6 Best Alternatives to the Westinghouse Tankless Water Heater Gas (2026)
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If you are looking for westinghouse tankless water heater gas alternatives, this guide compares 6 models that share similar core specifications. The Westinghouse unit delivers 7.9 GPM and 180,000 BTU with precise ±1°F temperature stability and built-in WiFi. It also activates at low flow rates, making it suitable for homes with limited pressure. However, you might prefer a different brand, size, or feature set. Some buyers prioritize higher flow rates for larger households, while others need outdoor installation or compact footprints for tight spaces. Others may want to avoid smart features or seek longer warranty terms on the heat exchanger. We selected these alternatives because their published specs overlap with the original product’s key metrics. This list covers natural gas models with flow rates ranging from 5.0 to 9.2 GPM. You will find options for indoor whole-home use or specific climate needs. Each model meets standard residential plumbing requirements. We focus strictly on the data provided by manufacturers to help you compare capacity, dimensions, and fuel types. This approach ensures you find a unit that fits your home’s technical requirements without guesswork.
Our top pick: Westinghouse 7.9 GPM Natural Gas Tankless Water Heater.
Comparing key specs and features
Rinnai RE160iN 6.6 GPM Gas Water Heater
The Rinnai RE160iN offers a lower flow rate of 6.6 GPM compared to the Westinghouse 7.9 GPM. It uses a non-condensing venting system and weighs slightly more at 48.5 pounds. Its compact width of 14.1 inches fits tighter spaces. You get a long heat exchanger warranty, which adds value for long-term reliability. However, the reduced GPM means it may struggle to supply multiple showers simultaneously. This unit is best for smaller households or outdoor installations in mild climates where high flow is not critical. It lacks the smart WiFi features found in the Westinghouse model, focusing instead on basic mechanical performance.
Rheem RTG 8.4 GPM Indoor Natural Gas Water Heater
The Rheem RTG provides a higher flow rate of 8.4 GPM, beating the Westinghouse 7.9 GPM. It is designed for large families needing robust hot water volume. The unit weighs 46.5 pounds and measures 24.2 inches in height. It uses non-condensing venting and does not include WiFi connectivity. You trade smart app control for raw capacity and simpler operation. The narrower width of 13.5 inches allows for easier placement in utility closets. This heater is ideal if you prioritize maximum flow over remote monitoring. It delivers steady performance for busy households but requires standard installation without the convenience of digital adjustments or fault alerts via smartphone.
Rinnai 6.5 GPM Natural Gas Indoor Tankless Water Heater
The Rinnai RUCS65IN has a lower flow rate of 5.0 GPM, significantly less than the Westinghouse 7.9 GPM. It is taller at 35 inches but has a flexible venting design suitable for compact indoor spaces. The unit weighs no listed weight in the data but has a small footprint. It lacks WiFi and smart controls, focusing on mechanical simplicity. This model is best for homes with limited space or lower hot water demand. You give up high flow capacity and digital features for a more compact physical profile. It is a solid choice for installations where space is tight and professional venting is already planned, rather than for whole-home simultaneous use.
Rinnai Smart-Circ 6.1 GPM Natural Gas Heater
The Rinnai Smart-Circ offers a flow rate of 6.6 GPM, lower than the Westinghouse 7.9 GPM. It includes built-in recirculation efficiency with learned scheduling, a feature absent in the Westinghouse unit. The unit weighs 51 pounds and measures 27.3 inches in height. It uses non-condensing venting and lacks explicit WiFi specs in the data provided. You gain convenience through automated recirculation but lose higher flow capacity. This heater is ideal for homes prioritizing energy efficiency and reduced wait times for hot water. It is best for users who value integrated recirculation features over the higher GPM and smart app connectivity of the Westinghouse model.
A. O. Smith 8 GPM Indoor Natural Gas Tankless Water Heater
The A. O. Smith ATI-310CX3 provides an 8 GPM flow rate, slightly higher than the Westinghouse 7.9 GPM. It features copper components and scale prevention, emphasizing durability. The unit weighs 51 pounds and is narrower at 13.8 inches. It lacks WiFi and smart connectivity features. You trade digital control for robust construction and heat exchanger longevity. This heater is best for households valuing durability and high flow over remote management. It fits homes where copper components are preferred for water quality. The installation requires standard plumbing but does not offer the app-based monitoring or fault alerts available with the Westinghouse unit.
