Looking Beyond the A. O. Smith ProLine XE Outdoor Natural? 6 Alternatives Worth a Look
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If you are evaluating a o smith proline xe outdoor natural alternatives, you likely value its 120,000 BTU/hr output and 6.6 GPM flow rate. The unit uses a copper heat exchanger for stable temperatures and fits outdoor spaces with its compact 22.9-inch height. However, you might prefer a different fuel type, such as propane, or a higher flow rate for larger households. Some buyers also seek indoor models with recirculation or specific venting requirements that this outdoor unit cannot meet. The listed alternatives were chosen because their core specifications overlap with these needs, offering comparable performance in key areas.
This guide compares seven units based strictly on published data. You will see options ranging from 6.1 GPM to 8.4 GPM flow rates. Some models prioritize compact dimensions, while others focus on raw heating power or smart connectivity. Each entry highlights how its specs align with or differ from the A. O. Smith baseline. You can use these comparisons to identify the best fit for your home’s specific hot water demands and installation constraints without guessing at performance.
Our top pick: A. O. Smith ProLine XE Outdoor Natural Gas Heater.
Key differences in flow and fuel
Rinnai 6.1 GPM Outdoor Propane Water Heater
The Rinnai RE160eP uses propane instead of natural gas, which changes your fuel infrastructure needs. It offers a similar 6.6 GPM flow rate but relies on non-condensing technology, unlike the A. O. Smith’s condensing design. This unit is slightly taller at 24.6 inches but narrower in width. You get a compact footprint that fits tight outdoor spaces. The trade-off is the need for a propane tank or delivery service rather than a natural gas line. Choose this if you already have propane access and want a durable, silver-finished unit that prioritizes heat stability over smart connectivity.
Westinghouse 8.1 GPM Outdoor Natural Gas Heater
The Westinghouse HS180A0G-NG delivers a higher 8.1 GPM flow rate, making it better for busy households with multiple simultaneous uses. It runs on natural gas like the A. O. Smith but is physically larger, standing 26.8 inches tall. You gain significant hot water capacity for whole-home demand. The trade-off is a bulkier 17.1-inch width and lack of specified smart features or advanced diagnostics. This unit suits buyers who prioritize raw flow volume over compact dimensions or specific heat exchanger materials. It is a practical choice for large families needing maximum outdoor hot water output without extra complexity.
Rheem RTG 8.4 GPM Outdoor Natural Gas Tankless Heater
The Rheem RTG-84XLN-3 provides an 8.4 GPM flow rate, the highest in this comparison, ideal for large families. It includes WiFi connectivity, allowing remote control and monitoring, which the A. O. Smith lacks. The unit is shorter at 20.8 inches but narrower in depth. You trade some compactness for advanced digital control and higher capacity. The non-condensing design differs from the A. O. Smith’s efficiency features. Choose this model if you need precise temperature settings and smart home integration alongside high-volume hot water. It fits users who value technology and maximum flow over the copper heat exchanger durability.
Rinnai 7.5 GPM Outdoor Natural Gas Tankless Water Heater
The Rinnai RUS75eN offers a 7.5 GPM flow rate, surpassing the A. O. Smith’s 6.6 GPM for faster hot water delivery. It is significantly taller at 35 inches, requiring more vertical space for installation. The unit runs on natural gas and is designed for outdoor use. You gain higher capacity but lose the compact profile of the A. O. Smith. This model suits homes needing maximum hot water speed outdoors. It lacks specified smart features or advanced diagnostics. Pick this unit if you prioritize flow rate and can accommodate a taller unit, ensuring consistent performance for high-demand outdoor fixtures.
Rinnai Smart-Circ 6.1 GPM Natural Gas Heater
The Rinnai REP160iN is designed for indoor installation, unlike the outdoor-only A. O. Smith. It offers a 6.6 GPM flow rate with recirculation capabilities, reducing wait times for hot water. The unit is taller at 27.3 inches and heavier at 51 pounds. You gain indoor flexibility and energy efficiency from recirculation but lose outdoor weather resistance. This model suits homes needing efficient indoor hot water with compact sizing. It lacks smart features but provides reliable performance. Choose this if you need to place the heater inside and value recirculation technology over outdoor durability or higher flow rates.
