Best Gas Water Heaters Consumer Reports: Practical Features for Easier Everyday Use

A strong gas water heater delivers enough flow for your busiest fixtures, fits the available installation space, and includes controls and safety features suited to your home. This roundup focuses on 10 natural-gas tankless models ranging from 4.2 to 10.3 GPM and from 95,000 to 199,000 BTU. The options include compact indoor units, larger whole-home systems, and one outdoor Rheem model that avoids indoor venting.

Some emphasize precise temperature control, while others add WiFi, freeze protection, self-diagnostics, or hot-start programming. Because listed capacity alone does not determine fit, compare simultaneous shower and fixture demand, installation requirements, dimensions, voltage, venting, and warranty coverage before choosing.

Professional gas, vent, and electrical installation may be necessary depending on the model and local requirements.

The best match depends on demand and installation: choose a 4.2–5 GPM model for lighter use, a 6.8–7.9 GPM unit for broader whole-home demand, or an 8.4–10.3 GPM model for multiple bathrooms. Indoor choices include WiFi control, temperature regulation, freeze protection, and digital displays. The Rheem RTG-70XLN-3 is an outdoor option, while the Rheem RTGH-84DVLN-3 uses indoor direct venting and lists a 0.93 UEF.

Confirm gas, venting, electrical, and local installation compatibility before purchase.

Gas Tankless Water Heater Comparison

Image	Product	Buy
Best Pick 1	APUS Natural Gas Tankless Water Heater, 95,000 BTU, 4.42 GPM Indoor Best for: Compact Indoor Unit Brand: APUS | Capacity: 4.42 gallons	View on Amazon
Best Pick 2	Westinghouse Tankless Water Heater Gas Indoor, 7.9 GPM, 180,000 BTU Best for: High Flow Rate Brand: Westinghouse | Color: Grey 79NI	View on Amazon
Best Pick 3	Rheem RTG Series 7.0 GPM Natural Gas Tankless Water Heater Outdoor | 160,000 BTUs High Efficiency On Demand, Continuous Hot Water | Non-Condensing Best for: Outdoor Installation Brand: Rheem | Capacity: 7 gallons	View on Amazon
Best Pick 4	Rheem RTGH Series 8.4 GPM Natural Gas Tankless Water Heater Indoor | 157,000 BTUs Super High Efficiency On Demand, Continuous Hot Water | Condensing Ultra-Low Nox Best for: Condensing Efficiency Brand: Rheem | Capacity: 8.4 gallons	View on Amazon
Best Pick 5	ThermoMate CZ422NG, Natural Gas Tankless Water Heater Indoor, Up to 5 GPM Best for: Basic Indoor Needs Brand: thermomate | Capacity: 5 gallons	View on Amazon

How We Compared These Products

We compared dimensions, capacity, materials, compatibility, included components, and care requirements across many Amazon listings. These details matter because the product must fit the available space, intended use, setup requirements, and maintenance routine. After examining the wider field, we selected 10 products from APUS, Westinghouse, Rheem, thermomate, GASLAND, MIZUDO, Heatrova, and QERPRE.

The shortlist includes products such as APUS Natural Gas Tankless Water Heater, Westinghouse Tankless Water Heater Gas Indoor, and Rheem RTG Series 7.0 GPM Natural Gas Tankless Water Heater Outdoor. Every recommendation is tied to information stated for that specific product; unclear or missing features were treated as unknown rather than filled with assumptions.

Detailed Reviews: Best Gas Water Heaters Consumer Reports

1. APUS Natural Gas Tankless Water Heater, 95,000 BTU, 4.42 GPM Indoor

Best for: Compact Space Saving.

The APUS Natural Gas Tankless Water Heater offers a compact 5.9"W x 20.55"H design, ideal for smaller spaces. It delivers 4.42 GPM with 95,000 BTU, ensuring hot water for basic household needs while consuming only 35 watts.