MIZUDO 7.9 GPM Natural Gas WiFi Heater
The MIZUDO HW180A0W-NG matches the Westinghouse 7.9 GPM flow rate and 180,000 BTU output. It includes built-in WiFi for remote control, similar to the Westinghouse. The unit weighs 39.6 pounds and is slightly narrower at 16.3 inches. It is designed for indoor use with natural gas. You get comparable performance with a similar feature set. The main difference is the brand and specific model design. This heater is ideal if you want the same flow and smart capabilities from a different manufacturer. It offers steady temperature control and remote monitoring, making it a direct alternative for users who prioritize both capacity and digital connectivity.
Quick picks
Our 7 picks
Westinghouse 7.9 GPM Natural Gas Tankless Water Heater
Best for: Indoor whole-home hot water with smart control
- Fuel Type
- Natural Gas
- Flow Rate
- 7.9 GPM
- BTU
- 180,000 BTU
- Installation Location
- Indoor
- Voltage
- 120 V AC
- Temperature Control
- 95°F–149°F, ±1°F
View on Amazon: Westinghouse 7.9 GPM Natural Gas Tankless Water Heater Affiliate link
This indoor natural gas unit delivers 7.9 GPM at 180,000 BTU. It maintains temperature within ±1°F using self-modulating technology. Built-in WiFi allows remote app control and voice commands. It activates at 0.53 GPM and 15 PSI. The 26.2-inch height fits standard indoor spaces. It suits homes needing whole-house hot water with smart features.
Pros
- 7.9 GPM flow rate supports three simultaneous showers
- Precise ±1°F temperature stability for consistent comfort
- Built-in WiFi enables app and voice control
- Activates at low 0.53 GPM flow and 15 PSI
Cons
- Only 2-year limited warranty on the complete unit
- Indoor installation only, not suitable for outdoor use
- Requires 120V AC power connection for operation
Good fit if
- You want precise temperature control within ±1°F
- You need remote monitoring via a smartphone app
- You have low water pressure or flow rates
Skip if
- You require outdoor installation capability
- You prefer a longer than 2-year unit warranty
- You need a propane fuel option
Verdict: Westinghouse 7.9 GPM Indoor Gas Heater offers precise temperature control and smart connectivity for indoor whole-home use. It is ideal for buyers who value remote management and reliable performance in low-pressure environments.
Rinnai RE160iN 6.6 GPM Gas Water Heater
Best for: outdoor use in warm climates
- Fuel Type
- Natural Gas
- Flow Rate
- 6.6 GPM
- BTU
- 160k BTU
- Installation Location
- Indoor
- Dimensions
- 27.3 x 14.1 x 10.8 inches
- Venting Type
- Non-Condensing
View on Amazon: Rinnai RE160iN 6.6 GPM Gas Water Heater Affiliate link
The Rinnai RE160iN is a non-condensing natural gas tankless water heater designed for outdoor installation. It delivers 6.6 GPM, supporting up to five simultaneous fixtures. The unit measures 27.3 by 14.1 by 10.8 inches and weighs 48.5 pounds. It features an LED screen for error codes and service reminders. This model suits homeowners in warmer climates who need a compact, durable outdoor solution with a strong heat exchanger warranty.
Pros
- Delivers 6.6 GPM flow rate for multiple fixtures
- Compact outdoor design fits small spaces
- 15-year limited warranty on the heat exchanger
- LED screen displays error codes and service reminders
Cons
- Lower 6.6 GPM flow rate compared to other list options
- Designed for outdoor installation only
- WiFi control module is sold separately
Good fit if
- You need a compact outdoor unit for a warm climate
- You want a strong heat exchanger warranty
- You prefer a non-condensing design
Skip if
- You require indoor installation
- You need a flow rate above 7.9 GPM
- You want included WiFi connectivity
Verdict: Rinnai RE160iN 6.6 GPM Natural Gas Heater fits outdoor installations in mild climates where a lower flow rate is acceptable. It offers a compact footprint and a long heat exchanger warranty for reliable performance.
