM Indoor Condensing Natural Gas Heater supports up to six fixtures simultaneously. It delivers high-volume heating for large households. The RU160in model achieves 0.97 UEF efficiency. This capacity ensures consistent hot water for multiple bathrooms and appliances.
Are all listed Rinnai natural gas models outdoor rated?
No, several models are rated for indoor installation. The CU160iN, RUR160iN, RU160in, and RSC160iN are designed for indoor use. They feature condensing venting systems. Outdoor models like the REU-VE2737WD-US-N and V53DeN are built for exterior mounting and weather resistance.
What is the weight of the heaviest Rinnai natural gas water heater?
The Rinnai 9 GPM Indoor Condensing Natural Gas Heater (RUR160iN) is the heaviest at 82.5 pounds. It measures 18.5 inches wide and 31.3 inches high. This weight reflects its commercial-grade indoor construction. Ensure your installation area can support this load.
Which Rinnai model offers the best premium outdoor recirculation features?
The Rinnai Smart-Circ Outdoor Natural Gas Water Heater offers premium recirculation. It combines 7.9 GPM output with built-in scheduling. This Silver unit measures 14.1 inches wide. It provides fast hot water without routing indoor vent lines, making it a top outdoor choice.