This 19.2-pound unit features a 4.42 GPM capacity and 95,000 BTU output, suitable for single-point use or smaller homes. Its compact dimensions of 5.9"W x 20.55"H make installation flexible. Operating on 120 volts and 35 watts, it includes essential components like a vent pipe and assembly kit for straightforward setup.

Product Details

Pros

• Compact dimensions for easy placement
• Provides 4.42 GPM flow rate
• Efficient 35-watt power consumption
• Includes necessary installation components

Cons

• Limited to 4.42 GPM, may not suit high-demand households.

Ideal for apartments or small homes needing a space-saving solution, this heater is best for moderate hot water usage. Consider larger models if multiple fixtures are used simultaneously.

2. Westinghouse Tankless Water Heater Gas Indoor, 7.9 GPM, 180,000 BTU

Best for: Smart Home Integration.

The Westinghouse Tankless Water Heater provides endless hot water for your whole home with a powerful 7.9 GPM and 180,000 BTU output. Its integrated WiFi allows for convenient control via app or voice command, offering smart management of your hot water.

This unit delivers up to 7.9 GPM and 180,000 BTU, capable of supplying hot water to three showers concurrently. Featuring WiFi and app control, you can adjust temperature settings remotely. The cold rolled steel construction ensures durability, and it operates on 120 volts with an LED display for easy monitoring.

Product Details

Pros

• Whole-home hot water supply up to 7.9 GPM
• Smart WiFi and app control
• 180,000 BTU heating capacity
• LED display for easy monitoring

Cons

• Requires 120 volts, ensure compatibility with electrical setup.

Perfect for larger homes with multiple simultaneous hot water needs, this smart heater offers convenience. Ensure your home's electrical system can support its 120-volt operation.

3. Rheem RTG Series 7.0 GPM Natural Gas Tankless Water Heater Outdoor | 160,000 BTUs High Efficiency On Demand, Continuous Hot Water | Non-Condensing

Best for: Outdoor Installation Ready.

The Rheem RTG Series outdoor tankless water heater delivers continuous hot water on demand with 7.0 GPM and 160,000 BTUs. Its non-condensing, high-efficiency design eliminates the need for indoor venting, simplifying installation.

This 39.3-pound unit provides 7.0 GPM at a 35°F temperature rise, suitable for 2-3 simultaneous showers. Its stainless steel construction and outdoor installation capability, with a low activation flow rate and freeze protection, make it versatile.

Product Details

Pros

• Continuous hot water for 2-3 simultaneous showers
• Outdoor installation saves indoor space
• Energy efficient with 0.82 UEF
• Features freeze protection

Cons

• Non-condensing design may be less efficient in colder climates.

Ideal for homes seeking outdoor installation and consistent hot water, this Rheem model is a good fit for moderate climates. Verify outdoor installation suitability for your specific location.

4. Rheem RTGH Series 8.4 GPM Natural Gas Tankless Water Heater Indoor | 157,000 BTUs Super High Efficiency On Demand, Continuous Hot Water | Condensing Ultra-Low Nox

Best for: Ultra-High Efficiency.

The Rheem RTGH Series indoor tankless water heater boasts 8.4 GPM and 157,000 BTUs, featuring industry-leading condensing technology for ultra-low gas bills. Its super high efficiency and 0.93 UEF make it an eco-friendly choice.

With 8.4 GPM at a 35°F rise, this 59.9-pound unit is perfect for 3-4 simultaneous showers. The condensing technology and 0.93 UEF significantly reduce energy consumption. It includes exclusive Hot Start Programming to eliminate cold water bursts and operates on 120 volts with 132 watts.

Product Details

Pros

• Supplies 8.4 GPM for 3-4 simultaneous showers
• Ultra-low NOx emissions
• Industry-leading condensing technology
• Hot Start Programming for instant hot water

Cons

• Requires 132 watts, higher than some other models.

Best for large families or multi-bathroom homes demanding high hot water flow and energy efficiency. Ensure your electrical setup can handle its 132-watt power draw.

5. ThermoMate CZ422NG, Natural Gas Tankless Water Heater Indoor, Up to 5 GPM

Best for: Compact 5 GPM Flow.

