Warranties 
Rebates 
Tax Credits 
Sustainability 
Careers 
Help 
Professional Classic Series Tankless Electric RTEX-18 kW
MODEL RTEX-18 (208V PERFORMANCE)
Heating Chamber - 5 Years
Parts - 1 Year
- UEF up to .94
- Flow rate up to 4.4 GPM
- Durable powder-coated shell with a galvanized steel backplate.
- Digital thermostatic temperature controls in 1-degree increments ranging from 80°F - 140°F (26°C - 60°C)
Select GPM
7
GPM
SKU RTEX-18 (208V PERFORMANCE)
Warranty Years 5
Model Professional Classic Tankless Electric RTEX-18
GPM 7
Depth 3.5"
Height 18.25"
Width 14.5"
Single Shower Minutes 9999
Number Back To Back Showers 9999
Install Location Indoor
High Efficiency Yes
Kilowatts 13
Amps 75
Recommended Breaker Size 2x40
Voltage 208
RecommendedWireSize 8
Maximum Flow GPM 7
Adjustable Thermostat False
Professional Classic® tankless electric water heaters offer continuous hot water quick and on demand for single point-of-use or multiple applications
Performance Features
- Saves Space – up to 93% smaller than a standard electric water heater
- Saves Energy – zero standby heat loss when installed near the point-of-use
- More Hot Water – up to 4 times the hot water delivery of a standard electric tank (per hour)
- consumes the power needed to satisfy hot water demand
- Copper immersion heating elements fit into a multi-chamber design to improve the thermal performance providing better temperature control and faster recovery of hot water
- Designed to be mounted in an upright position with the inlet and outlet water connections at the bottom of the unit for ease of installation
- Venting is not required to operate, simplifying the installation process compared to a gas tankless water heater
- Warranty 5 Years - Leaks, 1 Year – Parts
Applications
- Standard Hand Sink – 0.5 GPM
- Washing Machine – 1 to 1.5 GPM
- Kitchen Sink – 1 to 2 GPM
- Dishwasher – 1 to 2 GPM
- Water-Saver Shower Head – 1.5 GPM
- Standard Shower Head – 2.0 GPM
- Bath Tub – = 4 GPM
Average Gallons Per Minute (GPM) based on 2010 Plumbing Standards
| MODEL NUMBER | MAX FLOW (GPM) |
| RTEX-18 | 4.4 |
Heating Chamber - 5 Years
Parts - 1 Year
More Residential Rheem Products
Find additional documentation by viewing these related products.
Professional Classic Series Tankless Electric RTEX-3.5, RTEX-06 kW
- UEF up to 0.95
- Flow Rate up to 1.6 GPM (See specification sheet for the GPM on each model)
- Digital temperature control in 1-degree increments ranging from 80°F - 140°F (26°C - 60°C)
- Two 0.35 GPM aerators are included for optimal temperature output and performance
Professional Classic Series: RTEX-04T, RTEX-06T
- Efficient Design – UEF up to .95 and advanced self-modulating technology only consumes the power needed to satisfy hot water demand
- Flow Rate up to 0.25 GPM
- Digital thermostatic temperature controls in 1-degree increments ranging from 80°F - 140°F (26°C - 60°C)
- Includes two optional 0.35 GPM aerators (flow restrictors) for optimal temperature output and performance
- Stainless steel heat exchanger reduces corrosion for long life.
- Brass 1/2" NPT fittings located on the bottom for the inlet and outlet water connections.
Professional Classic Series: RTEX-04T, RTEX-06T
- Efficient Design – UEF up to .95 and advanced self-modulating technology only consumes the power needed to satisfy hot water demand
- Flow Rate up to 0.25 GPM
- Digital thermostatic temperature controls in 1-degree increments ranging from 80°F - 140°F (26°C - 60°C)
- Includes two optional 0.35 GPM aerators (flow restrictors) for optimal temperature output and performance
- Stainless steel heat exchanger reduces corrosion for long life.
- Brass 1/2" NPT fittings located on the bottom for the inlet and outlet water connections.
Professional Classic Series Tankless Electric RTEX-04T kW, RTEX-06T kW
- Efficient Design – UEF up to .95 and advanced self-modulating technology only consumes the power needed to satisfy hot water demand
- Flow Rate up to 0.25 GPM
- Digital thermostatic temperature controls in 1-degree increments ranging from80°F - 140°F (26°C - 60°C)
- Includes two optional 0.35 GPM aerators (flow restrictors) for optimal temperature output and performance
- Stainless steel heat exchanger reduces corrosion for long life
- Brass 1/2" NPT fittings located on the bottom for the inlet and outlet water connections
