6 Best Alternatives to the Noritz NR98-OD NG Outdoor Tankless (2026)
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If you want to replace or compare your current heater, finding the right noritz nr98 od ng outdoor tankless alternatives helps you match your home demands. The Noritz NR98-OD NG delivers strong performance with a 199,000 BTU heating capacity and a 7.5 GPM flow rate. Its low 0.05 GPM activation flow rate ensures hot water even during low demand, while the outdoor configuration eliminates indoor venting requirements entirely. It also features an 84 percent thermal efficiency rating and an onboard computer system for self-diagnostics.
You might still prefer a different unit if your household requires higher water volume, such as 8.5 or 9.5 GPM, or features like built-in WiFi monitoring. Other homeowners may need a more compact casing or prefer another brand like Rheem or Rinnai. This guide highlights 6 alternatives chosen because their specifications directly overlap with the Noritz NR98-OD NG. Every option shares exterior mounting and natural gas fuel while providing distinct flow rates, dimensions, and hardware configurations for 2026.
Our top pick: Noritz 7.5 GPM Outdoor Natural Gas Water Heater.
Comparing Noritz NR98-OD NG Alternatives
Rinnai 7.5 GPM Outdoor Natural Gas Tankless Water Heater
The Rinnai RUS75eN matches the 7.5 GPM outdoor natural gas delivery of the Noritz NR98-OD NG. It gives you clear exterior measurements of 14.5 inches wide, 22 inches long, and 35 inches high, helping you verify outdoor wall space before installation. However, you give up the Noritz unit's published 199,000 BTU rating, 84% thermal efficiency, and 0.05 GPM activation flow rate. The Rinnai also omits the self-diagnostic onboard computer system detailed on the Noritz. You should choose this Rinnai model if you want an outdoor natural gas heater with identical 7.5 GPM capacity in Rinnai's exterior dimensions.
Noritz 9.8 GPM Natural Gas Tankless Water Heater
The Noritz NR98SVNG shares natural gas outdoor support and beige styling with the original NR98-OD NG, while adding the ability to link two units together. It provides explicit physical specifications, measuring 23.6 inches high, 13.8 inches long, and 10.6 inches wide at 54 pounds. What you give up compared to the original is the stated 0.05 GPM low-flow activation rate and the 84% thermal efficiency rating. Its attribute flow rate remains at 7.5 GPM, though its size designation notes 9.375 inches. Choose the NR98SVNG over the NR98-OD NG if you require a multi-unit linked setup and need verified chassis dimensions for your exterior wall mounting.
Ranein 8.5 GPM Outdoor Natural Gas Water Heater
The Ranein RHO19K-NG provides a lighter 44-pound gray chassis measuring 24.3 inches high by 15.1 inches wide and long for outdoor natural gas placement. It operates at 190,000 BTU, slightly below the 199,000 BTU maximum of the Noritz NR98-OD NG. You give up the Noritz unit's consistent 7.5 GPM flow rate, as the Ranein lists an attribute flow rate of 5.0 GPM despite its 8.5 GPM model sizing. You also lose the 0.05 GPM activation threshold, onboard computer diagnostics, and 84% thermal efficiency. Choose the Ranein if your outdoor installation is below 2,000 feet and you prefer a lighter gray cabinet over the original beige Noritz.
Rinnai 7.6 GPM Outdoor Natural Gas Water Heater
The Rinnai REU-VE2737WD-US-N offers a 7.6 GPM rated flow rate, edging slightly past the 7.5 GPM rate of the Noritz NR98-OD NG. Built in silver at 53.3 pounds, it explicitly operates as a non-condensing natural gas outdoor unit measuring 24.6 inches high, 14.1 inches wide, and 10.8 inches long. By choosing this Rinnai, you give up the 199,000 BTU rating, 84% thermal efficiency, and sensitive 0.05 GPM activation flow rate published for the Noritz. It also omits the self-diagnostic onboard computer system found on the NR98-OD NG. Select this Rinnai if you need a non-condensing outdoor natural gas heater in a silver exterior finish.
APUS 190,000 BTU Outdoor Natural Gas Water Heater
The APUS AP-AWH-W26NG provides an ultra-compact exterior profile, measuring just 6.54 inches wide, 6.54 inches long, and 22.5 inches high while weighing 42.5 pounds. Its 190,000 BTU heating capacity approaches the 199,000 BTU output of the Noritz NR98-OD NG. However, it gives up the Noritz unit's established 7.5 GPM flow rate attribute, 84% thermal efficiency spec, and ultra-low 0.05 GPM activation rate. The APUS also lacks the self-diagnostic onboard computer system specified on the Noritz. Choose the APUS if your outdoor natural gas installation has very narrow mounting clearances and demands a compact, lightweight gray housing.