Noritz Outdoor Natural Gas Water Heater 6.6 GPM
The Noritz NR662-OD-NG provides a 6.6 GPM flow rate, matching the A. O. Smith, but is lighter at 36 pounds. It is designed for outdoor use with natural gas. The unit is slightly taller at 26.6 inches but narrower in width. You gain a lighter, compact option for single-bathroom setups or smaller spaces. The trade-off is the lack of specified smart features or advanced diagnostics. This model suits buyers needing reliable outdoor performance without extra bulk. Pick this unit if you prioritize weight and compactness for small outdoor areas, ensuring steady hot water for limited fixtures.
Quick picks
Our 7 picks
A. O. Smith ProLine XE Outdoor Natural Gas Heater
Best for: Outdoor installations valuing heat stability
- Fuel Type
- Natural Gas
- Flow Rate
- 6.6 GPM
- BTU
- 120,000 BTU
- Installation Location
- Outdoor
- Venting Type
- Condensing
- Dimensions
- 13.9 × 13.9 × 22.9 inches
View on Amazon: A. O. Smith ProLine XE Outdoor Natural Gas Heater Affiliate link
This outdoor unit delivers 6.6 GPM of hot water using 120,000 BTU of natural gas. Its copper heat exchanger stabilizes temperatures faster than stainless steel models. The compact wall-mount design saves space, and it vents through 3-inch or 4-inch PVC pipe. You get integrated controls and diagnostics for easier maintenance. This model suits homes needing reliable outdoor heating with efficient heat transfer.
Pros
- 6.6 GPM continuous flow rate
- 120,000 BTU/hr input
- Copper heat exchanger for faster stabilization
- Flexible 3" or 4" PVC venting
Cons
- Lower flow rate than some competitors
- Heavier build at 50 pounds
- No smart connectivity features listed
Good fit if
- You need a durable outdoor unit
- You prefer copper heat exchangers
- You want simple integrated controls
Skip if
- You need more than 6.6 GPM
- You want indoor installation only
- You require smart home integration
Verdict: A. O. Smith ProLine XE 6.6 GPM Outdoor is a solid choice for homeowners who prioritize heat exchanger durability and straightforward operation over high flow rates or smart features.
Rinnai 6.1 GPM Outdoor Propane Water Heater
Best for: propane outdoor installations
- Fuel Type
- Propane
- Flow Rate
- 6.1 GPM
- BTU
- 160k BTU
- Installation Location
- Outdoor
- Dimensions
- 24.6 x 14.1 x 10.8 in
- Venting Type
- Non-Condensing
View on Amazon: Rinnai 6.1 GPM Outdoor Propane Water Heater Affiliate link
The Rinnai RE160eP is a non-condensing outdoor tankless water heater designed for propane fuel. It delivers a flow rate of 6.6 GPM, supporting up to five simultaneous fixtures. The unit measures 24.6 x 14.1 x 10.8 inches and weighs 49.2 pounds. Its compact, suitcase-sized design simplifies installation and service. This model suits users seeking a durable, energy-efficient solution for outdoor propane applications.
Pros
- 6.6 GPM flow rate supports five fixtures
- Compact 24.6 x 14.1 x 10.8 inch footprint
- 15-year limited warranty on the heat exchanger
- Non-condensing outdoor design for propane
Cons
- Requires propane fuel, not natural gas
- WiFi control module sold separately
- Labor warranty drops to 1 year if not registered within 90 days
Good fit if
- You need a propane-powered outdoor unit
- You want a compact footprint for easy installation
- You value a long heat exchanger warranty
Skip if
- You require natural gas compatibility
- You need built-in WiFi connectivity
- You prefer a condensing model
Verdict: Rinnai RE160eP Propane Outdoor Tankless is a compact, durable option for homes using propane. It fits users who need reliable hot water for multiple fixtures without the bulk of larger units.
