Rheem RTG-64XLN Natural Gas, Outdoor Whole House Tankless Water Heater, 6.4 GPM

Item #: BCI1330866

Offer Ends

Originally $852.55, You Save 4%
Shipping: Free Shipping! See Details
Ships In:
Leaves the Warehouse in 1 to 3 weeks
Made To Order


Please finish configuring product before adding to cart

Get it installed by a Home Advisor Pro

Technical Specs

Specification Sheet
Depth 9.875
Direct Vent No
Energy Star Yes
Fuel Type Natural Gas
Gas Connection 3/4"
Hardwired Yes
Height 25.625
Ignition Type Electronic
Indoor Installation No
Low Lead Compliant Yes
Manifolding Yes
Maximum Flow Rate 6.4
Maximum Gas Input 150000
Maximum Temperature 140
Minimum Flow Rate .26
Minimum Gas Input 11000
Outdoor Installation Yes
Plug In Yes
Water Connection 3/4"
Width 13.875

Natural Gas, Outdoor Whole House Tankless Water Heater, 6.4 GPM


ALL THE HOT WATER YOU'LL EVER NEED… when you need it. It's that simple. The popularity of oversize tubs is growing, and so is the demand for large volumes of low-cost hot water. The Rheem Tankless provides a compact solution for a continuous supply of energy-efficient hot water that won’t run out.

ENERGY-EFFICIENT DESIGN… low-cost operation. Why keep 40-50 gallons of water hot when you don’t need it? It’s expensive to continue to heat and re-heat water when you’re not home or not using it. Rheem’s tankless design offers convenience without the high cost of keeping water hot.

COMPACT SIZE… good things do come in small packages. Rheem Tankless is about one third the size of a conventional water heater. Sophisticated technology has reduced the size and increased the features and benefits. A digital display makes setting a precise water temperature, or monitoring the unit’s status, a snap! Its compact size will leave room for a water softener or extra storage.


Product Features:

  • Includes UMC-117 Remote Control: Designed to be installed in the kitchen, the UMC-117 gives users complete control of their tankless unit by putting temperature controls at you finger tips.
  • .40 GPM Minimum Activation Flow Rate: Best in the industry, Rheem's units work very well with low-flow faucets, WaterSense faucets, and other applications which don't draw much water.
  • .26 GPM Minimum Flow Rate: Also a best in the industry, Once activated, water pressure can be reduced down to a trickle without de-activating the unit.  This feature is especially useful in the kitchen, and yet surprisingly overlooked by other tankless manufacturers.
  • Self Diagnostic: Should maintenance be required, the unit’s self-diagnostic system will display a maintenance code on the remote control, taking the guess-work out of trouble shooting.
  • Energy Star Compliant: All tankless units require electricity to operate the internal fan and motherboard.  Rheem has designed their units to draw only what is operationally required, eliminating stand-by losses and earning Energy Star certification.  Units are shipped with a standard 120V power cord.
  • Guardian OFW™ Overheat Film Wrap:  This monitors the temperature of the heat exchanger and will shut the unit down if it exceeds a safe temperature. This is an exclusive feature of the Rheem tankless water heaters.
  • Electronic Ignition:  Spark ignited when flow is detected, Rheem units eliminate dangerous and wasteful pilot lights altogether.
  • Environmentally Friendly Low NOx Burner: meets SCAQMD rule 1146 requirements for emissions standards.
  • Freeze Protection: to -30° F
  • Manifolding-Ready: When one tankless unit just isn't going to be enough, manifolding two units together is not only possible, but relatively easy.  Through the use of an EZ-Link Cable (RTG20040), units can communicate with each other, dividing the work load.
  • Warranty:  Heat Exchanger Warranty: 12 Years; Parts Warranty: 5 Years; Labor Warranty: 1 Year


Performance Data:

The figures below represent performance estimates and are for sizing purposes only.  The RTG-64X was designed for use in a single bathroom home.  For larger applications, consider using the RTG-84X, RTG-95X or manifolding two RTG-64X's together.  Please keep in mind that ground-water temperatures vary by region and season. 

  • 6.4 GPM @ 35° Temp. rise
  • 5.6 GPM @ 45° Temp. rise
  • 5.1 GPM @ 50° Temp. rise
  • 4.2 GPM @ 60° Temp. rise
  • 3.6 GPM @ 70° Temp. rise
  • 3.3 GPM @ 77° Temp. rise


Venting Requirements:

Because this is an outdoor unit, no venting is required. 

Popular Accessories:

  • EZ-Link Cable (RTG20040): For manifolding more than one unit together, this cable provides a communication channel between two units allowing for even distribution of work load.
  • Flush Kit (RTG20124): Periodically, any tankless unit needs to be flushed to remove naturally occurring mineral deposits.  This kit provides the necessary components to complete this service.
  • Pipe Cover (RTG20169DVG): A purely cosmetic accessory, this piece covers the piping that is otherwise visible at the bottom side of the unit. 

Additional Rheem Links


This product is listed under the following manufacturer number(s):

  • N/A

*Denotes a finish or option that has been discontinued

0 Question from the Community


Doesn't Ship Direct!

Warranty Info

Rheem Warranty Info

NOTICE FOR CANADA: All Canadian customers please contact Rheem Canada Warranty at 1 800 263 8342 (hours of operation: 8:30 am - 4:30 pm EST Monday-Friday) to verify the warranty of your water heater. Web warranty verification is for US customers only.

Registration of your unit must be done at www.Rheem.com for the warranty to be valid

Please visit www.Rheem.com for specific information regarding your unit

Recently Viewed Items