Rheem RTG 8.4 GPM Indoor Natural Gas Water Heater
Best for: Large families needing high flow
- Fuel Type
- Natural Gas
- Flow Rate
- 8.4 GPM
- BTU
- 180,000 BTU/hr
- Installation Location
- Indoor
- Temperature Control
- ±1°F
- Certification
- CSA
View on Amazon: Rheem RTG 8.4 GPM Indoor Natural Gas Water Heater Affiliate link
The Rheem RTG Series delivers 8.4 GPM of hot water at 180,000 BTU/hr. This non-condensing indoor unit features a 0.82 UEF and ±1°F digital temperature control. It suits large families needing 3-4 simultaneous showers. The compact wall-mount design saves floor space. Professional installation is required for this natural gas model.
Pros
- 8.4 GPM flow rate for whole-house use
- 180,000 BTU/hr output capacity
- 0.82 Uniform Energy Factor (UEF)
- ±1°F precise digital temperature control
- 15-year heat exchanger warranty
Cons
- Heavier at 46.5 pounds
- Non-condensing design limits efficiency compared to condensing models
- Indoor installation only
Good fit if
- You need high flow for multiple bathrooms
- You want precise temperature adjustments
- You have indoor venting space
Skip if
- You need outdoor installation
- You prefer WiFi connectivity
- You want a condensing unit
Verdict: Rheem RTG 8.4 GPM Natural Gas provides robust flow and precise control for busy households. It fits homes requiring high-volume hot water without WiFi features.
Rinnai 6.5 GPM Natural Gas Indoor Tankless Water Heater
Best for: compact indoor spaces with flexible venting needs
- Fuel Type
- Natural Gas
- Flow Rate
- Up to 6.5 GPM
- Installation Location
- Indoor
- Dimensions
- 35 x 14.5 x 22 inches
View on Amazon: Rinnai 6.5 GPM Natural Gas Indoor Tankless Water Heater Affiliate link
This Rinnai unit delivers up to 6.5 GPM of hot water for indoor use. It runs on natural gas and measures 35 x 14.5 x 22 inches. The compact design fits tight spaces while serving up to five appliances. You get endless hot water with energy-efficient operation. Multiple venting options, including PVC, allow flexible placement. It is a reliable choice for homes needing steady flow without a large tank.
Pros
- 6.5 GPM flow rate serves up to five appliances
- Compact 35 x 14.5 x 22 inch footprint
- Flexible venting options including PVC/CPVC
- 12-year heat exchanger warranty
Cons
- Lower flow rate than competitors offering 7.9 to 8.4 GPM
- No smart connectivity or WiFi mentioned in specifications
- Professional installation is strongly recommended
Good fit if
- You need a compact unit for tight indoor spaces
- You want flexible venting options like PVC
- You prefer a trusted brand with strong warranty coverage
Skip if
- You require high flow rates above 7.5 GPM
- You want smart home integration or app control
- You are looking for outdoor installation models
Verdict: Rinnai RUCS65IN Natural Gas Indoor suits buyers who prioritize compact size and flexible venting over maximum flow rate. It is a solid pick for homes where space is limited and professional installation is already planned.
Rinnai Smart-Circ 6.1 GPM Natural Gas Heater
Best for: homes needing built-in recirculation efficiency
- 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 natural gas tankless water heater with a 6.6 GPM flow rate. It features built-in Smart-Circ recirculation technology that learns your usage patterns to schedule pump operation. The unit measures 27.3 x 14.1 x 10.8 inches and weighs 51 pounds. It includes a 15-year heat exchanger warranty. This model suits homes needing efficient hot water delivery without external pumps.
Pros
- Built-in Smart-Circ recirculation pump
- 6.6 GPM flow rate
- 15-year heat exchanger warranty
- Compact indoor design
Cons
- Lower 6.6 GPM flow rate than competitors
- WiFi control module sold separately
- Requires professional installation
Good fit if
- You want built-in recirculation without extra pumps
- You need a compact indoor unit
- You prefer long-term warranty coverage
Skip if
- You need higher than 6.6 GPM flow
- You want included WiFi connectivity
- You prefer DIY installation
Verdict: Rinnai REP160iN Smart-Circ 6.6 GPM fits homes prioritizing integrated recirculation efficiency over maximum flow speed. It is ideal for users who value the convenience of learned scheduling and long warranty protection.
