Best A. O. Smith Tankless Water Heater

Imagine stepping into the shower on a chilly morning, only to be met with a blast of cold water because your tank water heater is out of hot water. This frustrating scenario is all too common for homeowners relying on traditional water heaters. Tankless water heaters, however, provide a continuous supply of hot water, eliminating those anxiety-inducing moments. With their increasing popularity, choosing the right model has never been more crucial.

A good tankless water heater combines efficiency, capacity, durability, and safety features. The best models can support multiple fixtures simultaneously, ideal for larger families or homes with multiple bathrooms. Reliability and ease of maintenance are also important factors to consider when selecting a unit.

In this roundup, we’ll explore five top-rated A. O. Smith tankless water heaters, highlighting their unique features, performance, and best use cases. Each option has been carefully evaluated to ensure that you find the perfect fit for your needs.

Here’s a quick comparison of our picks:

Features	A. O. Smith	Rheem 7.0 GPM	Rheem 7.0 GPM	Westinghouse 11kW	Rinnai RX199iN
Material & Build	Marine-grade stainless steel	Metal cabinet	Metal cabinet	ETL certified	Compact design
Key Specification	10 GPM, 199K BTU	7.0 GPM, 160K BTU	7.0 GPM, 160K BTU	2.6 GPM, 11kW	11.1 GPM, 199K BTU
Main Feature	Integrated recirculation pump	Outdoor installation	Indoor installation	Smart WiFi compatible	Versatile installation options
Performance	Continuous hot water	Endless hot water	Endless hot water	Instant heating	Compact yet powerful
Best Use Case	3-4 bathroom homes	Medium households	Medium households	Single point use	High demand households

A. O. Smith Water Heater…

The A. O. Smith ATI-540P-N is designed for larger homes, particularly those with up to four bathrooms. Its continuous flow rate of 10 gallons per minute (GPM) ensures that multiple fixtures can be used simultaneously without a drop in temperature. This makes it ideal for families who often run multiple showers or appliances at the same time.

One standout feature of this unit is its integrated hot water recirculation pump. This allows for almost instantaneous hot water, eliminating the waiting time typical with traditional systems. The materials used in its construction are commercial-grade, providing peace of mind regarding durability and longevity—backed by a 15-year warranty on the heat exchanger.

However, the installation process can be complex, and it’s recommended that a licensed plumber handles it. Additionally, while the initial investment may be higher than traditional tank heaters, the long-term energy savings can offset these costs.

• Continuous flow rate: 10 GPM
• 199,000 BTU output
• Integrated recirculation pump
• 15-year heat exchanger warranty
• Safety features: overheat cut-off fuse

Best for: Large families needing constant hot water.

Rheem RTG Series 7.0 GPM…

The Rheem RTG Series offers a reliable option for homeowners looking to upgrade to a tankless water heater. It provides an impressive 7 GPM at a 35°F temperature rise, making it suitable for medium-sized homes with multiple bathrooms. This model works well for families who want to ensure hot water availability for simultaneous showers.

This liquid propane tankless water heater is known for its energy efficiency, boasting a Uniform Energy Factor (UEF) of 0.82. This means it can save homeowners up to 34% on energy costs compared to traditional electric tank heaters. Its outdoor installation design simplifies the venting process, making it easier to set up.

One limitation is that it may not provide enough hot water for larger households with high simultaneous demand. Plus, homeowners will need to account for professional installation costs, which can add to the overall expense.

• 7.0 GPM flow rate
• 160,000 BTU/hr output
• Energy-efficient non-condensing
• 15-year heat exchanger warranty
• CSA certified with safety features

Best for: Medium households with moderate hot water needs.

Rheem RTG Series 7.0 GPM…

This Rheem RTG Series model is tailored for natural gas, offering similar performance metrics as the propane version. It delivers 7 GPM at a 35°F temperature rise, ensuring that you won’t run out of hot water even during peak usage times. Families with multiple bathrooms will find this model fitting for their needs.

Its non-condensing design still maintains a good UEF of 0.82, making it an efficient choice for homeowners looking to reduce energy expenses. The indoor installation feature allows for easy integration into existing home layouts, while the wall-mounted design saves valuable floor space.