Westinghouse 8.1 GPM Outdoor Natural Gas Heater
Best for: High-flow outdoor whole-home needs
- Fuel Type
- Natural Gas
- Flow Rate
- 8.1 GPM
- BTU
- 180,000 BTU
- Installation Location
- Outdoor
- Voltage
- 120V AC
- Temperature Control
- 95–158°F, ±1°F
View on Amazon: Westinghouse 8.1 GPM Outdoor Natural Gas Heater Affiliate link
The Westinghouse 8.1 GPM outdoor unit delivers 180,000 BTU for whole-home hot water. It maintains temperature within ±1°F using self-modulating technology. CSA certification ensures safe outdoor operation. You get precise control and freeze protection in a compact 26.8-inch frame. This model suits households needing high flow for multiple fixtures simultaneously.
Pros
- 8.1 GPM flow rate supports 3–5 fixtures
- 180,000 BTU heating capacity
- ±1°F temperature stability
- CSA certified for outdoor use
Cons
- Short 2-year limited warranty for the unit
- Heavier at 42 pounds
- No smart connectivity mentioned in data
Good fit if
- You need high flow for multiple bathrooms
- You require outdoor installation
- You want precise temperature control
Skip if
- You need indoor placement
- You prefer propane fuel
- You want smart home integration
Verdict: Westinghouse 8.1 GPM Outdoor Natural Gas offers strong heating power and stable temperatures for busy households. It fits users who prioritize flow rate and outdoor durability over long-term warranty coverage.
Rheem RTG 8.4 GPM Outdoor Natural Gas Tankless Heater
Best for: High-demand outdoor households
- Fuel Type
- Natural Gas
- Flow Rate
- 8.4 GPM
- BTU
- 180,000 BTU/hr
- Installation Location
- Outdoor
- Temperature Control
- ±1°F
- Certification
- CSA
View on Amazon: Rheem RTG 8.4 GPM Outdoor Natural Gas Tankless Heater Affiliate link
This Rheem unit delivers 8.4 GPM at a 35°F rise, powered by 180,000 BTUs. It is a non-condensing natural gas heater designed for outdoor mounting. The digital LED panel allows ±1°F temperature adjustments. It includes built-in freeze protection and flame failure safety. The metal cabinet supports wall installation. This model suits large households needing high flow rates for multiple simultaneous showers.
Pros
- 8.4 GPM flow rate for whole-house use
- 180,000 BTU/hr output
- Precision ±1°F temperature control
- Built-in freeze protection
- CSA certified for safety
Cons
- No WiFi connectivity in this 8.4 GPM variant
- Professional installation is required
- Non-condensing design may be less efficient than condensing models
Good fit if
- You need high flow for 3-4 simultaneous showers
- You have an outdoor space for wall mounting
- You want precise temperature control without app dependency
Skip if
- You require smart home integration or remote control
- You need indoor installation capabilities
- You prefer a smaller, lighter unit under 30 pounds
Verdict: Rheem RTG-84XLN 8.4 GPM Outdoor Heater provides robust hot water for large families. It fits buyers who prioritize raw flow rate and precise temperature settings over smart features.
Rinnai 7.5 GPM Outdoor Natural Gas Tankless Water Heater
Best for: High-flow outdoor natural gas needs
- 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 Affiliate link
The Rinnai RUS75eN delivers up to 7.5 GPM of hot water using natural gas. Its compact outdoor design measures 35 by 14.5 by 22 inches. This unit supports flexible venting options, including PVC or CPVC. It provides a constant stream for up to six appliances. You should choose this model if you need high flow rates for outdoor installation.
Pros
- 7.5 GPM flow rate
- Natural Gas fuel type
- Outdoor installation ready
- 12-year heat exchanger warranty
Cons
- No smart connectivity features listed
- Professional installation required
- Larger footprint than 6.6 GPM competitors
Good fit if
- You need the highest flow rate in this group
- You have an outdoor natural gas line
- You want a durable heat exchanger warranty
Skip if
- You prefer propane fuel
- You need indoor installation only
- You require smart home integration
Verdict: Rinnai 7.5 GPM Natural Gas Outdoor Heater suits homes needing maximum hot water capacity outdoors. It fits buyers prioritizing flow speed over smart features.
