A. O. Smith Tankless Water Heater Natural Review: Specs, Pros and Cons
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This a o smith tankless water heater natural review focuses on the A. O. Smith 10 GPM Outdoor Condensing Tankless Heater. It is a high-capacity unit designed for outdoor use. The listing highlights two defining specifications: a flow rate of up to 10.0 gallons per minute and a heating power of 199,000 BTU per hour. These numbers indicate it can handle significant hot water demand. The unit uses natural gas and features condensing technology for efficiency. It weighs 59 pounds and measures 23.6 by 17.8 by 17.8 inches. This model targets homes with multiple bathrooms needing simultaneous hot water access.
What stands out
- Delivers up to 10.0 GPM of continuous hot water
- 199,000 BTU/hr heating capacity for fast recovery
- Energy Star rated with up to .94 UEF
- Commercial-grade copper heat exchanger for better heat transfer
- Flexible direct venting up to 100 feet with various pipe types
Who it fits
Good fit for
You should consider this unit if you have a large home with three to four bathrooms. The 10 GPM flow rate supports multiple showers running at once in southern climates. It suits outdoor installations where direct venting is feasible. The copper heat exchanger offers durability for residential use. If you need high output and have the space for an outdoor unit, this spec-heavy model fits your needs.
Who should skip it
Skip this option if you need an indoor unit. This model is rated strictly for outdoor installation. You also should look elsewhere if you require propane, as this is natural gas only. The compact indoor variants in the series may suit tight spaces better. Additionally, if you cannot run a direct vent line up to 100 feet, this flexible venting feature will not help your specific setup.
Verdict: This is a powerful outdoor tankless heater built for high-demand households. Its 10 GPM capacity and copper heat exchanger make it a strong choice for multi-bathroom homes with outdoor installation options.
Key specs for this unit
Flow Rate: 10.0 GPM
This rating indicates the maximum volume of hot water the unit delivers each minute. You can run multiple showers or appliances simultaneously without a drop in pressure. This capacity suits larger households with three to four bathrooms. Smaller units often cap at 4 or 6 GPM, which may cause delays when demand is high. Check this number to ensure your home’s plumbing needs are met.
BTU: 199,000 BTU/hr
This figure measures the heating power of the natural gas burner. Higher BTU input allows the heater to raise water temperature quickly, even in cold climates. It supports the high flow rate by providing enough thermal energy. Compare this against lower-output models if you live in a region with very cold incoming groundwater. It ensures consistent performance during peak usage times.
Fuel Type: Natural Gas
This unit requires a connection to your home’s natural gas line. It is not compatible with propane unless specifically converted, which is not listed here. Natural gas typically offers lower operating costs and a steady fuel supply compared to propane tanks. Verify your home has a gas line before purchasing. This fuel type is standard for most suburban homes and simplifies installation if infrastructure is already in place.
Installation Location: Outdoor
This heater is designed to be mounted outside your home. It requires a weather-resistant setup and proper clearance for ventilation. You cannot install it in an enclosed indoor space without specific venting modifications, which are not included. This saves indoor space and avoids the need for complex indoor exhaust systems. Ensure you have an exterior wall with access to gas and drainage before buying.
Venting Type: Condensing
Condensing technology extracts heat from exhaust gases, improving efficiency. It allows the use of plastic vent pipes like PVC or CPVC, which are easier to install than metal flues. This design reduces energy waste and lowers your utility bills. It is ideal for outdoor installations where venting length can extend up to 100 feet. Compare this with non-condensing models that often require expensive metal venting.
Design and Build Analysis
According to the listing, this unit measures 23.6 inches in height, with a width and length of 17.8 inches each. The white finish is standard for outdoor equipment, helping it blend into exterior walls without drawing attention. The unit weighs 59 pounds, which is moderate for a high-output tankless heater. You will need a sturdy wall mount to support this weight safely during operation.
The device features a commercial-grade copper heat exchanger. Copper provides better heat transfer than steel, which helps maintain stable water temperatures under heavy load. This material choice supports the unit’s 199,000 BTU/hr output. The condensing design allows for flexible venting options. You can use PVC, CPVC, polypropylene, or ABS pipe for up to 100 feet of direct venting. This layout simplifies installation in various outdoor configurations.
Control is managed via a wall-mounted temperature remote controller. This placement keeps the main interface away from the unit itself, allowing you to adjust settings without interacting with the hardware directly. Advanced diagnostics are included to help monitor performance. The compact footprint and remote control design make this unit suitable for tight outdoor spaces where access might be limited. The outdoor-specific construction ensures durability against weather exposure.
