Rheem RTEX-13 Review: The Best For Home Comfort?

Rheem RTEX-13

Last updated on May 5th, 2024 at 03:55 am

Tankless electric water heaters are an innovative solution for providing your home with hot water on demand without the bulk and energy inefficiency of traditional storage water heaters.

If you’re considering making the switch or upgrading your current system, you’ll want to know about options that combine efficiency with performance.

One such option is the Rheem RTEX-13, a compact unit from a trusted brand known for its quality products in the heating and cooling space.

With the Rheem manufacturing company model RTEX-13, Rheem aims to bring you continuous hot water that’s both quick and consistent for a variety of uses around the house.

Users appreciate the digital thermostatic control for its precision in temperature adjustments along with the external digital display.

The design also includes two robust copper immersion heating elements with brass known for their durability and serviceability. Simplicity is key with this model, offering easy installation and a user-friendly experience right from the start.

The energy efficiency is an added benefit, ensuring you’re being kind to the environment as well as your wallet.

Bottom Line

The Rheem RTEX-13 Tankless Water Heater stands out for its reliability and energy-saving features.

An ideal choice for hot water needs, this model is receiving nods for its user-friendly design and cost-saving operation.

Ready to make the switch? Click here to get your Rheem RTEX-13 and enjoy endless hot water.

Rheem 240V Heating Chamber RTEX-13 Overview

If you’re eyeing a tankless water heater for your home, the RTEX-13 might catch your interest with its sleek gray finish and compact dimensions, making it quite inconspicuous in any setting.

With just 8.25 inches in width and a height of 12.63 inches, it won’t demand significant space. The installation is straightforward, thanks to the 1/2 NPT adapters and side compression water connections provided. An electrician and plumber could ensure it’s set up correctly.

You’ll appreciate the external digital thermostat offering pinpoint dial control over your water temperature, adjustable by 1-degree increments. It boasts a self-modulating power control, which is pretty smart as it adjusts energy consumption based on water flow demand.

Despite concerns one might have about tankless heaters’ performance, the RTEX-13 has a decent flow rate of up to 3.17 GPM per minute single point of use, depending on your input water temperature.

Energy efficiency stands out as a notable feature at a remarkable 99.8%, meaning nearly all the energy consumed goes directly into heating your water.

On the downside, the use of plastic in the backplate has left some users feeling the build quality has diminished from older, more rugged designs. Yet, many users report the unit operating effectively even after a couple of years, suggesting reliability isn’t a major concern.

Remember, though, in colder climates, it may struggle to keep up if your household demands are high.

Why Choose Rheem RTEX-13: Key Benefits

Absolutely in the middle of finding that perfect blend of efficiency and convenience for your home water heating needs? The Rheem RTEX-13 might just be what you’re seeking. Offering a range of benefits, this tankless water heater blends technology with function to give you a seamless experience. Let’s dive into what makes it stand out.

Adjustable Digital Thermostatic Control

Imagine having precise digital temperature control over your water’s temperature with the press of a button. The RTEX-13 offers an external digital thermostatic control sporting an LED display for clear readability.

You have the power to adjust temperatures with incredible accuracy, ensuring you get the exact warmth you desire for your hot shower or bathroom sinks use—plus or minus one degree. Use a water-saver shower head with 1.5 gpm to enjoy greater savings on your water usage.

  • Precision: Adjust temperature in 1°F increments for exact heat levels.
  • Visibility: Clear LED display for easy monitoring of settings.
  • Control: Easily change settings externally without internal tinkering.

Energy Efficiency and Savings

One of the most compelling reasons to consider this model is its remarkable energy efficiency. With a 99.8% energy-efficient rating, almost every bit of power consumed goes directly into heating your water. This efficiency translates into savings on your utility bill, with less waste and more heat per dollar.

  • Energy Use: Self-modulating power control manages energy draw based on flow rate.
  • Money Saving: High efficiency means less energy waste and lower bills.
  • Eco-Friendly: A greener choice due to reduced power consumption.

Ease of Installation

You’ll be pleased to know that setting up the RTEX-13 doesn’t require a host of tools or professional expertise. Included are 1/2 NPT adapters, which make it compatible with existing water systems. This user-friendly design not only saves time but also allows for less complicated installation processes.

  • Simplicity: Straightforward installation with clear instructions and included adapters.
  • Convenience: No need for major plumbing modifications.
  • Support: Customer service and detailed manuals aid in a hassle-free setup.