The ThermoMate CZ422NG natural gas tankless water heater provides up to 5 GPM, suitable for smaller households or specific point-of-use applications. Its compact design and multiple safety features ensure reliable operation.

This 22-pound unit offers a 5 GPM flow rate, ideal for moderate hot water needs. It operates on 120 volts and includes features like anti-freezing protection, dry combustion protection, and flame failure protection. The 13.77"W x 21.65"H dimensions make it easy to install in various locations.

Product Details

Pros

• Up to 5 GPM flow rate
• Compact size for flexible installation
• Multiple built-in safety features
• Anti-freezing protection included

Cons

• 5 GPM may be insufficient for multiple simultaneous uses.

Suitable for apartments or homes with lower hot water demand, this heater offers reliable performance. It's not recommended for households needing to run multiple high-flow fixtures at once.

6. APUS Natural Gas Tankless Water Heater, 140,000 BTU, Up to 6.8 GPM, Indoor

Best for: Instant Hot Water Tech.

The APUS Natural Gas Tankless Water Heater delivers instant hot water in just 1 second with its 140,000 BTU burner and Zero Cold Water Tech. This 6.8 GPM unit ensures immediate comfort without any cold water wait.

Featuring an oxygen-free copper heat exchanger and 140,000 BTU, this 26.9-pound heater provides 6.8 GPM. Its exclusive single-circulation technology eliminates cold water pockets for truly instant hot water. Operating on 120 volts with 44 watts, it includes a vent pipe and assembly kit for installation.

Product Details

Pros

• Instant hot water in 1 second
• Zero Cold Water Tech eliminates wait
• Durable oxygen-free copper heat exchanger
• Includes installation accessories

Cons

• Requires 120 volts for operation.

Ideal for users prioritizing immediate hot water delivery, this APUS model is great for busy households. Ensure compatibility with its 120-volt requirement.

7. GASLAND Gasmart E 199,000 BTU Tankless Water Heater, Up to 7.6 GPM, CSA Certified Whole House Natural Gas Indoor Installation Residential On-demand Instant Hot Water Heater, CE686NG

Best for: CSA Certified Safety.

The GASLAND Gasmart E tankless water heater offers unlimited hot water on demand with up to 7.6 GPM and 199,000 BTU. CSA certified, it meets high safety standards for reliable residential use.

This 37.5-pound unit provides continuous hot water for showers, laundry, and dishes without interruption. Its iron and copper construction, coupled with features like anti-freezing and flame failure protection, ensures durability and safety. Operating on 120 volts with 52 KW, it's designed for whole-house applications.

Product Details

Pros

• Unlimited hot water on demand
• CSA certified for safety
• Up to 7.6 GPM flow rate
• Multiple safety features included

Cons

• Uses 52 KW, which is a significant power draw.

A strong choice for whole-house hot water needs with a focus on safety, this GASLAND heater is suitable for families. Verify your electrical capacity can handle its 52 KW usage.

8. MIZUDO Natural Gas Tankless Water Heater, 199,000 BTU, Indoor

Best for: High Flow Capacity.

The MIZUDO Natural Gas Tankless Water Heater delivers up to 10.3 GPM with 199,000 BTU, supporting simultaneous hot water demand across multiple bathrooms and appliances. Its precise temperature control maintains water temperature within ±1°F.

This 55.5-pound unit is ideal for busy households, supporting 2-3 bathrooms, kitchen faucets, and laundry. The advanced gas modulation ensures water temperature stability within ±1°F, up to 149°F. It operates on 120 volts with 44 watts and includes comprehensive installation components.

Product Details

Pros

• Exceptional 10.3 GPM flow rate
• Precise ±1°F temperature control
• Supports 2-3 bathrooms simultaneously
• High heating capacity of 199,000 BTU

Cons

• Higher BTU output may require specific gas line sizing.

Best for large homes with high simultaneous hot water demands, this MIZUDO heater offers superior flow and temperature stability. Consult a professional for gas line requirements due to its high BTU.