Rheem RTG 9.5 GPM Outdoor Natural Gas Tankless Heater
The Rheem RTG-95XLN-3 increases water delivery to 9.5 GPM, surpassing the 7.5 GPM flow rate of the Noritz NR98-OD NG. It features built-in WiFi, non-condensing outdoor operation, and a compact gray body measuring 20.8 inches high, 13.5 inches wide, and 9.4 inches long at 39.3 pounds. Compared to the Noritz, you give up the 199,000 BTU natural gas specification, 84% thermal efficiency rating, and 0.05 GPM low-flow activation rate. The Rheem also does not list the self-diagnostic computer system of the NR98-OD NG. Pick this Rheem model if you need higher GPM flow and want WiFi functionality in an outdoor unit.
Quick picks
Our 7 picks
Noritz 7.5 GPM Outdoor Natural Gas Water Heater
Best for: high-demand outdoor natural gas installations
- Fuel Type
- Natural Gas
- Flow Rate
- 7.5 GPM
- BTU
- 199,000 BTU
- Installation Location
- Outdoor
View on Amazon: Noritz 7.5 GPM Outdoor Natural Gas Water Heater
This outdoor tankless water heater runs on natural gas and delivers up to 7.5 GPM with a 199,000 BTU heat rating. It operates at 84% thermal efficiency and activates at a low 0.05 GPM flow rate. Because it mounts outdoors, you do not need dedicated venting hardware. It suits your home if you need a high-capacity exterior water heater that responds to minimal water draw.
Pros
- 199,000 BTU maximum heat output
- 0.05 GPM activation flow rate
- Outdoor installation requires no venting
- Self-diagnostic onboard computer system
Cons
- Outdoor installation only
- 84% thermal efficiency
- Limited to natural gas fuel
Good fit if
- You want an exterior natural gas unit that needs no indoor venting.
- You need a flow rate up to 7.5 GPM with low 0.05 GPM activation.
Skip if
- You need an indoor water heater.
- You prefer an efficiency rating higher than 84%.
Verdict: Noritz 7.5 GPM Outdoor Natural Gas Tankless Water Heater delivers 199,000 BTU performance with zero indoor venting requirements. Its 0.05 GPM activation rate ensures fast operation even at minimal water flow.
Rinnai 7.5 GPM Outdoor Natural Gas Tankless Water Heater
Best for: outdoor natural gas homes running multiple fixtures
- Fuel Type
- Natural Gas
- 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
This Rinnai tankless water heater runs on natural gas and mounts outdoors. It delivers a flow rate of up to 7.5 GPM, which provides enough hot water to run up to 6 appliances at once. Measuring 35 by 14.5 by 22 inches, it fits outside wall spaces while freeing up indoor utility room area. This unit suits you if you need reliable outdoor natural gas heating matched to standard multi-fixture household demands.
Pros
- Delivers up to 7.5 GPM flow rate to serve up to 6 appliances at once
- Outdoor installation eliminates indoor utility space requirements
- Includes 12-year heat exchanger, 5-year parts, and 1-year labor residential warranty
Cons
- Requires professional technician installation per manufacturer guidelines
- Requires specific Ubbink Concentric adapter for twin pipe PVC or CPVC venting configurations
Good fit if
- You need an outdoor natural gas heater delivering up to 7.5 GPM.
- You operate up to 6 hot water appliances at the same time.
- You want a 12-year residential factory warranty on the heat exchanger.
Skip if
- You require a flow capacity greater than 7.5 GPM for peak household demand.
- You intend to install the equipment without a qualified professional technician.
Verdict: Rinnai 7.5 GPM Outdoor Natural Gas Tankless delivers consistent outdoor heating capacity to support multiple simultaneous fixtures. Its solid 12-year heat exchanger warranty makes it a direct replacement option for matching outdoor systems.
Noritz 9.8 GPM Natural Gas Tankless Water Heater
Best for: heavy-duty indoor or outdoor natural gas setups
- Fuel Type
- Natural Gas
- Flow Rate
- 9.8 GPM
- Installation Location
- Indoor/Outdoor
- Dimensions
- 13.8 × 10.6 × 23.6 inches
- Weight
- 54 pounds
View on Amazon: Noritz 9.8 GPM Natural Gas Tankless Water Heater
This natural gas tankless water heater delivers flow rates up to 9.8 GPM for indoor or outdoor installations. It features a commercial-grade copper heat exchanger built with 25 percent thicker piping than standard units. You receive an included remote thermostat and a six-foot power cord in the box. It suits you if you need high-demand water heating with dual-unit connection support.