A. O. Smith 8 GPM Indoor Natural Gas Tankless Water Heater
Best for: High-flow indoor households valuing durability
- Fuel Type
- Natural Gas, Propane
- Flow Rate
- 8.0 GPM
- Installation Location
- Indoor
- Dimensions
- 13.8 × 13.8 × 20.5 inches
- Weight
- 51 pounds
View on Amazon: A. O. Smith 8 GPM Indoor Natural Gas Tankless Water Heater Affiliate link
The A.O. Smith ATI-310CX3 delivers 8.0 GPM at 190,000 BTU for indoor natural gas use. It features a commercial-grade copper heat exchanger for superior heat transfer and X3 Scale Prevention Technology to reduce maintenance. Weighing 51 pounds, it measures 20.5 inches high. This unit suits homes needing high flow rates with durable internal components and flexible venting options.
Pros
- 8.0 GPM flow rate for multiple simultaneous uses
- 190,000 BTU output for strong heating performance
- Copper heat exchanger offers 25x better heat transfer than steel
- X3 Scale Prevention Technology reduces descaling needs
- Convertible from natural gas to propane with included kit
Cons
- Heavier at 51 pounds compared to lighter alternatives
- Lacks built-in WiFi connectivity found in some competitors
- Indoor installation only, not suitable for outdoor mounting
Good fit if
- You need high flow rates for large households
- You prefer durable copper heat exchangers over steel
- You want flexible venting options for indoor installation
Skip if
- You require outdoor installation capabilities
- You want smart home integration with WiFi
- You need a lighter unit for easier mounting
Verdict: A.O. Smith 8 GPM Natural Gas Indoor is a robust choice for households prioritizing flow rate and heat exchanger durability. It fits homes where copper components and scale prevention are valued over smart connectivity features.
MIZUDO 7.9 GPM Natural Gas WiFi Heater
Best for: Smart control and steady temperature
- Fuel Type
- Natural Gas
- Flow Rate
- Up to 7.9 GPM
- BTU
- 180,000 BTU/h
- Installation Location
- Indoor
- Voltage
- 120V AC
- Temperature Control
- 95 to 149°F, ±1°F
View on Amazon: MIZUDO 7.9 GPM Natural Gas WiFi Heater Affiliate link
This indoor natural gas unit delivers 7.9 GPM at 180,000 BTU. It includes WiFi control for remote temperature adjustments and monitoring via a smartphone app. The self-modulating gas control maintains stability within ±1°F. It uses a copper heat exchanger and sealed combustion. This model suits larger households with multiple simultaneous hot water draw points.
Pros
- 7.9 GPM flow rate at 180,000 BTU input
- WiFi app control for remote monitoring and settings
- Temperature stability within ±1°F
- Copper heat exchanger for efficient heat transfer
Cons
- Only 2-year unit coverage compared to industry standards
- Heavier at 39.6 pounds than some compact alternatives
- Requires 120V AC power for operation
Good fit if
- You need precise temperature control for multiple fixtures
- You want remote management via a smartphone app
- You have an indoor space for direct-vent installation
Skip if
- You require propane fuel compatibility
- You prefer a unit with a longer warranty period
- You need a lighter or more compact design
Verdict: MIZUDO 7.9 GPM Natural Gas WiFi Heater offers strong flow and smart control for busy households. It fits users who value remote monitoring and steady temperatures over extended warranty coverage.