9. Natural Gas Tankless Water Heater Indoor,HeatRova 4.3 GPM 102,000 BTU,Instant Hot Water,Constant Temperature,Pure Copper Heat Exchanger,3/4″ NPT Connector,Energy-Saving,On-Demand for 3–4 Fixtures

Best for: Constant Temperature Control.

The Heatrova Natural Gas Tankless Water Heater provides instant hot water with a 4.3 GPM flow rate and 102,000 BTU. Its Intelligent Constant Temperature Control ensures consistent water temperature for up to 3-4 fixtures simultaneously.

This unit is designed for larger homes, offering 4.3 GPM and 102,000 BTU to supply endless hot water for showers and kitchens. The Constant Temperature PLUS technology maintains a stable output, preventing temperature fluctuations. It features a pure copper heat exchanger and a 3/4" NPT connector.

Product Details

Pros

• Maintains constant water temperature
• Suitable for 3-4 fixtures
• Pure copper heat exchanger
• Energy-saving design

Cons

• 4.3 GPM may be limited for very high-demand scenarios.

Ideal for homes needing consistent temperature across multiple fixtures, this Heatrova model is a solid choice. It's best suited for moderate simultaneous usage, not extreme demand.

10. Tankless Water Heater Natural Gas, Indoor Max 4.3 GPM, 100,000 BTU, Instant Hot Water Heater for Home, Apartment, Commercial Setting, Vent Pipe Included, within 1°F Stable Temp, LED Digital Display

Best for: LED Display & Temp Lock.

The QERPRE Tankless Water Heater delivers instant hot water with a 4.3 GPM flow rate and 100,000 BTU, suitable for home, apartment, or commercial settings. Its LED digital display and temperature lock feature offer user-friendly control.

This gray unit provides 4.3 GPM and 100,000 BTU, ensuring on-demand hot water. The temperature lock feature, combined with an LED display, allows for precise and easy temperature management. It includes anti-freezing and dry combustion protection, operating on 110 volts.

Product Details

Pros

• LED digital display for easy control
• Temperature lock feature
• Suitable for various settings
• Includes anti-freezing protection

Cons

• Operates on 110 volts, potentially lower power than 120V models.

A good option for apartments or smaller commercial spaces seeking an easy-to-use heater with temperature control. Ensure its 110-volt operation meets your power needs.

What Buyers Often Overlook

How to size a gas tankless water heater for simultaneous demand

Size the heater by the total flow required when fixtures run together, not by the advertised capacity label alone. The products span 4.2, 4.3, 5, 6.8, 7.0, 7.6, 7.9, 8.4, and 10.3 GPM. The APUS 4.42 GPM, Heatrova 4.3 GPM, and QERPRE 4.3 GPM models suit lighter simultaneous demand, while ThermoMate’s 5 GPM unit provides a modest step up.

APUS’s 6.8 GPM model, Rheem’s 7.0 GPM outdoor model, GASLAND’s 7.6 GPM unit, and Westinghouse’s 7.9 GPM model target broader household use. Rheem’s 8.4 GPM model is described for three to four simultaneous showers, and MIZUDO lists up to 10.3 GPM for demand across two to three bathrooms and other fixtures.

Actual performance varies with incoming water temperature and fixture flow, so use peak demand rather than household size alone.

The Key Product Trade-Off

Indoor versus outdoor installation and feature trade-offs

Installation location is a primary compatibility decision: the Rheem RTG-70XLN-3 is designed for outdoor installation and states that outdoor placement eliminates venting, while the other listed options are indoor models. Indoor systems require attention to venting, clearances, gas connections, and available 120-volt or 110-volt electrical service as specified. The Rheem RTGH-84DVLN-3 uses direct venting, lists a stainless-steel construction, and includes freeze protection, electric ignition, and hot-start programming.

Westinghouse adds WiFi and app or voice control, with an LED display and overheat protection. ThermoMate, GASLAND, and Heatrova list anti-freezing, dry-combustion, flame-failure, or high-water-pressure protections.

Condensing and non-condensing designs are not interchangeable installation choices, so verify venting instructions and local requirements before selecting a replacement.

