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  • A. O. Smith ProLine XE X3 Tankless gas water heaters

    A. O. Smith Gas Tankless Water Heaters

    The A. O. Smith full line of natural gas and propane tankless water heaters continue to be an innovative part of the full A. O. Smith product family. The new X3 technology prevents scale buildup and extends the lives of units by up to three times.

    Learn More About Gas Tankless Water Heaters >

    Learn More About X3 Technology >


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    Gas Tankless Water Heaters

    Sort: Showing 1-15 of 36 Show   per page
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    Flow Rate
    BTU Input
    Limited Warranty - Heat Exchanger
    Features
    Technology
    Emissions
    Fuel Type
    Location
    UEF
    Weight
    ENERGY STAR

    Tankless Water Heater Condensing X3 199,000 BTU AT-199X3P Natural Gas/Propane

    AT-199X3P
    • 15 Year Limited Warranty
    • 199,000 BTU
      •
    ENERGY STAR

    Tankless Water Heater Condensing X3 180,000 BTU AT-180X3P Natural Gas/Propane

    AT-180X3P
    • 15 Year Limited Warranty
    • 180,000 BTU
      •
    ENERGY STAR

    Tankless Water Heater Condensing X3 160,000 BTU AT-160X3P Natural Gas/Propane

    AT-160X3P
    • 15 Year Limited Warranty
    • 160,000 BTU
      •

    Tankless Water Heater Non-Condensing Concentric Vent Indoor 199,000 BTU Natural Gas/Propane

    ATI-510C-N
    • 15 Year Limited Warranty
    • 199,000 BTU
      •

    Tankless Water Heater Non-Condensing Concentric Vent Indoor 190,000 BTU Natural Gas/Propane

    ATI-310C-N
    • 15 Year Limited Warranty
    • 190,000 BTU
      •

    Tankless Water Heater Non-Condensing Concentric Vent Indoor 140,000 BTU Natural Gas/Propane

    ATI-110C-N
    • 15 Year Limited Warranty
    • 140,000 BTU
      •

    Find a Professional

    A. O. Smith water heaters are available through your local plumbing professional. Find one near you.
    ENERGY STAR

    Tankless Water Heater Condensing Ultra-Low NOx Indoor 199,000 BTU Natural Gas

    ATI-540H-N
    • 15 Year Limited Warranty
    • 199,000 BTU
      •
    ENERGY STAR

    Tankless Water Heater Condensing Ultra-Low NOx Indoor 199,000 BTU Natural Gas

    ATI-540P-N
    • 15 Year Limited Warranty
    • 199,000 BTU
      •

    Tankless Water Heater Non-Condensing Ultra-Low NOx Indoor 199,000 BTU Natural Gas

    ATI-510U
    • 15 Year Limited Warranty
    • 199,000 BTU
      •
    ENERGY STAR

    Tankless Water Heater Condensing Ultra-Low NOx Indoor 180,000 BTU Natural Gas

    ATI-340H-N
    • 15 Year Limited Warranty
    • 180,000 BTU
      •

    Tankless Water Heater Non-Condensing Ultra-Low NOx Indoor 190,000 BTU Natural Gas

    ATI-310U
    • 15 Year Limited Warranty
    • 190,000 BTU
      •
    ENERGY STAR

    Tankless Water Heater Condensing Ultra-Low NOx Indoor 160,000 BTU Natural Gas

    ATI-240H-N
    • 15 Year Limited Warranty
    • 160,000 BTU
      •

    Find a Professional

    A. O. Smith water heaters are available through your local plumbing professional. Find one near you.

    Tankless Water Heater Non-Condensing Ultra-Low NOx Indoor 140,000 BTU Natural Gas

    ATI-110U
    • 15 Year Limited Warranty
    • 140,000 BTU
      •
    ENERGY STAR

    Tankless Water Heater Condensing Ultra-Low NOx Outdoor 199,000 BTU Natural Gas

    ATO-540H-N
    • 15 Year Limited Warranty
    • 199,000 BTU
      •
    ENERGY STAR

    Tankless Water Heater Condensing Ultra-Low NOx Outdoor 199,000 BTU Natural Gas

    ATO-540P-N
    • 15 Year Limited Warranty
    • 199,000 BTU
      •
    Sort: Showing 1-15 of 36 Show   per page
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AO Smith

©2018, A. O. Smith. All Rights Reserved. 1-877-552-0010
A. O. Smith reserves the right to make product changes or improvements at any time without notice.

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