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Rheem RTEX-13 Electric Water Heater Review

The Rheem RTEX 13 Review

Our Rating


The Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater is a great choice for everyone in need of an ideal residential water heater. Given that it is tankless, it is not only effective in its operations, but also its energy efficiency, which is something you will fall in love with.

It features a simple, yet compact design with great features, starting with the external adjustable digital thermostat control that comes with a LED display to give precise readings of the temperature of the water.

Its small and lightweight nature makes it suitable for use in smaller homes and apartments. Since it is so light, you don’t have to call a technician for installation because you can easily install it on your own.

The efficiency of the water heater and low consumption of energy has been necessitated by the inclusion of the two durable copper immersion heating elements that comes with self-modulating control. To enable you to control the temperature of the water you need, the unit has external controls that make it possible to adjust the temperature to your preferred range.

With the RTEX 13, you don’t have to worry about having the water being too hot or too cold because you can always know the current reading on the digital temperature display. At a retailing price of less than $300, this water heater is relatively affordable and makes it one of the best options for those in need of inexpensive ways to heat their water.

What Makes This Water Heater Stands Out?

  • Comes with great energy efficiency
  • Small, lightweight & easy to install
  • Adjustable digital thermostatic control
  • On-demand water heater
  • Reasonable pricing and excellent value


Dimensions: 4 x 9 x 13 inch

Weight: 4 pounds

Power Source: Corded Electric

Voltage: 24V

Wattage: 13 KW

Rheem Electric Water Heater Reviews:-Features of RTEX 13

1) Heater Performance

rheem electric water heater reviews

This an electric unit, which means it works through a system of internal heat exchangers and sensors, rather than firing up a live flame.

One downside to this is that you’ll need to install the unit directly above the sink where you want the hot water. However, if you’re living in a small apartment, this shouldn’t be a huge issue. 

2) Flow Rate

As other reviews were quick to highlight, in addition to its price, the most commendable feature of this model is the flow rate. It has a 4 Gallon per Minute rate, which allows you to run water on a low-graded tap and a shower simultaneously.

With such a flow rate, you’d think that this heater is larger than others in the same price range, however, that simply isn’t the case.

Even if you live in a smallish studio apartment, the RTEX 13 won’t occupy too much space. Another thing that makes it perfect for smaller homes is the source of its power supply. However, if you still are interested in the gas type tankless water heater, check out this article.

3) Heat Flow and Output

This unit can offer water as hot as 100 degrees Fahrenheit. So besides showering and dish-washing, you’ll be able to wash your clothes with this heater.

Although the GMP rate goes down with the temperature, flow delays are almost non-existent.

Simply put, this isn’t a unit that makes you wait a minute or two for the water to come flowing out of the shower or tap.

4) Temperature Control

With the RTEX 13, you’ll have complete control over your water temperature. The device allows you to fine-tune the temperature with augmentations of One Fahrenheit.

Moreover, the thermostat has an LED display, which allows users to set the temperature effortlessly.

What Makes The RTEX 13 Stands Out?

Energy Efficiency

Thanks to the modulating heat exchanger, the RTEX 13 is very energy-efficient. This part will ensure that there’s no heat loss, which allows the unit to conserve the electric energy.

As we mentioned before, since this is an electric unit, you don’t need a venting system to maintain it properly.

This also eliminates the emission of greenhouse gases. So if you want a strong but environmentally-friendly unit, this is the right heater for you.

Space Saving

The unit is so small, you can easily keep it under your sink if you want to save up space in your bathroom.

What’s more, you can actually keep it anywhere you want – even inside a small cabinet – since it takes up so little space.

This is what makes the RTEX 13 so ideal for small homes, studio apartment, and even professional offices and laboratories.

Ease of Use

The temperature control allows you to adjust the temperature without the need to open the unit.

Furthermore, the controls are so easy to use, even a young child would be able to grasp them. It has an LED indicator that shows when the heater is in standby mode and when it’s active.

While hiring a professional electrician to install the RTEX 13 is recommendable, you can actually do the job yourself in just a few hours. 

Heater Installation

If you want to install the unit on your own, you’ll need some special tools. Depending on the circuitry in your home and the tools you have on hand, you should acquire some of the following supplies:

  • Connectors
  • Conduits
  • Conductor wires
  • Junction Boxes

Despite the need for these supplies, the RTEX 13 is relatively easy to install so you don’t need to be a seasoned electrician to do the job.

A professional can install the unit in an hour or so and you can do it in about two hours.

We recommend you hire a professional for the job if you don’t want to void your warranty. Nonetheless, if you decide to do the work yourself, you probably won’t face too many difficulties.

You can check out this list of best electric tankless water heater if this model is too small for you.

Pros and Cons


  • It has a simple interface that’s simple to use for even the youngest household members.
  • The unit is pretty compact, so it won't take up too much space.
  • You can keep it in a closet, under a sink, or even little corner out of your way.
  • One of the inexpensive tankless water heater available on the market today.
  • Able to provide hot water to one low-rated tap and one shower in your home.
  • The perfect water heater if you live alone in a small studio apartment.


  • Not really great for households more than 4 members.

Final Verdict

Rheem RTEX 13 Electric Water Heater

Our Rating

Although the machine is relatively new, the RTEX 13 is already winning hearts of users across the world, with its reliable and user-friendly performance.

Don’t believe us? Just read one of the many Rheem RTEX 13 electric water heater reviews out there and you’ll see that most people share our opinion.

All in all, this is an easy-to-use, cost-effective water heater that will allow you to keep the water in your home hot at all times. We rate this heater 4.5 out of 5 stars.

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    Verner Ellen

    Hi, my name is Verner Ellen. I am a homebody whose interest is in getting the best home tools and equipments to help with the the everyday house chores. I also love fitness, cooking and grilling. Maintaining a clean and comfortable home is my lifelong passion.