A. O. Smith’s ADAPT™+ Premium condensing gas tankless water heaters available in 180k, and 199k BTU/Hr, deliver robust, on-demand performance and the flexibility to install in practically any residential setting. There are two design options available including models with integrated X3® Scale Prevention Technology, and Bypass (M) models. Easily add scale prevention protection to any M model by replacing the bypass cartridge with an optional X3 cartridge sold separately. X3 Scale Prevention Technology helps protect the heat exchanger resulting in up to three times longer life than a standard tankless water heater while maintaining like-new performance.

The ADAPT™+ Premium line with integrated recirculation pump features a built-in control display for setting and reviewing up to two recirculating schedules, as well as checking heater status and error codes. Manage temperature settings and activate the heater and recirculation remotely with optional kits (sold separately). All models are ENERGY STAR® certified and extremely efficient with a Uniform Energy Factor of 0.95, and also comply with Ultra-Low NOx regulations.



All ADAPT™+ Premium models are field convertible from Natural Gas to Liquid Propane, kit included, and can be installed indoors or outdoors (with an Outdoor Vent Cap Kit sold separately). Cascade up to 12 like heaters together for larger applications requiring multiple water heaters to work in conjunction, cable included.

When you open a hot water tap, cold water flows into the tankless unit and through A. O. Smith’s X3® Scale Prevention cartridge, which stops minerals from bonding and forming scale. This innovative design allows particles to pass harmlessly through the system, eliminating the need for regular descaling and helping your water heater last up to 3x longer than conventional tankless models.

Once treated, the water moves through a primary heat exchanger, where it is rapidly heated. A. O. Smith condensing tankless units deliver endless hot water on demand, save space, and operate only when needed, reducing standby energy use. Paired with a 15-year limited warranty, these water heaters are built for long-lasting performance, lower maintenance costs, and consistent comfort. There are no hard water warranty exclusions with X3-equipped models.