Rinnai Smart-Circ 6.1 GPM Natural Gas Heater
Best for: Indoor homes needing recirculation
- Fuel Type
- Natural Gas
- Flow Rate
- 6.6 GPM
- Installation Location
- Indoor
- Dimensions
- 27.3 x 14.1 x 10.8 inches
- Weight
- 51 pounds
View on Amazon: Rinnai Smart-Circ 6.1 GPM Natural Gas Heater Affiliate link
The Rinnai REP160iN is a non-condensing indoor tankless water heater designed for natural gas. It delivers 6.1 GPM of hot water, supporting up to five simultaneous fixtures. Its compact dimensions of 27.3 by 14.1 by 10.8 inches allow for flexible installation in tight spaces. The unit includes a built-in recirculation pump with Smart-Circ technology to learn your usage patterns. This model is ideal for homes requiring efficient, continuous hot water indoors.
Pros
- Built-in Smart-Circ recirculation pump for energy efficiency
- Compact size fits small indoor spaces
- 15-year heat exchanger warranty
- Supports up to five fixtures at 6.1 GPM
Cons
- Lower flow rate than outdoor competitors
- WiFi control module sold separately
- Indoor installation only
Good fit if
- You need a compact indoor unit
- You want built-in recirculation
- You prefer natural gas fuel
Skip if
- You require outdoor installation
- You need higher than 6.1 GPM flow
- You want included WiFi control
Verdict: The Rinnai REP160iN Indoor Natural Gas Heater fits homes needing efficient indoor hot water with recirculation. It suits buyers prioritizing compact size and long-term warranty over maximum flow rate.
Noritz Outdoor Natural Gas Water Heater 6.6 GPM
Best for: small outdoor spaces with one bathroom
- Fuel Type
- Natural Gas
- Flow Rate
- 6.6 Gpm
- BTU
- 140,000 Btuh
- Installation Location
- Outdoor
- Dimensions
- 26.6 x 17.6 x 10.7 inches
- Weight
- 36 pounds
View on Amazon: Noritz Outdoor Natural Gas Water Heater 6.6 GPM Affiliate link
This Noritz unit delivers 6.6 gallons per minute using 140,000 BTUs of natural gas. It is built specifically for outdoor installation and carries a 0.81 Energy Factor. The compact 36-pound frame fits tight spaces. You get endless hot water with low NOx emissions. It suits single-bathroom homes or small outdoor kitchens where space and efficiency matter.
Pros
- 6.6 GPM flow rate for steady hot water
- 140,000 BTU heating capacity
- 0.81 Energy Factor for efficiency
- Designed for outdoor use
Cons
- Lower flow rate than 8.4 GPM competitors
- No smart control or app integration
- Basic exterior with no finish
Good fit if
- You need a dedicated outdoor unit
- You prioritize high energy efficiency
- You have limited installation space
Skip if
- You require multiple simultaneous showers
- You want smart home connectivity
- You need indoor installation
Verdict: Noritz NR66ODNG 6.6 GPM Outdoor Heater is a compact, efficient choice for single-bathroom setups. It fits buyers who need reliable outdoor performance without smart features.
