Finding the right water heater can feel overwhelming. With countless options available, many homeowners grapple with the choice between traditional tank systems and modern tankless models. Tankless water heaters promise continuous hot water, energy savings, and a compact design, making them an attractive option. However, the effectiveness of these systems can vary significantly between brands and models.
A great tankless water heater should deliver a reliable flow of hot water while maintaining energy efficiency and ease of installation. Rheem has built a strong reputation in the industry, known for its innovative technology and commitment to quality. In this review, we’ll explore the features, performance, and user feedback on the Rheem 240V Heating Chamber RTEX-13, a popular electric tankless water heater.
We’ll take a closer look at what makes the Rheem RTEX-13 stand out, its strengths and weaknesses, and how it compares to other options in the market. This thorough review aims to provide you with the insights needed to make an informed decision.
Here’s a quick comparison of the key specifications:
| Features | Rheem RTEX-13 |
|---|---|
| Power Source | Electric |
| Flow Rate | Up to 3.17 GPM |
| Energy Efficiency | 99.8% |
| Heating Elements | Two Copper Elements |
| Temperature Control | Digital, +/- 1°F |

Rheem 240V Heating Chamber
Rheem
Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater, GRAY
- External adjustable digital thermostatic control with LED display (+/1 degree accuracy
- Durable Copper immersion two heating elements, field Serviceable.Self-modulating power control
- Simple installation – 1/2 NPT adapters included; side 1/2 inch Compression water connections
The Rheem 240V Heating Chamber RTEX-13 is designed for residential use, making it ideal for smaller homes or apartments. Its compact design allows for flexible installation options, which is a significant advantage when space is limited. This model is best suited for households with moderate hot water needs, such as those with one or two bathrooms.
What sets the Rheem RTEX-13 apart from competitors is its high energy efficiency rating of 99.8%. This means it uses less power than traditional water heaters while providing an endless supply of hot water. The external digital thermostatic control with an LED display allows users to set the desired water temperature in precise 1°F increments. This feature not only enhances user experience but also contributes to energy savings.
However, it’s essential to note that while the RTEX-13 is efficient, it may struggle to meet the hot water demands of larger households. If your home has multiple bathrooms or simultaneous hot water needs, you might need to consider a higher flow rate model. Additionally, installation can be straightforward, but some users may require professional assistance to ensure proper setup.
- Power Source: Electric
- Flow Rate: Up to 3.17 GPM
- Energy Efficiency: 99.8%
- Heating Elements: Two Copper Elements
- Temperature Control: Digital, +/- 1°F
Best for: Ideal for small to medium households with moderate hot water needs.
How We Chose These Products
Our evaluation process involved careful research into various tankless water heaters, focusing on performance, energy efficiency, user feedback, and installation requirements. We compared Rheem’s offerings against other leading brands to understand their strengths and weaknesses. Customer reviews and expert opinions played a critical role in assessing real-world performance and reliability.
We also considered the long-term value of each product, including energy savings and maintenance requirements. Understanding how each model holds up over time helps guide buyers in making informed decisions, ensuring they invest in a product that will serve them well for years to come.
Buying Guide: What Really Matters
When selecting a tankless water heater like the Rheem RTEX-13, several factors should guide your choice. First, consider the flow rate, which indicates how much hot water the unit can deliver at once. For larger families or homes with multiple bathrooms, a higher flow rate is essential. Conversely, smaller households may find a lower flow rate adequate.
Energy efficiency is another critical consideration. Higher efficiency ratings mean lower energy bills, which can lead to significant savings over time. Look for models with at least a 90% efficiency rating to ensure cost-effectiveness. Finally, consider the installation requirements. While some models can be installed DIY, others may need professional assistance, which can add to the overall cost.
Our Top Recommendation
The Rheem 240V Heating Chamber RTEX-13 stands out as an excellent choice for small to medium households. Its high energy efficiency, compact design, and precise temperature control make it a reliable option for anyone looking to upgrade their hot water system. For those with larger families or higher hot water demands, consider exploring Rheem’s higher flow rate models or other brands that offer more robust solutions.
Frequently Asked Questions
1. How long does a Rheem tankless water heater last?
The average lifespan of a Rheem tankless water heater is around 20 years, provided it is well-maintained.
2. Can I install the Rheem RTEX-13 myself?
While some users may manage a DIY installation, professional installation is recommended to ensure safety and efficiency.
3. What maintenance does the Rheem RTEX-13 require?
Regular descaling and flushing are recommended to maintain performance and extend the unit’s lifespan.
4. How does the Rheem RTEX-13 compare to gas models?
Electric models like the RTEX-13 are typically easier to install and maintain than gas models, but gas units may offer higher flow rates.