Best Gas Water Heaters Consumer Reports: Buyer's Guide

Fit, Dimensions, and Compatibility

Compare the listed dimensions with the intended counter, cabinet, appliance, storage, or installation space. Confirm model compatibility and connection requirements where they are supplied. A useful feature cannot compensate for a product that does not physically fit or work with the buyer’s existing setup.

Capacity, Output, and Operating Format

Match listed capacity, volume, output, and operating mode to the actual household or work routine. Larger figures can support heavier use, while a smaller format may be easier to place and maintain. Treat daily output, immediate storage, and container capacity as separate specifications when the listing distinguishes them.

Materials, Construction, and Care

Use the listed materials and care instructions to judge cleaning effort, storage conditions, and compatibility with the intended use. Dishwasher, freezer, food-contact, or weather-related claims are included only when supplied for that product. Check whether routine care fits the way the product will be used.

Included Components and Setup Needs

Review the included components before planning installation or first use. Hoses, adapters, lids, paddles, bowls, brushes, controls, and manuals vary by listing. Confirm power, water, assembly, or accessory requirements from the supplied product information rather than assuming that separately pictured parts are included.

Which Should You Choose?

Choose a compact lower-flow indoor model when space and lighter demand are priorities: APUS’s 4.42 GPM unit is only 5.9 inches wide, while Heatrova and QERPRE offer 4.3 GPM indoor options with temperature-control or display features. For a typical whole-home upgrade, consider APUS at 6.8 GPM, Rheem at 7.0 GPM outdoors, GASLAND at 7.6 GPM, or Westinghouse at 7.9 GPM with WiFi control. Larger households should compare Rheem’s 8.4 GPM condensing model and MIZUDO’s listed 10.3 GPM capacity.

Select ThermoMate for a 5 GPM middle ground and prioritize its listed protection features where installation conditions are a concern. Confirm dimensions, venting, gas supply, voltage, and required professional installation before ordering.

Quick Buying Checklist

• Confirm the complete dimensions against the available space.
• Verify model, accessory, connection, and appliance compatibility.
• Match capacity or output to the expected amount of use.
• Compare materials and care instructions with the maintenance routine.
• Check the included components before planning setup or first use.
• Confirm listed power, water, storage, or installation requirements where applicable.

Frequently Asked Questions

What is the typical lifespan of a gas tankless water heater?

Gas tankless water heaters generally last between 15 to 20 years with proper maintenance. Regular flushing and inspections can help extend their operational life. Ensure the unit is installed correctly and in a suitable environment to prevent premature wear and tear.

How do I choose the right GPM for my needs?

GPM, or gallons per minute, indicates how much hot water the heater can supply simultaneously. Consider the number of fixtures you’ll use at once. For 2-3 simultaneous uses, aim for 5-7 GPM.

Higher GPM is needed for more demanding households or simultaneous high-flow appliances.

What are the venting requirements for gas tankless water heaters?

Venting requirements vary by model and installation type (indoor/outdoor). Most indoor units require direct or power venting through an exterior wall. Consult the manufacturer’s manual for specific vent pipe material, diameter, and routing guidelines to ensure safe operation and prevent carbon monoxide buildup.

Can a tankless water heater handle multiple showers at once?

Yes, a properly sized tankless water heater can handle multiple showers simultaneously. The key is selecting a unit with a sufficient GPM rating. For example, if each shower uses 2.5 GPM, a 5 GPM unit could theoretically run two showers, while a higher GPM unit could support more.

What maintenance is required for a gas tankless water heater?

Regular maintenance typically involves flushing the unit annually to remove mineral buildup, especially in hard water areas. Inspecting the vent system for obstructions and checking the gas and water connections are also important. Some models may require periodic filter cleaning.

Final Words

Selecting the best gas tankless water heater depends on your specific hot water demands and installation environment. For high-demand households, units with higher GPM and BTU ratings are essential. Consider factors like indoor/outdoor installation and condensing versus non-condensing models for optimal efficiency and longevity.