One drawback is the upfront cost associated with professional installation, as well as the fact that it may require more maintenance than a traditional tank system. Understanding local codes and regulations is essential for a successful installation.

• 7.0 GPM flow rate
• 160,000 BTU/hr output
• Indoor installation with direct vent
• 15-year heat exchanger warranty
• LeakGuard leak detection

Best for: Households looking for efficient indoor hot water solutions.

Westinghouse 11kW Tankless…

The Westinghouse 11kW tankless water heater is compact and perfect for smaller applications, such as apartments or vacation homes. It provides up to 2.6 GPM of hot water, making it ideal for single-point use, such as a shower or sink. Its space-saving design is particularly advantageous for those with limited installation options.

One of its standout features is the smart WiFi compatibility. Homeowners can control the unit remotely using voice commands through Alexa or Google Home, enhancing convenience. Additionally, the unit has a temperature memory function, which restores your last setting after a power outage.

However, its 2.6 GPM capacity means it may not satisfy larger households needing hot water for multiple fixtures simultaneously. Also, the requirement for a dedicated 60A breaker could complicate installation for some users.

• Max flow rate: 2.6 GPM
• Smart WiFi compatibility
• ETL certified
• Temperature memory function
• 4-layer safety protection

Best for: Smaller homes or single-point applications.

Rinnai RX199iN Condensing…

The Rinnai RX199iN is a versatile model that can be installed both indoors and outdoors, providing flexibility depending on your home’s layout. It has a robust output of 11.1 GPM, making it suitable for large families or homes with high hot water demands. This unit can support multiple fixtures being used at once without compromising temperature.

This model’s Smart Sense technology allows it to efficiently manage gas usage, promoting energy savings without sacrificing performance. The compact design means it can fit in tight spaces, and it even includes a Quick Flush feature for simplified maintenance.

Despite its many benefits, professional installation is recommended, and the upfront costs can be higher than standard tank systems. Homeowners should also ensure compatibility with their existing plumbing and gas lines before purchasing.

• 11.1 GPM flow rate
• 199,000 BTU output
• Smart Sense gas control
• Quick Flush feature
• Versatile installation options

Best for: Large households needing high demand hot water.

How We Chose These Products

We evaluated these A. O. Smith tankless water heaters based on real-world performance, user feedback, and energy efficiency. Key factors included flow rate, BTU output, installation requirements, and warranty coverage. We also considered how well each model meets the needs of different household sizes and configurations.

Our selection process included a thorough analysis of customer reviews and professional assessments to ensure that we only recommend models that have proven reliability and performance. We focused on products that offer a balance of efficiency, durability, and safety features.

Buying Guide: What Really Matters

When shopping for a tankless water heater, consider the flow rate you need based on your household’s hot water usage. A good rule of thumb is to calculate the GPM required for simultaneous fixtures. Also, consider the BTU output; higher BTUs typically mean faster heating capabilities.

Installation location matters too. Some units are designed for indoor use, while others can be installed outdoors. Ensure that your chosen model fits within your home’s plumbing and electrical configurations. Lastly, look for warranties and customer service reputation, as these can significantly influence your long-term satisfaction.

Our Top Recommendation

The A. O. Smith Water Heater ATI-540P-N stands out as the best choice for families with high hot water demands. Its combination of durability, flow rate, and integrated features makes it a reliable investment. For those with smaller households or specific needs, the Westinghouse 11kW Electric Tankless Water Heater offers the best in compact efficiency.

Frequently Asked Questions

What size tankless water heater do I need? The size depends on your household’s hot water needs. Calculate your peak usage by adding the GPM of fixtures used simultaneously.

How long do tankless water heaters last? Most tankless water heaters have a lifespan of 15 to 20 years with proper maintenance, significantly longer than traditional tank models.

Do I need a special vent for tankless water heaters? Yes, depending on the model, venting requirements vary. Gas models typically require a specific type of venting system to operate safely.

Can I install a tankless water heater myself? While some homeowners may attempt a DIY installation, professional installation is recommended to ensure compliance with local codes and safety standards.