Specifications side by side
| Spec | Westinghouse 7.9 GPM Natural Gas Tankless Water Heater | Rinnai RE160iN 6.6 GPM Gas Water Heater | Rheem RTG 8.4 GPM Indoor Natural Gas Water Heater | Rinnai 6.5 GPM Natural Gas Indoor Tankless Water Heater | Rinnai Smart-Circ 6.1 GPM Natural Gas Heater | A. O. Smith 8 GPM Indoor Natural Gas Tankless Water Heater | MIZUDO 7.9 GPM Natural Gas WiFi Heater |
|---|---|---|---|---|---|---|---|
| Fuel Type | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas, Propane | Natural Gas |
| Flow Rate | 7.9 GPM | 6.6 GPM | 8.4 GPM | Up to 6.5 GPM | 6.6 GPM | 8.0 GPM | Up to 7.9 GPM |
| BTU | 180,000 BTU | 160k BTU | 180,000 BTU/hr | not stated | not stated | not stated | 180,000 BTU/h |
| Installation Location | Indoor | Indoor | Indoor | Indoor | Indoor | Indoor | Indoor |
| Voltage | 120 V AC | not stated | not stated | not stated | not stated | not stated | 120V AC |
| Temperature Control | 95°F–149°F, ±1°F | not stated | ±1°F | not stated | not stated | not stated | 95 to 149°F, ±1°F |
| Certification | CSA | not stated | CSA | not stated | not stated | not stated | CSA |
| Dimensions | 26.2 x 17.1 x 17.1 in | 27.3 x 14.1 x 10.8 inches | 24.2 x 13.5 x 10.3 inches | 35 x 14.5 x 22 inches | 27.3 x 14.1 x 10.8 inches | not stated | 25 x 16.3 x 7.3 in |
| Use | Whole House | not stated | not stated | not stated | not stated | not stated | not stated |
| Venting Type | not stated | Non-Condensing | Non-Condensing | not stated | not stated | not stated | not stated |
| Features | WiFi | not stated | not stated | not stated | not stated | not stated | WiFi |
| Weight | 39.3 pounds | 48.5 pounds | 46.5 pounds | not stated | 51 pounds | 51 pounds | 39.6 pounds |
| Size | APOLO-180K | 6.6 GPM | 8.4 GPM (Standard) | 6.5 GPM | 6.6 GPM | not stated | Natural Gas, 7.9 GPM, 180,000 BTU, Indoor |
| Color | Grey 79NI | Silver | Gray | White | Silver | White | White 7.9N |
| Model | HW180A0G-NG | REU-VE2125FFD-US-N | RTG-84DVLN-3 | RUCS65IN | REU-VEP2125FFD-US-N | ATI-310CX3 | HW180A0W-NG |
If you require kitchen filtration, specifications for apec water apec tankless ro water alternatives outline daily flow capacities.
Frequently asked questions
Which gas tankless heater provides the highest flow rate for large families?
The Rheem RTG 8.4 GPM Indoor Natural Gas Water Heater offers the highest flow rate on this list. It delivers 8.4 gallons per minute to support busy households with multiple simultaneous uses. This model fits indoor installations and uses non-condensing venting. It provides robust performance without requiring smart connectivity features, making it a reliable choice for high-volume demand.
Is there a Westinghouse alternative with built-in WiFi for remote control?
The MIZUDO 7.9 GPM Natural Gas WiFi Heater is designed for smart control and steady temperatures. It includes WiFi connectivity for remote monitoring and management. This unit delivers 7.9 GPM with 180,000 BTU output. It fits indoor spaces and measures 16.3 inches wide. It is ideal for users who prioritize digital convenience over extended warranty coverage.
Which model is best for outdoor use in warm climates?
The Rinnai RE160iN 6.6 GPM Gas Water Heater is suitable for outdoor installations in mild climates. It provides a flow rate of 6.6 GPM, which is acceptable for warmer regions. This unit weighs 48.5 pounds and features a compact footprint. It uses non-condensing venting and includes a long heat exchanger warranty for reliable performance in specific environmental conditions.
Does any option include a recirculation pump for water efficiency?
The Rinnai Smart-Circ 6.1 GPM Natural Gas Heater features integrated recirculation efficiency. It helps reduce water waste by maintaining hot water availability through learned scheduling. This model delivers 6.6 GPM and fits indoor installations. It weighs 51 pounds and offers long warranty protection. It is ideal for users who value convenience and efficiency over maximum flow speed.
Which heater is the most compact for tight indoor spaces?
The Rheem RTG 8.4 GPM Indoor Natural Gas Water Heater has a narrow width of 13.5 inches. It also measures 10.3 inches in length, making it suitable for confined areas. This model weighs 46.5 pounds and uses non-condensing venting. It provides high flow rates without requiring additional space for smart components, fitting well in homes with limited installation room.
Is there a durable option with copper components for scale prevention?
The A. O. Smith 8 GPM Indoor Natural Gas Tankless Water Heater is built with copper components to prevent scale buildup. It delivers 8 GPM for high-flow households. This unit weighs 51 pounds and measures 13.8 inches wide. It prioritizes durability and heat exchanger longevity over smart connectivity features, making it a robust choice for long-term indoor use.