Pros
- Flow rate delivers up to 9.8 GPM
- Commercial-grade copper heat exchanger with 25% thicker piping
- Includes remote thermostat and 6-foot power cord
- Supports linking two units using QC-2 Quick Connect Cord
Cons
- Unit weight is 54 pounds
- QC-2 Quick Connect Cord not included
Good fit if
- You want a heavy-duty copper heat exchanger with thicker piping.
- You need flexible indoor or outdoor natural gas installation.
- You plan to link two units together for increased capacity.
Skip if
- You require liquid propane instead of natural gas.
- You need a lightweight heater under 50 pounds.
Verdict: Noritz Natural Gas Indoor/Outdoor Tankless Water Heater provides durable commercial-grade copper construction and flexible placement. It delivers high-capacity output with the option to link two units together.
Ranein 8.5 GPM Outdoor Natural Gas Water Heater
Best for: multi-fixture outdoor installations below 2,000 feet
- Fuel Type
- Natural Gas
- Flow Rate
- 8.5 GPM
- BTU
- 190,000 BTU/hr
- Installation Location
- Outdoor
- Dimensions
- 24.3 x 15.1 x 8.1 inches
- Weight
- 44 pounds
View on Amazon: Ranein 8.5 GPM Outdoor Natural Gas Water Heater
This Ranein outdoor tankless water heater runs on natural gas and delivers up to 8.5 GPM with a 190,000 BTU heating capacity. It connects using standard 3/4-inch NPT fittings and features a variable-speed bottom blower with built-in freeze protection. If you need whole-home outdoor hot water capacity serving four to six outlets simultaneously without dedicating indoor wall space, this unit fits your setup.
Pros
- High heating capacity of 190,000 BTU with up to 8.5 GPM flow rate
- Bottom-mounted variable-speed fan adapts to external wind pressure
- Uses standard 3/4-inch NPT gas and water inlet connections
- Equipped with internal anti-freeze protection
Cons
- Not recommended for elevations above 2,000 feet
- Requires manual draining through the pressure relief valve during extended freezes
- Restricted to outdoor installation
Good fit if
- You need an outdoor natural gas unit capable of supplying four to six outlets.
- You live at an elevation below 2,000 feet.
- You have standard 3/4-inch NPT plumbing and gas connections ready.
Skip if
- You live at an altitude higher than 2,000 feet.
- You require an indoor installation.
- You use liquid propane instead of natural gas.
Verdict: Ranein 8.5 GPM Outdoor Natural Gas Tankless Water Heater delivers 190,000 BTU and multi-fixture output for low-elevation exterior setups. It provides high flow rates using standard connections without taking up interior space.
Rinnai 7.6 GPM Outdoor Natural Gas Water Heater
Best for: outdoor natural gas setups needing multi-fixture flow
- Fuel Type
- Natural Gas
- Flow Rate
- 7.6 GPM
- Installation Location
- Outdoor
- Dimensions
- 24.6 x 14.1 x 10.8 in
- Venting Type
- Non-Condensing
- Weight
- 53.3 pounds
View on Amazon: Rinnai 7.6 GPM Outdoor Natural Gas Water Heater
The Rinnai 7.6 GPM Outdoor Natural Gas Tankless Heater provides on-demand hot water without taking up indoor square footage. It delivers up to 7.6 GPM, supporting up to six fixtures simultaneously. Designed for outdoor installation, this non-condensing unit measures 24.6 by 14.1 by 10.8 inches and weighs 53.3 pounds. It suits you if you need a dependable outdoor natural gas heater with an onboard LED diagnostic display.
Pros
- Delivers up to 7.6 GPM to supply up to 6 fixtures at once
- Outdoor non-condensing build saves interior utility space
- LED screen shows service reminders and diagnostic error codes
- 15-year limited heat exchanger warranty when registered within 90 days
Cons
- WiFi monitoring requires purchasing a separate Controlr module
- Internal recirculation pump is not included
- Labor warranty drops to 1 year if not registered within 90 days
Good fit if
- You need an outdoor natural gas setup serving up to 6 fixtures.
- You want diagnostic codes and maintenance reminders on an integrated LED display.
- You plan to mount the heater outdoors without routing indoor exhaust venting.