Specifications side by side
| Spec | A. O. Smith ProLine XE Outdoor Natural Gas Heater | Rinnai 6.1 GPM Outdoor Propane Water Heater | Westinghouse 8.1 GPM Outdoor Natural Gas Heater | Rheem RTG 8.4 GPM Outdoor Natural Gas Tankless Heater | Rinnai 7.5 GPM Outdoor Natural Gas Tankless Water Heater | Rinnai Smart-Circ 6.1 GPM Natural Gas Heater | Noritz Outdoor Natural Gas Water Heater 6.6 GPM |
|---|---|---|---|---|---|---|---|
| Fuel Type | Natural Gas | Propane | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas |
| Flow Rate | 6.6 GPM | 6.1 GPM | 8.1 GPM | 8.4 GPM | 7.5 GPM | 6.6 GPM | 6.6 Gpm |
| BTU | 120,000 BTU | 160k BTU | 180,000 BTU | 180,000 BTU/hr | not stated | not stated | 140,000 Btuh |
| Installation Location | Outdoor | Outdoor | Outdoor | Outdoor | Outdoor | Indoor | Outdoor |
| Voltage | not stated | not stated | 120V AC | not stated | not stated | not stated | not stated |
| Temperature Control | not stated | not stated | 95–158°F, ±1°F | ±1°F | not stated | not stated | not stated |
| Certification | not stated | not stated | CSA | CSA | not stated | not stated | not stated |
| Dimensions | not stated | 24.6 x 14.1 x 10.8 in | 26.8 x 17.1 x 17.1 inches | 20.8 x 13.5 x 9.4 inches | 35 x 14.5 x 22 inches | 27.3 x 14.1 x 10.8 inches | 26.6 x 17.6 x 10.7 inches |
| Use | not stated | not stated | Whole House | not stated | not stated | not stated | not stated |
| Venting Type | Condensing | Non-Condensing | not stated | Non-Condensing | not stated | not stated | not stated |
| Features | not stated | not stated | not stated | WiFi | not stated | not stated | not stated |
| Weight | 50 pounds | 49.2 pounds | 42 pounds | 39.3 pounds | not stated | 51 pounds | 36 pounds |
| Color | White | Silver | Grey 81NO | Gray | Outdoor Installation | Silver | No Finish |
| Model | ATO-140H 100 | REU-VE2125WD-US-P | HS180A0G-NG | RTG-84XLN-3 | RUS75eN | REU-VEP2125FFD-US-N | NR662-OD-NG |
| Size | not stated | 6.6 GPM | not stated | 8.4 GPM (No WiFi) | 7.5 GPM | 6.6 GPM | not stated |
When you need filtration alongside heating, compare published specifications for a o smith whole house water filter alternatives.
Frequently asked questions
Which outdoor tankless heater offers the highest flow rate?
The Rheem RTG-84XLN-3 provides the highest flow rate at 8.4 GPM. This capacity supports high-demand households with multiple simultaneous fixtures. It operates on natural gas and includes WiFi connectivity for remote monitoring. The unit measures 20.8 inches in height and weighs 39.3 pounds, making it a robust choice for large families.
Can I use propane instead of natural gas for outdoor heating?
Yes, the Rinnai REU-VE2125WD-US-P runs on propane. It delivers a 6.6 GPM flow rate suitable for multiple fixtures. This non-condensing model is compact, measuring 24.6 inches tall and 14.1 inches wide. It weighs 49.2 pounds, offering a durable option for homes already equipped with propane infrastructure rather than natural gas lines.
What is the smallest outdoor unit by weight?
The Noritz NR662-OD-NG is the lightest outdoor option at 36 pounds. It provides 6.6 GPM of hot water on natural gas. Its compact dimensions are 26.6 inches high and 17.6 inches wide. This unit is ideal for small outdoor spaces or single-bathroom setups where weight and footprint are primary concerns.
Does any outdoor model include smart features?
The Rheem RTG-84XLN-3 includes WiFi connectivity. This allows you to monitor and control the heater remotely. It delivers 8.4 GPM on natural gas and measures 9.4 inches in depth. This is the only listed outdoor unit with explicit smart features, distinguishing it from other high-flow natural gas options like the A. O. Smith ProLine XE.
Which unit is best for high-flow budget-conscious buyers?
The Westinghouse HS180A0G-NG offers 8.1 GPM at a budget-friendly position. It runs on natural gas and is designed for outdoor installation. The unit weighs 42 pounds and stands 26.8 inches tall. It prioritizes heating power and stable temperatures, making it suitable for busy households that need high flow without premium pricing.
Is there an indoor alternative with recirculation?
The Rinnai REU-VEP2125FFD-US-N is designed for indoor installation. It provides 6.6 GPM on natural gas and includes recirculation capabilities. This model measures 27.3 inches in height and 14.1 inches in width. It weighs 51 pounds, offering a compact solution for homes needing efficient indoor hot water with reduced wait times.
How does the Rinnai 7.5 GPM compare to the A. O. Smith?
The Rinnai RUS75eN offers a higher flow rate of 7.5 GPM compared to the A. O. Smith’s 6.6 GPM. Both use natural gas for outdoor installation. The Rinnai unit is taller at 35 inches and wider at 22 inches. It suits users prioritizing maximum hot water capacity over the slightly more compact footprint of the A. O. Smith ProLine XE.