Rheem is a renowned manufacturer of tankless water heaters (electric and gas). The Rheem RTEX series gets top marks from consumers all over the world due to its space-saving design and efficiency. This energy star certified unit supplies warm water instantly on demand and the unit’s energy saving feature will let you reclaim both the unit & installation costs within 17 months.

Rheem RTEX 18

The Rheem RTEX 18 model is equipped with a rugged copper and brass heat exchanger, which can withstand harsh water conditions. This heater ensures longevity, compactness and usability because its installation process is simple and it is slim and light weight. Due to its space saving design, you can install it at any nook and corner. Since RTE 18 heats water only when demanded therefore, its energy consumption is very low. Additional convenience is offered by its on-unit control system that allows easy temperature adjustments. On average this tankless water heater provides up to 5.0 GPM water and this unit is appropriate for two bathrooms in hot weather and one bathroom during cold climate. It is an ideal choice as a point-of-use application and perfect choice for homes, condos, apartments, hospitals, offices, boats, hotels and restaurants.

Features

  • Modulating power and On-Unit temperature controlling feature
  • Brass/Copper heat exchanger
  • Standby mode
  • LEDs indicate active element
  • Regular 1/2inches water connectivity
  • Around 3.51GPM constant flow of water guaranteed at 35degree Fahrenheit
  • Suitable for two bathrooms during summers and one bathroom during winters
  • 18KW heater requires a 240V electrical connection, two 40amp circuit breakers and 8gauge copper wiring
  • Energy efficient heater that warms water only when demanded
  • Space saving and light weight product
  • One year parts warranty, ten years heat exchanger warranty

Pros

  • Highly energy efficient because it heats water when you demand it and therefore, it can reduce your regular electricity bills
  • Maximum flow rate offered is % gallons per minute, which is outstanding
  • On-Unit controlling feature helps in adjusting temperature
  • Easy to install and stylish design that fits virtually anywhere
  • This is a very reliable heating solution because there are no apparent complaints about leakage

Cons

  • This heater is not as easy to be installed by a novice simply because the unit doesn’t come with a user manual
  • Warranty is insufficient and many users complain about the short life of the heater and poor quality parts
  • Consumes lot of energy and while it is operating other energy consuming devices such as light bulbs start flickering
  • It is advertised that this model can supply hot water to two bathrooms but in reality if both shower and sink are in use then water becomes cold sooner than expected

Specifications

Assembled Depth3.25″
Assembled Height10.50″
Assembled Width11.25″
Water Connection Size1/2
Amperage (amps)75
Electric Product TypePoint of use
Finish FamilyGray
Amperage12.5
Color FamilyBlack,Blacks
Flow Rate @ 35 F Rise (gallons/min)3.51 gal (US)/min
Flow Rate @ 45 F Rise (gallons/min)2.73 gal (US)/min
Maximum Temperature (F)125
Minimum Activation Rate (gpm)0.4
Indoor/OutdoorIndoor
Power/Fuel TypeElectric
Indoor/OutdoorIndoor
Fuel TypeElectric
Wattage (watts)1500
Product Weight (lb.)12 lb
Residential/Commercial/industrial UseResidential or Comercial
Modelrte 18
Water Connection LocationSide
Wattage (watts)18000

Ideal Use

This tankless water heater does its job well but finding its parts becomes a bit difficult after a while. Another drawback is that it requires two 40amp breakers. This makes it a bad choice if saving energy is your top priority as the unit will consume a lot of energy. Buy it if you require plenty of hot water or have a bigger family.

Rheem RTEX 13

The Rheem RTE 13 is a powerhouse when it comes to performance as it can heat upto 4gallon water per minute. It has been designed for indoor usage primarily homes, condos, offices, labs and/or hospitals.

Features

  • On-unit heat regulation
  • LEDs direct active element
  • Contains Standby mode
  • Standard 1/2″ water link
  • Durable brass/copper heat exchanger
  • Modulating power

Pros

  • This tankless unit is very compact and space-saving.  Fits almost anywhere
  • The unit doesn’t store water inside and supplies hot water within seconds once the switch is turned on.
  • Heats up to 4gallons water per minute, which proves its efficiency
  • Energy-saving mechanism minimizes electricity bills
  • Doesn’t require venting
  • Modulating heat exchanger prevents standby heat loss

Cons

  • The unit is not feasible for being used by large families because it cannot fulfil high demand for hot water
  • Additional components are required to be bought to enhance the unit’s functioning
  • It requires extra wiring and a 60amp circuit breaker

Installation and Specifications

The heater’s compact size makes it easy to be installed just about anywhere. The installation process is simple and easy. You don’t need to assemble different parts before mounting the heater because it is a single unit. All that needs to be done is to mount the device on to the wall and connect the pipes for water supply.

