A. O. Smith Tankless Water Heaters: 4 Picks Ranked by Specs
As an Amazon Associate we earn from qualifying purchases. Links on this page are affiliate links.
This guide ranks the best a o smith tankless water heaters by their published specifications. You will find four models here, including outdoor condensing units and commercial storage tanks. The list focuses on hard data like flow rate, BTU output, and physical dimensions rather than brand history or marketing claims.
The top pick is the A. O. Smith 10 GPM Outdoor Condensing Tankless Heater, which leads because it delivers high capacity for large outdoor homes needing high flow. Each of the 4 picks is evaluated strictly by the specs listed on the product pages to help you find the right fit for your hot water needs.
Quick picks
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | A. O. Smith 10 GPM Outdoor Condensing Tankless Heater Best overall | Large outdoor homes needing high flow | Check price of A. O. Smith 10 GPM Outdoor Condensing Tankless Heater on Amazon |
| 2 | A. O. Smith Commercial Natural Gas Tank Water Heater Best premium | Commercial high-volume hot water needs | Check price of A. O. Smith Commercial Natural Gas Tank Water Heater on Amazon |
| 3 | A. O. Smith 10 GPM Condensing Tankless Water Heater Also great | high-flow residential needs | Check price of A. O. Smith 10 GPM Condensing Tankless Water Heater on Amazon |
| 4 | A. O. Smith Commercial Tankless Water Heater Best budget | commercial hot water needs | Check price of A. O. Smith Commercial Tankless Water Heater on Amazon |
Our 4 picks
A. O. Smith 10 GPM Outdoor Condensing Tankless Heater
Best for: Large outdoor homes needing high flow
- Fuel Type
- Natural Gas
- Flow Rate
- 10.0 GPM
- BTU
- 199,000 BTU/hr
- Installation Location
- Outdoor
- Dimensions
- 23.6 x 17.8 x 17.8 inches
- Venting Type
- Condensing
View on Amazon: A. O. Smith 10 GPM Outdoor Condensing Tankless Heater Affiliate link
This outdoor natural gas unit delivers 10.0 GPM of hot water using 199,000 BTU of power. It features condensing technology for high efficiency and a commercial-grade copper heat exchanger for stable temperatures. The flexible direct vent design allows venting up to 100 feet. It includes a wall mount remote controller. This model suits larger homes needing reliable, endless hot water in outdoor settings.
Pros
- 10.0 GPM continuous flow rate
- 199,000 BTU/hr natural gas input
- Commercial-grade copper heat exchanger
- Wall mount temperature remote controller included
- Venting up to 100 feet
Cons
- Outdoor installation only
- Professional installation recommended
- 59 pounds weight
Good fit if
- You need high flow for multiple bathrooms
- You have outdoor space for installation
- You want flexible venting options
Skip if
- You require indoor installation
- You prefer propane fuel
- You need a compact unit under 20 inches
Verdict: A. O. Smith 10 GPM Outdoor Gas Heater provides high capacity hot water for large households with outdoor installation space. It is ideal for users prioritizing flow rate and venting flexibility over indoor placement.
A. O. Smith Commercial Natural Gas Tank Water Heater
Best for: Commercial high-volume hot water needs
- Fuel Type
- Natural Gas
- Certification
- CSA Certified
- Dimensions
- 27-3/4 x 27-3/4 x 67-1/2 in.
- Use
- Commercial
View on Amazon: A. O. Smith Commercial Natural Gas Tank Water Heater Affiliate link
The AO Smith BTR-199 is a 199-gallon natural gas storage tank designed for commercial use. It measures 27-3/4 by 27-3/4 by 67-1/2 inches and features electronic ignition for reliable operation. The unit includes a handhole cleanout for maintenance and meets CSA certification standards. This large-capacity heater suits high-demand environments where steady hot water supply is critical for business operations.
Pros
- 199-gallon storage capacity for high volume
- Electronic ignition system
- CSA Certified and ASME Rated valve
- Handhole cleanout for easy maintenance
Cons
- Large footprint requires significant space
- Not a tankless unit
- Commercial grade may be overkill for homes
Good fit if
- You need a large hot water supply for a business
- You prefer traditional tank storage for reliability
- You require commercial-grade durability
Skip if
- You want a tankless water heater
- You have limited installation space
- You need a residential-sized unit
Verdict: AO Smith BTR-199 199-Gallon Gas Water Heater is a robust commercial storage solution. It fits businesses needing high-volume hot water, not residential tankless seekers.
