The A.O. Smith ATHR-199X3 Tankless Water Heater is a high-performance, condensing tankless system designed to deliver powerful and consistent hot water for modern residential applications. With a maximum heating capacity of 199,000 BTU and a flow rate of up to 10.5 GPM, this unit is well-suited for homes with approximately 4–6 occupants, ensuring stable hot water delivery even during simultaneous usage.
Powered by natural gas, the ATHR-199X3 features a direct vent system that safely expels combustion gases outside the home, improving indoor air safety while maximizing energy efficiency. Its compact, wall-mounted tankless design helps save valuable floor space, making it an ideal solution for mechanical rooms, utility closets, and modern home layouts where space optimization is important.
High-Efficiency Condensing Performance
The A. O. Smith ATHR-199X3 is a high-efficiency condensing tankless water heater designed to deliver reliable on-demand hot water while minimizing energy consumption. With a strong efficiency rating of 0.95 Energy Factor, it helps reduce utility costs while maintaining consistent performance.
Powerful 199,000 BTU Heating Capacity
Built for demanding residential applications, this unit offers up to 199,000 BTU heating capacity, ensuring stable hot water delivery even in homes with multiple bathrooms and simultaneous water usage.
10.5 GPM High Flow Performance
With a maximum flow rate of 10.5 gallons per minute (GPM), the ATHR-199X3 is capable of supporting multiple fixtures at the same time, making it ideal for larger households.
Built-in Recirculation System
The integrated built-in recirculation system improves hot water delivery speed by reducing wait times at faucets and showers, enhancing overall comfort and water efficiency.
Direct Vent System for Safe Operation
The unit features a direct vent configuration, which safely expels combustion gases outdoors while improving overall system efficiency and installation flexibility.
ENERGY STAR® Certified Efficiency
This model is ENERGY STAR® certified, meaning it meets strict energy efficiency standards designed to reduce environmental impact and long-term operating costs.
Compact Wall-Mounted Design
The tankless design allows for space-saving wall-mounted installation, freeing up valuable floor space compared to traditional tank water heaters.
Reliable Long-Term Warranty Coverage
The ATHR-199X3 is backed by strong manufacturer protection, including:
| Brand | A.O. Smith |
|---|---|
| Family | ATHR |
| Series | ProLine XE Condensing Tankless |
| Nominal GPM | 10.5 GPM |
| Heating Capacity | 199,000 BTU |
| Built-in Recirculation System | Yes |
| Venting Type | Direct Vent |
| Energy Factor | 0.95 |
| WiFi Capable | No Wi-Fi |
| Weight | 73 lbs |
| Product Depth | 23.8" |
| Energy Star | Yes |
| Warranty on Heat Exchanger | 15-Year |
| Warranty on Parts | 5-Year |
| Warranty on Labour | 1-Year |
The ATHR-199X3 is engineered for high energy efficiency, featuring a Uniform Energy Factor (UEF) of 0.95, placing it in the super high-efficiency class of tankless water heaters. It is also ENERGY STAR® certified, meeting strict energy performance standards that help reduce utility consumption and environmental impact.
Under normal operating conditions, tankless water heaters typically last 15 to 20 years, and the ATHR-199X3 is built to perform reliably throughout its lifespan. Proper installation and regular maintenance—such as system flushing and heat exchanger care—play a critical role in maintaining peak efficiency and preventing scale buildup, especially in areas with hard water.
The ATHR-199X3 is an ideal solution for homeowners seeking a powerful, space-saving, and energy-efficient tankless water heater. Its combination of high BTU output, stable flow performance, and advanced efficiency technology makes it suitable for demanding residential environments.
With its compact wall-mounted design, reliable direct venting system, and premium construction, this model delivers consistent hot water comfort while helping reduce long-term operating costs and maintenance requirements.
Pacific Blue Mechanical provides professional supply, installation, repair, maintenance, and replacement services for the A. O. Smith ATHR-199X3 ProLine XE Condensing Tankless Water Heater throughout Metro Vancouver and surrounding areas.
If requested, we can source and supply this high-efficiency A. O. Smith ATHR-199X3 tankless water heater directly and complete a full professional installation process, including natural gas line connection, cold and hot water piping integration, direct vent system installation, condensate drainage setup, wall mounting, built-in recirculation configuration, system startup, and full commissioning to ensure safe, efficient, and reliable operation.
Our licensed technicians also provide ongoing tankless water heater maintenance and repair services, including heat exchanger inspections, built-in recirculation system diagnostics, flow sensor testing, ignition troubleshooting, gas pressure balancing, error code diagnosis, venting performance checks, and complete system flushing and descaling when required to maintain peak efficiency.
If your current tankless water heater is experiencing inconsistent hot water, reduced efficiency, circulation issues, ignition problems, or is nearing the end of its service life, our team can evaluate your system and recommend the most cost-effective repair or full replacement solution tailored to your home’s hot water needs.
The ATHR-199X3 has a powerful 199,000 BTU heating capacity, making it suitable for larger homes with higher hot water demand.
This model provides a maximum flow rate of 10.5 gallons per minute (GPM), allowing multiple fixtures to run at the same time.
Yes, the unit includes a built-in recirculation system, helping reduce wait times for hot water and improving overall comfort and efficiency.
Yes, it has a 0.95 Energy Factor (UEF equivalent) and is ENERGY STAR® certified, ensuring high efficiency and lower energy consumption.
The ATHR-199X3 comes with a 15-year warranty on the heat exchanger, 5-year warranty on parts, and a 1-year labour warranty.