Skip if
- You need an indoor-mounted water heater.
- You want built-in WiFi connectivity out of the box.
- You require an integrated recirculation pump.
Verdict: Rinnai 7.6 GPM Outdoor Natural Gas Tankless Heater delivers solid outdoor flow rates and clear LED error reporting. It serves as a capable natural gas alternative if you do not need built-in WiFi or an internal pump.
APUS 190,000 BTU Outdoor Natural Gas Water Heater
Best for: outdoor natural gas homes needing smart control
- Fuel Type
- Natural Gas
- Flow Rate
- 8.1 GPM
- BTU
- 190,000 BTU
- Installation Location
- Outdoor
- Voltage
- 120V AC
- Temperature Control
- 95°F–149°F, ±1°F
View on Amazon: APUS 190,000 BTU Outdoor Natural Gas Water Heater
This outdoor natural gas tankless water heater delivers up to 8.1 GPM with a 190,000 BTU heat output. It operates on a 120V AC connection with 3/4-inch gas and water fittings. You can adjust water temperatures between 95°F and 149°F using a wired controller or the Tuya mobile app. It suits you if you need a high-capacity outdoor system for multiple simultaneous fixtures.
Pros
- 8.1 GPM flow rate with 190,000 BTU maximum output
- Digital controls via Tuya app or wired controller from 95°F to 149°F
- Standard 3/4-inch water and gas connections
- Low minimum activation flow rate of 0.79 GPM
Cons
- Outdoor installation only
- Limited to a 2-year warranty on all components
Good fit if
- You need an outdoor natural gas heater delivering up to 8.1 GPM.
- You want mobile app or wired control for temperature settings.
- You have existing 3/4-inch plumbing and gas supply lines.
Skip if
- You need an indoor tankless installation.
- You require component warranty coverage longer than 2 years.
Verdict: APUS 8.1 GPM Outdoor Natural Gas Tankless Water Heater provides 190,000 BTU and app-enabled controls for high-demand outdoor setups. It delivers strong flow capacity through standard 3/4-inch connections.
Rheem RTG 9.5 GPM Outdoor Natural Gas Tankless Heater
Best for: outdoor natural gas setups needing 9.5 GPM
- Fuel Type
- Natural Gas
- Flow Rate
- 9.5 GPM
- BTU
- 199,900 BTU/hr
- Installation Location
- Outdoor
- Temperature Control
- ±1°F
- Certification
- CSA
View on Amazon: Rheem RTG 9.5 GPM Outdoor Natural Gas Tankless Heater
The Rheem RTG Series 9.5 GPM Outdoor Tankless is a natural gas water heater engineered for exterior mounting. Delivering up to 9.5 GPM at a 35°F temperature rise with a 199,900 BTU burner, it supplies enough capacity for three to four simultaneous showers. If you run multiple hot water fixtures at once and want an exterior unit with a 0.82 UEF rating that requires no indoor venting, this model fits your household.
Pros
- Delivers up to 9.5 GPM flow rate at a 35°F temperature rise with a 199,900 BTU output
- Outdoor wall-mounted design requires no indoor exhaust venting
- Digital LED control panel enables precise adjustments in 1°F increments
- Backed by a 15-year heat exchanger and 5-year parts warranty
Cons
- Non-condensing efficiency is limited to a 0.82 Uniform Energy Factor
- Base configuration lacks built-in Wi-Fi connectivity
Good fit if
- You need high flow rates to support up to four simultaneous showers.
- You have an exterior wall location and want to avoid installing indoor venting.
- You use natural gas and want precision single-degree temperature settings.
Skip if
- You require an indoor-rated water heater installation.
- You want built-in Wi-Fi monitoring included out of the box.
Verdict: Rheem RTG Series 9.5 GPM Outdoor Tankless provides high-output 199,900 BTU heating capacity for multi-bath homes without requiring indoor exhaust ducts. It delivers reliable whole-house hot water backed by a 15-year heat exchanger warranty.