Compact and Stylish Design

Your space is precious, and the RTEX-13 understands that. The unit sports a sleek, compact design that won’t take up unnecessary room. Grey in color and modern in aesthetics, it can complement a variety of interiors without being an eyesore.

  • Space Saving: Small footprint allows for installation in tight spaces.
  • Aesthetics: A modern look that can blend into home designs.
  • Build Quality: Copper immersion heating element increases durability and longevity of the heater.

In summary, the Rheem RTEX-13 brings together convenience and efficiency in a neat package, suitable for a range of households. Precision controls, top-tier energy savings, ease of installation, and a design that considers both space and visual appeal, create a compelling case for this water heater.

Whether you’re renovating or just looking to upgrade, it’s an option worth considering for continuous hot water on demand.

Rheem RTEX-13: Performance Features and Efficiency

If you’re on the lookout for a tankless water heater that balances performance with efficiency, the Professional Classic Series RTEX-13 might catch your attention. You’ll appreciate the LED display which simplifies adjusting the temperature for your comfort.

As for its heating capabilities, with a 13 kilowatt output and a maximum flow rate of 3.17 gallons per minute (GPM), this unit is designed for small to medium water usage demands.

Users have experienced a reliable supply of hot water for applications like kitchen sinks and dishwashers, even in wintry conditions where inlet water temperatures can be low.

However, if your climate is particularly cold, you may find it takes a little longer for the water to reach the desired heat. Additionally, for larger demands such as filling a bathtub, this model might not be quite up to the task in colder regions.

Installation feedback indicates some consumers found it straight-forward, while others preferred professional setup to ensure optimal performance and conformity to local electrical and plumbing codes.

Although compact and generally praised for its convenience and consistent hot water delivery, there’s also mention of a plastic backplate which could raise questions about long-term durability compared to previous metal models.

Overall, the Rheem RTEX-13 seems to offer a solid blend of efficiency and effective performance for its size, particularly in light of its favorable rating and user satisfaction over time.

Comparing the RTEX-13 With Other Brands

When you’re considering tankless water heaters, you’ll discover that the RTEX-13 stands out mainly for its energy efficiency and easy-to-use digital temperature display. It’s hard not to appreciate how it saves on energy with a staggering 99.8% efficiency rating. For homes with smaller space, its compact design can be a significant plus.

In contrast, you might come across models from brands like Ecosmart or Stiebel Eltron, which also boast energy efficiency and performance, but might differ in the specifics of installation or flow rate capacities. For instance, Ecosmart units often require more extensive installation and might offer a higher flow rate which is ideal for larger homes.

Choosing the Rheem model could be the better fit for your smaller applications or specific point-of-use needs, thanks to its simple installation and adjustable control. This means getting hot water where and when you need it, without paying for a larger unit’s extra capacity that might go unused.

However, if you’re in a colder climate and require a high flow for simultaneous applications, you may be inclined to look at alternatives that handle higher demands better. The balance between efficiency, size, installation ease, and precise temperature control makes the RTEX-13 a contender worth considering in its category.

Cost and Value Analysis

When considering the Rheem RTEX-13, its upfront cost is a key factor to weigh against the benefits you’ll receive. With its energy efficiency at 99.8% and features like an adjustable digital thermostat, you’re looking at savings on your energy bill every month.

]Although the initial investment might seem considerable, especially if you need to upgrade your electrical installation to accommodate the 240V requirement, the RTEX-13 is designed to be a durable solution for your hot water needs.

The self-modulating power control is a standout feature that helps to optimize electricity use. This means the heater only consumes energy when you’re using hot water, potentially leading to significant energy savings over time.

Additionally, the simplicity of installation can also translate into lower setup costs, as the provided adapters and detailed digital temperature display assist in a straightforward setup process.

Overall, the quality of construction and smart features suggest a long lifespan, offering value well beyond its price point. However, keep in mind that higher flow rates in cooler climates might challenge this tankless heater’s performance.

It’s about balancing your needs with the capability of the RTEX-13, ensuring you get the most bang for your buck in the long run.

Pros and Cons

When considering the RTEX-13, it’s all about balancing efficiency with installation and build quality. Let’s break down the benefits and drawbacks.