Installation and Daily Operation Guide
Setting up this unit requires professional installation due to its high output and outdoor placement. The flexible direct vent design allows you to route exhaust pipes up to 100 feet. You can use PVC, CPVC, polypropylene, or ABS solid core pipe for venting. This flexibility helps you position the unit where it fits best on your exterior wall. The unit includes a wall mount temperature remote controller. This lets you adjust the water temperature from a distance, which is useful if the heater is mounted high or in a hard-to-reach spot. The advanced diagnostics feature helps you monitor the system status easily. In daily use, the 10.0 GPM flow rate supports continuous hot water for multiple bathrooms. The condensing technology ensures efficient heating, delivering up to 0.94 UEF. This efficiency helps reduce energy usage while maintaining steady performance. The commercial-grade copper heat exchanger provides stable water temperatures by transferring heat 25 times better than steel. Safety features like exhaust and water temperature controls, an overheat cut-off fuse, and an air-fuel ratio sensor are built in to protect your home. These components work together to prevent overheating and ensure safe operation. You do not need to worry about manual adjustments during use, as the unit manages temperature and safety automatically. The 15-year limited warranty on the heat exchanger offers long-term peace of mind for residential applications. Overall, the setup is straightforward with professional help, and daily operation is reliable and efficient.
Before You Buy This Unit
This A. O. Smith model delivers 10.0 GPM, making it suitable for homes with three to four bathrooms. You must ensure your gas line can support 199,000 BTU/hr input. Check your local codes for outdoor venting requirements, as the unit uses a direct vent design. You can route exhaust pipes up to 100 feet using PVC, CPVC, polypropylene, or ABS solid core pipe. The unit includes a wall mount temperature remote controller, so verify you have a suitable location for it. Professional installation is recommended due to the high capacity. This condensing technology offers high efficiency, but you should compare its UEF against other high-flow options. If you need a smaller unit for a single bathroom, consider lower GPM models. This heater fits best in northern climates for three baths or southern climates for four. Ensure your outdoor space can accommodate its 23.6-inch height and 59-pound weight.
Check before you buy
- Confirm gas line capacity supports 199,000 BTU/hr input.
- Check local codes for outdoor direct vent placement.
- Verify space for 23.6-inch height and 59-pound weight.
- Plan remote controller location within reach.
The product at a glance
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 up to 10.0 GPM with 199,000 BTU/hr of power. It uses condensing technology for high efficiency and includes a wall-mounted remote controller. The copper heat exchanger offers strong heat transfer. It suits homes with three to four bathrooms in northern or southern climates. Professional installation is recommended for this direct vent system.
Pros
- 10.0 GPM flow rate for multiple fixtures
- 199,000 BTU/hr heating capacity
- Commercial-grade copper heat exchanger
- Includes wall mount temperature remote
- Direct vent up to 100 feet
Cons
- Outdoor installation only
- 59 pounds weight requires sturdy mounting
- Professional installation recommended
Good fit if
- You need high flow for three or four bathrooms
- You have an outdoor wall for direct venting
- You want a copper heat exchanger for durability
Skip if
- You need an indoor unit
- You require propane fuel
- You want a DIY-friendly setup
Verdict: A. O. Smith 10 GPM Outdoor Natural Gas provides robust hot water for large homes with outdoor venting space. It fits buyers needing high capacity and durable copper components.
Specifications side by side
| Spec | A. O. Smith 10 GPM Outdoor Condensing Tankless Heater |
|---|---|
| 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 |
| Weight | 59 pounds |
| Color | White |
| Model | ATO-540H-N 100 |
Frequently asked questions
Can this A. O. Smith tankless heater be installed indoors?
No, this unit is designed strictly for outdoor installation. The listing specifies it as an outdoor condensing tankless heater. Indoor installation requires different venting and safety clearances that this model does not support. You must place it outside on a solid surface.
What fuel type does this model use?
It uses natural gas as its fuel source. The unit requires a connection to a natural gas line. You cannot use propane with this specific model unless it is converted by a professional, though the data lists natural gas as the primary fuel type.
How much space does the heater take up?
The unit measures 17.8 inches in width and length, with a height of 23.6 inches. It weighs 59 pounds. You need a clear area for installation that accommodates these dimensions. Ensure you have enough wall space for the white finish and venting connections.
Is the venting system flexible for different home layouts?
Yes, the condensing design offers flexible venting options. You can route exhaust pipes up to 100 feet. This allows you to adapt the unit to various outdoor wall configurations. The system supports multiple pipe materials for durable and efficient exhaust removal.
What is the maximum hot water output?
The heater provides a flow rate of up to 10.0 gallons per minute. This high output supports multiple simultaneous uses, such as showers and kitchen sinks. It is suitable for large homes needing consistent hot water supply during peak usage times.
Does it require professional installation?
Yes, professional installation is required due to its high capacity and outdoor placement. The unit connects to natural gas and requires proper venting. A certified technician ensures safe gas line connections and correct condensing vent setup. DIY installation is not recommended for this high-BTU model.