Specifications side by side
| Spec | Noritz 7.5 GPM Outdoor Natural Gas Water Heater | Rinnai 7.5 GPM Outdoor Natural Gas Tankless Water Heater | Noritz 9.8 GPM Natural Gas Tankless Water Heater | Ranein 8.5 GPM Outdoor Natural Gas Water Heater | Rinnai 7.6 GPM Outdoor Natural Gas Water Heater | APUS 190,000 BTU Outdoor Natural Gas Water Heater | Rheem RTG 9.5 GPM Outdoor Natural Gas Tankless Heater |
|---|---|---|---|---|---|---|---|
| Fuel Type | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas |
| Flow Rate | 7.5 GPM | 7.5 GPM | 9.8 GPM | 8.5 GPM | 7.6 GPM | 8.1 GPM | 9.5 GPM |
| BTU | 199,000 BTU | not specified | not specified | 190,000 BTU/hr | not specified | 190,000 BTU | 199,900 BTU/hr |
| Installation Location | Outdoor | Outdoor | Indoor/Outdoor | Outdoor | Outdoor | Outdoor | Outdoor |
| Voltage | not specified | not specified | not specified | not specified | not specified | 120V AC | not specified |
| Temperature Control | not specified | not specified | not specified | not specified | not specified | 95°F–149°F, ±1°F | ±1°F |
| Certification | not specified | not specified | not specified | not specified | not specified | not specified | CSA |
| Dimensions | not specified | 35 x 14.5 x 22 inches | not specified | 24.3 x 15.1 x 8.1 inches | 24.6 x 14.1 x 10.8 in | 22.48 x 15.51 x 6.54 in | 20.8 x 13.5 x 9.4 inches |
| Venting Type | not specified | not specified | not specified | not specified | Non-Condensing | not specified | Non-Condensing |
| Features | not specified | not specified | not specified | not specified | not specified | not specified | WiFi |
| Weight | not specified | not specified | 54 pounds | 44 pounds | 53.3 pounds | 42.5 pounds | 39.3 pounds |
| Size | 7.5 GPM | 7.5 GPM | 9.375 inches | 8.5 GPM Outdoor | 9.8 GPM | not specified | 9.5 GPM (No WiFi) |
| Color | Beige | Outdoor Installation | Beige | Gray-NG | Silver | Gray | Gray |
| Model | NR98-OD NG | RUS75eN | NR98SVNG | RHO19K-NG | REU-VE2737WD-US-N | AP-AWH-W26NG | RTG-95XLN-3 |
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Frequently asked questions
Can I install any of these alternatives in an indoor space?
Most options on this list are designed for outdoor use. The Noritz NR98SVNG is a notable exception, as it supports flexible placement for both indoor and outdoor natural gas setups. Other models, such as the Rinnai RUS75eN and the APUS unit, are strictly for exterior installation. Always check the specific installation location requirements for your chosen model before proceeding.
Do these tankless heaters require special venting compared to the Noritz NR98-OD NG?
The Noritz NR98-OD NG requires zero indoor venting. Similarly, the Rinnai REU-VE2737WD-US-N and the Rheem RTG-95XLN-3 use non-condensing venting methods. This means they exhaust directly outdoors without needing complex indoor ductwork. Most units on this list are built for exterior exhaust, simplifying the installation process for outdoor setups.
Which alternative offers the highest flow rate for multiple bathrooms?
If you need maximum output, the Rheem RTG Series provides a 9.5 GPM flow rate. This high capacity supports multi-bath homes with its 199,900 BTU heating power. The Noritz NR98SVNG also delivers high-capacity output, though its listed flow rate is 7.5 GPM. These units handle heavy-duty demands better than standard 7.5 GPM models.
Are there smart control features available in these outdoor units?
Yes, some models include modern connectivity. The Rheem RTG Series and the APUS unit both offer WiFi capabilities for app-enabled controls. This allows you to monitor and adjust settings remotely. Other units, like the Rinnai RUS75eN, do not include built-in WiFi but provide clear LED error reporting for easy troubleshooting.
How do the dimensions of these heaters compare for wall mounting?
Sizes vary significantly across brands. The Rinnai RUS75eN is quite tall at 35 inches high, while the APUS unit is more compact at 22.5 inches high. The Rheem RTG-95XLN-3 is also shorter at 20.8 inches high. Check the width and length specs, such as the Rinnai’s 14.5-inch width, to ensure they fit your available outdoor wall space.
Is copper construction available in any of these natural gas water heaters?
The Noritz NR98SVNG features durable commercial-grade copper construction. This material choice supports its flexible placement options and high-capacity output. Other models on the list do not specify copper heat exchangers in the provided data. If you prioritize this specific material, the Noritz premium option is your primary choice among these alternatives.
Can I link multiple units together for higher capacity?
The Noritz NR98SVNG allows you to link two units together to boost performance. This feature is useful for very high-demand scenarios. The other models listed, including the Rinnai and Rheem options, do not mention multi-unit linking capabilities in their specifications. You would need to rely on the single unit’s maximum flow rate for these brands.