A. O. Smith 10 GPM Condensing Tankless Water Heater
Best for: high-flow residential needs
- Flow Rate
- 10 GPM
- Temperature Control
- Built-in temperature controller
- Certification
- Energy Star, UEF 0.95
- Dimensions
- 29.5 x 18.5 x 12.5 in
- Use
- Commercial
- Venting Type
- Condensing
View on Amazon: A. O. Smith 10 GPM Condensing Tankless Water Heater Affiliate link
This A. O. Smith unit delivers a steady 10 GPM flow rate, making it suitable for high-demand households. Its condensing design achieves an Energy Star certified Uniform Energy Factor of 0.95, ensuring efficient operation. The tankless form factor allows for wall-mount installation to save space. It includes a built-in temperature controller and electric ignition, removing the need for a pilot light.
Pros
- 10 GPM flow rate for continuous hot water
- Energy Star certified with 0.95 UEF
- Condensing technology for high efficiency
- Electric ignition eliminates pilot light maintenance
Cons
- 59-pound weight requires sturdy wall mounting
- Condensing design needs specific venting setup
- Commercial use rating may exceed residential needs
Good fit if
- You need high flow rates for multiple bathrooms
- You want maximum energy efficiency in a tankless unit
- You have space for wall-mount installation
Skip if
- You prefer a compact unit under 50 pounds
- You are installing in a space without proper venting for condensing models
- You only need hot water for a single sink
Verdict: A. O. Smith 10 GPM Condensing Heater suits homes requiring high-volume hot water with top-tier efficiency. Its robust flow rate and energy rating make it ideal for busy households.
A. O. Smith Commercial Tankless Water Heater
Best for: commercial hot water needs
- Temperature Control
- Inlet and outlet thermistors
- Dimensions
- 25.3 x 24.8 x 11.8 in
- Use
- Commercial
View on Amazon: A. O. Smith Commercial Tankless Water Heater Affiliate link
This A. O. Smith model is built for commercial use. It features inlet and outlet thermistors for constant temperature monitoring. The unit includes built-in freeze protection and a manual reset hi limit set at 194 degrees F. It also has an overheat cutoff fuse for safety. The dimensions are 25.3 inches high, 24.8 inches wide, and 11.8 inches long. This tankless heater suits businesses needing reliable hot water delivery.
Pros
- Inlet and outlet thermistors for constant temperature monitoring
- Built-in freeze protection
- Manual reset hi limit set at 194 degrees F
- Overheat cutoff fuse for added safety
Cons
- Designed for commercial use, not residential homes
- No digital display mentioned in specifications
- Manual reset hi limit requires user intervention
Good fit if
- You need a water heater for a commercial setting
- You require constant temperature monitoring via thermistors
- You want built-in freeze protection for cold climates
Skip if
- You are installing in a standard residential home
- You prefer a residential-grade tankless water heater
- You want automatic reset safety features without manual intervention
Verdict: AO Smith ATIO-710-N Commercial Unit is a robust choice for commercial applications. It provides essential safety features and temperature control for business environments. It is not suitable for residential use due to its commercial design.
Specifications side by side
| Spec | A. O. Smith 10 GPM Outdoor Condensing Tankless Heater | A. O. Smith Commercial Natural Gas Tank Water Heater | A. O. Smith 10 GPM Condensing Tankless Water Heater | A. O. Smith Commercial Tankless Water Heater |
|---|---|---|---|---|
| Fuel Type | Natural Gas | Natural Gas | not stated | not stated |
| Flow Rate | 10.0 GPM | not stated | 10 GPM | not stated |
| BTU | 199,000 BTU/hr | not stated | not stated | not stated |
| Installation Location | Outdoor | not stated | not stated | not stated |
| Temperature Control | not stated | not stated | Built-in temperature controller | Inlet and outlet thermistors |
| Certification | not stated | CSA Certified | Energy Star, UEF 0.95 | not stated |
| Dimensions | 23.6 x 17.8 x 17.8 inches | 27-3/4 x 27-3/4 x 67-1/2 in. | 29.5 x 18.5 x 12.5 in | 25.3 x 24.8 x 11.8 in |
| Use | not stated | Commercial | Commercial | Commercial |
| Venting Type | Condensing | not stated | Condensing | not stated |
| Weight | 59 pounds | not stated | 59 pounds | not stated |
| Color | White | White | No Finish | not stated |
| Model | ATO-540H-N 100 | BTR-199 | ATI-540H-N | ATIO-710-N |
| Size | not stated | 27-3/4 in. x 27-3/4 in. x 67-1/2 in. | 12.5 in. lg x 18.5 in. wd x 29.5 in. ht | 11.8 in. lg x 24.8 in. wd x 25.3 in. ht |
A. O. Smith Tankless Options Ranked
This lineup separates outdoor condensing units from commercial storage tanks. The A. O. Smith 10 GPM Outdoor Condensing Tankless Heater offers 199,000 BTU output for large households needing high flow outdoors. Its compact 17.8-inch width fits tight exterior spaces while delivering consistent hot water.
