180,000 BTU Condensing Tankless Water Heater

The RX180iN is Rinnai's condensing, natural-gas tankless water heater, built for homes with above-average hot-water demand that want continuous supply without a storage tank. It installs indoors or outdoors and mounts to the wall.

Rated at 180,000 BTU maximum input (15,000 BTU minimum) and 0.98 UEF energy factor, it holds a first-hour rating of 318 gallons. The unit runs on 120-volt power, draws 76 watts, and is rated to 10,200 feet of altitude and 150 PSI maximum water pressure between 98°F and 120°F. Digital controls and a digital temperature display are built in.

Installation is wall-mounted with a direct-vent connection, and Smart Circ intelligent recirculation is available with an accessory pump kit. Outdoor installation requires the separately sold Versa Vent cap (Rinnai #RXOVC). A qualified installer should confirm clearances, gas-line sizing, and local code before installation.

This listing is for the water heater itself. Gas piping, electrical connections, mounting hardware, and venting materials are not included unless stated.

Rinnai's limited warranty covers this natural-gas unit for 15 years (or 12,000 hours) on the heat exchanger, 5 years on parts, and 1 year on labor for residential use; commercial coverage is 8 years (or 12,000 hours), 5 years, and 1 year respectively.

Delivery and returns: this water heater ships free by ground delivery and arrives within the window shown above. If it is not the right fit, return it free within 30 days in its original packaging.

• Installation and Clearances

  This wall-mounted unit is listed for indoor or outdoor placement. Plan the installation location around the required clearances, access for service, gas and water connections, condensate routing, and local code. Have a qualified professional confirm the site before installation.

• Venting Requirements

  Outdoor placement requires the source-listed outdoor vent adapter and cap, sold separately. Confirm the approved vent materials, termination location, clearances, and any indoor venting requirements in the installation documentation before ordering accessories or scheduling the work.

• Natural Gas Supply

  This listing is the natural-gas configuration and ships as one fuel-specific variant. The 180,000 BTU maximum input makes gas-line sizing an installer decision. Verify natural-gas pressure, supply capacity, connections, and local code before installation.

• Flow and Temperature Rise

  The source lists a 0.13 gallons per minute minimum flow rate and a separate maximum flow value of 10 without a unit. Delivered hot-water flow depends on temperature rise, incoming water conditions, fixture demand, and installation.

• Controls and Recirculation

  Digital controls and a digital display support temperature adjustment at the unit. Bluetooth setup is source-listed, and recirculation is described as compatible with a pump or pump accessory kit. Confirm the required controls and pump configuration before planning the loop.

• Efficiency and Power

  Condensing technology and a source-listed 0.98 energy factor support efficient operation, with Energy Star 5.0 identified in the source features. The heater uses 120-volt power. Confirm electrical service and condensate handling with the installer.

• Flushing and Maintenance

  Plan routine service for the water conditions and usage at the installation. The source listing does not state a descaling schedule, so follow the installation and operation manual for flushing, descaling, cleaning, inspection, and maintenance records.

• Warranty Terms

  The source lists a limited warranty with 15 years or 12K hours on the residential heat exchanger, 5 years on parts, and 1 year on labor. Another source block shows different hour and labor terms, so verify the written warranty and registration requirements.

• What Ships

  The source lists one included piece and identifies the water heater, but it does not give a complete box-contents list. The outdoor vent cap is not included and is sold separately. Confirm included parts, venting, condensate materials, and pump-kit needs before installation.

Good to know

• Natural Gas configuration; verify gas-line sizing and pressure with a qualified installer.
• Wall mounted; confirm site, clearances, venting, and condensate needs before installation.
• Source details omit overall dimensions; use installation documentation for fit planning.
• Professional installation is required for wall mounting, gas, venting, electrical, and condensate connections.
• Water heater only. Installation materials and other items shown are not included unless stated.