  • Energy Efficiency: With a 99.8% energy efficiency rating, you’ll be hard-pressed to find a tankless water heater that runs leaner.
  • Temperature Control: You get precision control over water temperature, thanks to the external digital thermostat and LED display – adjust in 1-degree increments for your perfect heat.
  • Flow Rate: 13kW model flow rate of up to 3.17 gallons per minute (GPM), it should meet the needs for smaller households seamlessly.
  • Compact Design: Its size makes it a non-obtrusive addition to your home, providing hot water without taking up much space.
  • Installation: Comes with 1/2 NPT adapters, geared towards simpler setup. Plus, for those moderately handy, installation is straightforward.


  • Installation Cost: While installation is simpler, you may still need a professional for the electrical and plumbing work, which could add to the overall cost.
  • Build Quality Concerns: Some users have mentioned the plastic backplate feels less durable compared to older models with metal enclosures.
  • Climate Limitations: If you’re in a colder region, the heater may struggle to keep up with the demand for high flow taps, such as tubs.
  • Accessories Not Included: There have been notes on the lack of detailed information about necessary wiring and plumbing parts that aren’t included but are required for installation.
  • Initial Wait Time: It’s been flagged that hot water may take 30 seconds to a minute to reach the tap, especially in colder climates or with longer plumbing runs.

Customer Reviews

Many users have found the RTEX-13 to be a reliable and effective solution for their hot water needs. It’s been noted for its ease of installation and capability to deliver hot water consistently. Some customers have shared that they needed to adjust the temperature down due to its efficiency in heating water.

After a couple of years, customers report that the unit continues to operate without issues, indicating good durability. There’s satisfaction expressed about the unit’s compact size, which makes it an ideal choice for those with limited space.

Although an electrician and plumber may be needed for installation, the consensus is that the product works well with typical home electrical services.

However, some customers have mentioned that the quality of the materials, specifically the use of a plastic backplate, could be improved.

Concern has been raised over the adequacy of the flow rate in very cold climates or for high-demand applications like filling a bathtub. Additionally, certain customers felt the documentation could be clearer regarding wiring and plumbing requirements.

Remember, the effectiveness of the RTEX-13 can vary based on individual household needs and climates. A few customers suggested reading through the specifications carefully to ensure compatibility with your intended use.

Overall, this tankless water heater from Rheem seems to be a good fit for many, especially for those prioritizing continuous hot water and space-saving design.


When considering the purchase of a tankless water heater, the RTEX-13 stands out for its ability to deliver hot water on demand effectively. Your concerns for durable construction might be raised due to some feedback about a switch from metal to plastic components.

Yet, you’ll find reassurance in the multitude of users who praise its consistent performance over time. The installation process could require professional help, and the impact on your energy system is minimal, especially if efficiency is a priority in your household.

If your home is in a cooler climate or if you’re considering it for high flow applications, the RTEX-13 might not meet your expectations of temperature rise. However, for average use, like washing dishes or a kitchen sink setup, it seems reliable. While not every accessory is included, it’s a detail that can be managed with a little extra preparation.

In essence, the RTEX-13 by Rheem appears to be a worthy investment if your hot water needs align with its capacity and features. Its user-friendly temperature control and compact size have resonated well with plenty of customers, making it a considerable option for those looking to dip their toes into the world of tankless water heating.

Recommended Products (if Rheem RTEX-13 is not suitable)

For those who find that this professional classic tankless electric heater isn’t quite the right fit, there are other great options on the market to consider. For example, the Ecosmart ECO 11 might be better if you’re looking for something more energy-efficient in smaller homes, offering a self-modulating power technology and a compact size that saves on storage.

Another excellent choice could be the Stiebel Eltron Tempra 24 Plus. It’s known for its advanced flow control that automatically maintains water temperature for consistent comfort. It’s ideal if your household has a higher demand for hot water or if you prefer a more silent operation.

If you’re on a budget, yet in need of a reliable unit, the Bosch Electric Mini-Tank Water Heater Tronic 3000 T can be a convenient under-sink solution. This mini-tank heater is easy to install, providing hot water right where it’s needed without the wait.

Remember to evaluate your specific needs regarding flow rates, energy savings, space, and usage to find the best tankless water heater that matches your requirements.


  • Edmund Yeo

    🌱 I'm passionate about sustainable living and renewable energy, and I'm thrilled to share my journey towards a greener, brighter future with you. Join me as I explore the latest innovations, eco-friendly lifestyle tips, and inspiring stories from the forefront of the green energy revolution. Note: This website uses affiliate links which may earn a commission for purchases made at no additional cost to you.

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