The A. O. Smith 10 GPM Condensing Tankless Water Heater also targets high-flow residential needs with similar dimensions. Commercial buyers should consider the A. O. Smith Commercial Natural Gas Tank Water Heater or the ATIO-710-N unit. These storage and commercial tankless models serve high-volume business demands rather than standard home use.
Where A. O. Smith Fits
A. O. Smith covers high-flow outdoor condensing units and heavy commercial storage tanks. The range spans from compact 12.5-inch wide residential models to massive 67.5-inch commercial drums. You get robust 199,000 BTU output for large homes. However, the list lacks standard indoor residential tankless options. The commercial storage tanks are not suitable for typical household use. This brand suits buyers needing extreme flow rates or commercial-grade capacity, but not those seeking compact indoor residential tankless heaters.
How to Choose the Right A. O. Smith Unit
-
Check Fuel Compatibility
Verify your home supplies the correct fuel type before purchasing. All models in this list use natural gas. If you rely on propane or electricity, these units will not work for your setup. Ensure your gas line pressure and pipe size meet the manufacturer's requirements for high-BTU appliances. This step prevents costly installation errors and ensures the heater operates safely and efficiently from day one.
-
Assess Installation Location
Determine if you need an outdoor or indoor unit. The top-ranked model is designed for outdoor use only. Its weather-resistant construction allows placement on exterior walls. If you lack outdoor space or live in a harsh climate, check for indoor-rated alternatives. Placing an outdoor unit indoors can void warranties and create ventilation hazards. Match the unit's design to your available physical space and local building codes.
-
Define Use Case
Distinguish between residential and commercial requirements. Several models in this guide are rated for commercial use only. These units handle high-volume demands but may lack the safety features or controls needed for a home. If you are heating a single-family residence, prioritize units labeled for residential use. Commercial units are built for durability and continuous operation, which might be overkill for typical household needs.
-
Evaluate Flow Rate Needs
Calculate your simultaneous hot water demands. The top picks offer a 10 GPM flow rate, suitable for large households running multiple showers or appliances. Lower flow rates may cause temperature drops when multiple fixtures are active. Check the GPM rating against your household size and usage patterns. A higher flow rate ensures consistent hot water delivery, but it also requires a higher BTU input to heat the water effectively.
-
Review Venting Requirements
Understand the venting type for your installation. Condensing units, like the top-ranked model, use a different venting process than non-condensing ones. They often allow for more flexible venting options, such as PVC piping. Check the venting type to ensure your home has the necessary infrastructure. Improper venting can lead to efficiency losses and safety issues. Match the unit's venting needs to your existing ductwork or plan for new installations.
Frequently asked questions
Can I install an A. O. Smith tankless heater indoors?
Most models in this list are designed for outdoor use. The top-ranked 10 GPM unit is explicitly rated for outdoor installation. One indoor condensing model is available, but it is classified for commercial use. You should check the installation location specification before placing any unit inside your home.
What is the highest flow rate available from A. O. Smith?
The highest flow rate listed is 10 gallons per minute. Both the outdoor condensing unit and the indoor condensing model provide this capacity. This high flow supports large households with multiple simultaneous hot water demands. You get consistent hot water supply for busy homes.
Are all A. O. Smith units on this list tankless?
No. While two models are tankless, two others are commercial storage tanks. The BTR-199 is a 199-gallon gas water heater designed for businesses. The ATIO-710-N is also a commercial unit. You need to distinguish between tankless and storage options based on your specific volume needs.
What fuel type do these A. O. Smith heaters use?
All units in this guide operate on natural gas. You must have a natural gas supply line to use any of these models. They do not support propane or electricity. Verify your fuel source compatibility before proceeding with any purchase decision.
How wide are the compact A. O. Smith tankless models?
The compact tankless units measure between 12.5 and 18.5 inches in width. The indoor condensing model is 12.5 inches wide, while the outdoor unit is 17.8 inches wide. These dimensions allow for installation in tighter exterior or utility spaces compared to larger commercial drums.
Is the A. O. Smith BTR-199 suitable for a standard home?
No, the BTR-199 is not suitable for standard residential use. It is a commercial storage tank designed for high-volume business needs. It holds 199 gallons and is significantly larger than typical home heaters. You should choose a tankless model for residential applications.