Rheem RTE 13 Review: Should You Go For It?

Rheem RTE 13 tankless water heater Review

In the field of tankless water heaters, Rheem is a very popular brand. One popular unit from the brand that has managed to gain some attention on the market is the Rheem RTE 13 electric tankless water heater 4 GPM.

Rheem water has a long history of providing innovative water heating solution including a large variety of types and models that are suitable for different home sizes, applications and more. The brand’s most popular offering is tank-type water heaters. Rheem has a selection of electric, gas, and even solar powered models, in tank capacities of 20 to 80 gallons with energy efficient technology and advanced features.

The Rheem RTE 13 Tankless Water Heater makes use of an on-unit temperature control system. The system makes it possible to have a continuous hot water supply on demand and it’s also great for the point of use applications. The unit also has LEDs that usually indicate its standby mode and active elements. It also uses a standard a half-inch water connection. The unit uses a rugged copper and brass heat exchanger. It also features a compact design that makes sure that you can fit it anywhere.

Rheem RTE 13 Tankless Water Heater Review

The Rheem RTE 13 Tankless Water Heater is an ideal choice for single showers as it gives you the hot water that you require on-demand. At its 4 GPM maximum flow rate, you will enjoy that fresh burst of hot water right whenever you need it.

Features of Rheem RTE 13

Rheem RTE-13 Review1 Flow Rate: Rheem usually provides cutting-edge low-flow activation technology on most of its tankless electric water heaters. With regard to the RTE 13, the minimum water flow rate needed to activate its heater coils is 0.4 GPM. This is a quite small stream of water as compared to most electric tankless water heater models in the market yet it still functions pretty well.

2. Temperature Rise: The ability of any tankless water heater to perform well at optimum levels depends on the temperatures of the source water that comes into the unit. The colder the temperature of the incoming water, then the less water flow you should expect for the same heated water temperatures. The RTE 13 uses 55 degrees incoming water to produce 105 degrees of water from the faucet (a temperatures rise of around 50 degrees). As such, the RTE 13 water heater is limited to approximately 1.75 GPM.

3. Durability: The Rheem RTE 13 comes with a serial number once you purchase it. This minimizes the chances of buying counterfeit products that are sold as Rheem branded heaters. All the parts are made of high-quality materials that ensure that the unit lasts for a long period of time. In addition, Rheem provides a one-year parts warranty and 10-years warranty on the heat exchanger.

4. Energy Factor: The stated EF for the Rheem RTE 13 electric heater is 0.82. This is quite great when compared to the benchmark tanked electric tankless water heater’s Energy Factor range of between 0.75 – 0.95.

5. Installation: The Rheem RTE 13 water heater is normally rated for indoor use only and it should be installed vertically in dry locations where the water heater and water lines are generally protected from freezing. Rheem Company also recommends that the unit should be installed as close as practical to the place where you expect great demand for hot water.

Pros & Cons


  • Rheem RTE 13 electric heater is Energy Star certified
  • Its compact size usually makes it perfect for those who are living in small houses.
  • The space-saver profile also makes it quite easy to mount.
  • Since the unit only runs and heats when it’s in use, it doesn’t shoot your electric bills up thus making it an economical product.
  • It usually delivers greater value more than what you expect from its actual cost which makes the water heater a worthy unit to purchase.
  • The model is very efficient in producing adequate hot water for family use.


  • In order to extend further the life of this water heater, some homeowners would have loved more explicit details about how the tankless water heater can be maintained properly. Even though many agree that the construction of the unit is sturdy enough, basic maintenance is not generally enough for maintenance thus adding up some extra maintenance costs.
  • The unit’s performance has shortcoming mainly due to its inability to supply adequate power to the electric water heater. Thus, it’s very important that you understanding the power requirements of this machine so as to ensure that you’re getting its optimum performances.
  • Just like the process of setting up an electric appliance, its installation process remains to be potentially dangerous for individuals without experience. As a result, you might have to seek professional advice for installation.

Customer Reviews

Users of Rheem RTE 13 Tankless Water Heater are generally pleased with their purchases and the unit works exactly as it promises to work. Although some individuals commented on lack of clear instructions concerning setting it up, installing and using it, the water heater works almost flawlessly once you’ve figured out everything. Even in the cold climates, it will still keep your water hot even without costing much as compared to gas and oil-powered boilers. The size is great and it lets you install the unit wherever it’s convenient. You can use the unit in the shower, in the kitchen, in the laundry room or in powder rooms. Regardless of where it’s placed, it still works perfectly.

Indeed this is a surprisingly powerful electric water heater in a very small package. Rheem RTE 13 water heater is a reliable and affordable replacement for the energy-wasting tanked heaters. The best application of the model is for the point-of-use installations with relatively short water runs to less than 3 fixtures. When installed and adjusted properly, the RTE 13 water heater can provide an unlimited supply of hot water for all the needs of an office, shop, camper or small household.


Overall, Rheem RTE 13 electric water heater delivers efficient and outstanding performance for such a very compact device. This makes it a worthy purchase. The positives from the model by far outweigh its downsides. Furthermore, the size and price of this heater are also hard to beat. To sum it up, Rheem RTE 13 is one of the best electric water heaters that you can get on the market today.


Weight: 7.35 Pounds

Dimensions: 7.2"x7.2"x7.2"

Type: Propane and Natural Gas

1 yr parts &10 yrs heat exchanger warranty

 Voltage: 240 volts 

Wattage: 13000 watts

Certification: Energy Star


Water Flow Rate  0.4 - 4.0 GPM 

Durability:  unit lasts for long period  

Energy Factor 0.82

Temp. Rise: 55° incoming water to produce 105° water

Indoor Installation

Indoor Installation

Indoor Installation

Pros and Cons

Economical Product

Compact Size 

adequate power to electric heater

Quite easy to mount.

Efficient for family use.

Add some extra maintenance costs.

Seek professional advice for installation


If you still have questions about Rheem RTE, please contact us.