A.O. Smith Tankless Water Heater – 10.5 GPM – Model ATHR-199X3

This A.O. Smith tankless water heater, model ATHR-199X3, has a heating capacity of 199,000 BTU with a maximum flow rate of 10.5 Gallons Per Minute (GPM). It is designed to provide reliable hot water for a home with 4–6 occupants in regular conditions. This tankless water heater uses natural gas as its fuel source and features a direct vent exhaust system. This type of venting allows combustion gases to be expelled directly outside, improving safety and maximizing overall efficiency. Thanks to its tankless design, it saves valuable space and can be easily mounted on the wall.

A.O. Smith is one of the most trusted brands in the water heater industry, manufacturing a wide range of residential and commercial models. In terms of price, the ATHR-199X3 falls within the high-range category and is an excellent choice for customers who prioritize premium performance, superior comfort, and long-term value.

The average lifespan of a tankless water heater typically ranges from 15 to 20 years. Installation quality, maintenance frequency, and local water conditions can all impact longevity. Regular maintenance—such as flushing the system and descaling the heat exchanger—helps prevent mineral buildup and ensures consistent performance. This unit has a Uniform Energy Factor (UEF) of 0.95, placing it in the Super High-Efficiency class. It is Energy Star certified, meeting strict energy-saving standards that help reduce utility bills and support a lower environmental footprint.

This model includes a 15-year warranty on the heat exchanger and a 5-year warranty on parts. When you purchase this product from HVAC Near Me, you can take advantage of long-term financing options ranging from 1 to 20 years. You will also receive a free 1-year labor warranty, with the option to extend coverage to 5 or 10 years for added protection and peace of mind.

Documents

• AO-Smith ATHR-199X3 Spec
• ATHR-199X3 Manual