Rheem RTEX-13 240V Residential Tankless Water Heater (Gray)

On‑Demand Hot Water, When You Need It

Meet the Rheem 240V Heating Chamber RTEX-13, a compact, gray tankless electric water heater designed for single point‑of‑use or multi‑application setups. It delivers hot water quickly and reliably, without the bulk of a traditional tank, making it a flexible choice for tight spaces and evolving layouts.

With an emphasis on precise control and efficient performance, this unit helps you tailor hot water to your daily routines—whether you’re running a kitchen faucet, a bathroom sink, or a small multi‑fixture setup. The goal is steady warmth on demand, not a bundle of variables you have to manage manually.

Smart, Precise Temperature Control

The external digital thermostat features an LED display that makes temperature adjustments clear and straightforward. You can set temperatures in small increments (1°) to fit sensitive tasks or comfort preferences, while the self‑modulating power control automatically scales energy use to match demand. The result is warmth when you want it, with efficiency built in.

Durable, Efficient Heat Source

Inside, copper immersion heating elements provide reliable heat transfer, and they’re field serviceable to support ongoing maintenance without a full replacement. The unit touts high energy efficiency (up to 99.8%), helping to minimize waste heat and support responsible energy use over time.

Easy Installation and Practical Features

Setup is straightforward thanks to practical design and included hardware. You’ll find 1/2 NPT adapters and side 1/2 inch compression water connections, with threading that supports straightforward replacement if needed. A digital temperature display helps confirm settings at a glance, so you’re never guessing.

Real‑World Use and Capacity

Ideal for under‑sink tasks, compact apartments, or small multi‑use areas where on‑demand hot water matters. The unit supports a flow rate up to 3.17 GPM under favorable conditions, with electrical requirements listed at 54 A and 13 kW for the model in question. Availability of hot water can depend on incoming water temperature and power supply.

Key Specifications at a Glance

• External digital thermostat with LED display for precise control
• Durable copper heating elements, field serviceable
• Simple hookup with included adapters and standard water connections
• Up to 99.8% energy efficiency; 1°F increments for temperature adjustments
• Water‑Saver Shower Head rated at 1.5 GPM to help reduce flow
• Compact, threaded design for easy replacement and maintenance

What This Could Mean for Your Home

Think of shorter wait times for hot water at a sink or shower, more predictable temperatures during busy mornings, and a streamlined setup in smaller spaces. While outcomes depend on your specific plumbing, power availability, and climate of incoming water, the RTEX‑13 offers a scalable option for on‑demand comfort without a storage tank.