Assembled Depth3″
Assembled Height10″
Assembled Width7.25″
Product Depth3″
Product Height10″
Product Width7.25″
Water Connection Size1/2
Amperage (amps)54
Electric Product TypePoint of Use
Finish FamilyGray
Flow Rate @ 35 F Rise (gallons/min)2.54 gal (US)/min
Flow Rate @ 45 F Rise (gallons/min)1.97 gal
Fuel TypeElectric
Indoor/OutdoorIndoor
Maximum Temperature (F)125
Minimum Activation Rate (gpm)0.4
Minimum Temperature (F)0
Point-Of-UseYes
Product Weight (lb.)8 lb
Residential/Commercial/industrial UseResidential or comercial
ModelRTE 13
Voltage (volts)240
Water Connection LocationSide
Water Heater FeaturesNo Additional Features
Wattage (watts)13000

Common Problems

Rheem RTE 13 is an efficient model and ideal for domestic usage but a few concerns are still there. Some of the units have inherent technical faults that potentially affect its performance. Another issue is that you require at least 3inch extra copper tubing that has to be passed on both the sides of the unit. If you have plastic piping then you will have to change it as well. Moreover, you need to have electricity service that can handle a 240v/60amp circuit breaker. The user manual states that unit requires 6ga wire but in reality it utilizes 8ga.

Ideal Use

This water heater is perfect for small families. For larger homes it is also feasible but you will have to install two units to satisfy high demand. The energy-saving and eco-friendly feature of the unit makes it highly suitable for every household. Moreover, it is not very expensive in comparison to gas tankless units or tank heaters and you can easily reclaim the expenses afterwards by reducing monthly electricity bills.

Rheem RTEX 08

Rheem RTEX 08 is an excellent unit for being sued as a point-of-use application and for obtaining hot water whenever required. It is a very compact, light-weight and efficient water heater that can potentially lower your regular energy bills to great extent. It is one of the leading electric water heating units and no other model offers such a wide array of useful features like it does. Here are some of its prominent features:

  • On-Unit control of temperature
  • LED equipped with standby mode and active element
  • 1/2inch water connection
  • Reliable heat exchanger created from brass/copper
  • Power modulating

Just like the case with all Rheem tankless heaters, RTE 8 also doesn’t require T&P valve. Its compact size makes it suitable for all sorts of locations such as condos, hospitals, homes, apartments and offices. It offers a 30degree F temperature rise and you can expect around 5GPM hot water.

Pros

  • Compact size and light weight saves storage space
  • Excellent as point-of-use application
  • Easy to mount and simplistic water connections through 1/2inch compression fittings
  • Modulating heat exchanger makes the unit energy efficient
  • Saves energy through the standby mode

Cons

  • Not suitable for large families
  • Unit loses efficiency if used by many people
  • Installation although is simple but requires additional wiring and pole breakers, which increases installation cost

Installation and Specifications

The unit’s Use & Care Manual comprehensively informs about the installation procedure. It gets installed fairly easily and quickly. Just mount the heater and an electrical junction box to the area you need to fit it. Plumb the unit into water pipe using the PTC (push to connect) pipe fittings. Flip-off the main breaker and run the 8-gauge wire between the RTE 8 and circuit breaker panel and tie it into the junction box using wire-nuts. Lastly, connect the wire to 240V/40amp breaker.

Assembled Depth3″
Assembled Height10″
Assembled Width7.25″
Product Depth3″
Product Height10″
Product Width7.25″
Water Connection Size1/2
Amperage (amps)38
Electric Product TypePoint of Use
Finish FamilyGray
Flow Rate @ 35 F Rise (gallons/min)1.76 gal (US)/min
Flow Rate @ 45 F Rise (gallons/min)1.37 gal
Fuel TypeElectric
Indoor/OutdoorIndoor
Maximum Temperature (F)125
Minimum Activation Rate (gpm)0.4
Minimum Temperature (F)0
Point-Of-UseYes
Product Weight (lb.)8 lb
Residential/Commercial/industrial UseResidential or comercial
ModelRTE 8
Voltage (volts)240
Water Connection LocationSide
Water Heater FeaturesNo Additional Features
Wattage (watts)8000

Common Problems

The unit is although being promoted as suitable for large families but in reality it can support no more than two persons at a time. You cannot perform multiple tasks simultaneously such as washing dishes and taking bath, which makes it not suitable for families that demand hot water very frequently. Conversely, response time is very quick and way faster than a gas tankless water heater since a gas unit takes at least 30sec to start warming water whereas RTE 8 takes just 15sec. It is an ideal point-of-use application for small family and must be bought if you want to replace gas water heater with an energy efficient electric one.

Ideal Use

Definitely go out and get a Rheem RTE 8 electric tankless heater if you live alone and have limited storage space at home. The heater will suffice for your use only and may also support one more person’s needs, but not at the same time. Installation is fairly simple but will cost a little for wiring and pole breakers. If you want to replace your old heater with a new one without too much demand on hot water supply then opt for this one.