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Rheem 18kW 240V Tankless Electric Water Heater

4.4 out of 5 stars 1,001 ratings

$430.41
& FREE Returns
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Style: Heater
Heater
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Enhance your purchase

Brand Rheem
Color Gray
Style Heater
Power Source AC/DC
Item Dimensions LxWxH 18.5 x 14.5 x 3.5 inches

About this item

    This fits your .
  • Make sure this fits by entering your model number.
  • External digital thermostatic control with LED display (+/1 degree accuracy)
  • Most advanced self-modulation, adjust power to meet hot water demand
  • Durable Copper immersion two heating elements, field Serviceable. Flow Rate- up to 4.4 GPM
  • Simple installation – bottom 3/4 inch NPT water connections
  • Threaded for easy replacement, simple installation, digital temperature display
See more product details

Customer ratings by feature

Temperature Control
4.3 4.3
Easy to install
4.2 4.2
Energy efficiency
4.0 4.0
Value for money
3.8 3.8

Frequently bought together

  • Rheem 18kW 240V Tankless Electric Water Heater
  • +
  • Rheem RTG20220AB Webstone Tankless Water Heater Service Valve Kit, Clean Brass
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What's in the box

  • Fittings, Aerators

  • From the manufacturer

    Model RTEX-04 is a point-of-use water heater for a single faucet. Model RTEX-06 is a point-of-use water heater serving up to two faucets Model RTEX-08 is a point-of-use tankless electric water heater serving one shower. Model RTEX-11 is a point-of-use tankless electric water heater serving a shower & up to two faucets. Model RTEX-18 tankless electric water heater serves up to two showers & two faucets. RTEX-24 tankles electric water heater serves a small home with up to three showers & two faucets.
    RTEX-04 RTEX-06 RTEX-08 RTEX-11 RTEX-18 RTEX-24
    GPM (Max.) up to 0.9 up to 1.5 up to 1.95 up to 2.68 up to 4.4 up to 5.9
    Power Source 120V Electric 220V Electric 240V Electric 240V Electric 240V Electric 240V Electric
    Kilowatt (Max.) 3.5 kW 6 kW 8 kW 11 kW 18 kW 24 kW
    Fixtures Served (Max.) 1 Sink 2 Sinks 1 Shower 1 Shower, 2 Sinks 2 Showers, 2 Sinks 3 Showers, 2 Sinks
    Height 5-7/8" 5-7/8" 12-5/8" 12-5/8" 18-1/4" 18-1/4"
    Width 10-7/8" 10-7/8" 8-1/4" 8-1/4" 14-1/2" 17-5/8"
    Depth 2-3/4" 2-3/4" 3-5/8" 3-5/8" 3-1/2" 3-1/2"
    Ship Wt. 4.5 Lbs 4.5 Lbs 7 Lbs 8.5 Lbs 14.78 Lbs 17.8 Lbs
    Water Connections 1/2" NPT 1/2" NPT 1/2" NPT 1/2" NPT 3/4" NPT 3/4" NPT
    Breakers Required (1 x 30)AMP (1 x 30)AMP (1 x 40)AMP (1 x 50)AMP (2 x 40)AMP (3 x 40)AMP

    Compare with similar items


    Rheem 18kW 240V Tankless Electric Water Heater
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    Stiebel Eltron Tankless Water Heater - Tempra 36 Trend – Electric, On Demand Hot Water, Eco, White
    Rheem 8kW 240V Tankless Electric Water Heater
    Airthereal Electric Tankless Water Heater 18kW, 240Volts - Endless On-Demand Hot Water - Self Modulates to Save Energy Use - Small Enough to Install Anywhere - for 2 Showers, Evening Tide series
    Customer Rating 4.4 out of 5 stars (1001) 4.4 out of 5 stars (886) 4.6 out of 5 stars (323) 4.6 out of 5 stars (1301) 4.2 out of 5 stars (149) 3.9 out of 5 stars (113)
    Price $430.41 $280.00 $104.99 $663.75 $258.99 $299.99
    Sold By Amazon.com MWH2330 UR SUPPLY DIRECT Amazon.com Caracas Cauchos USA Sain Store
    Item Dimensions 18.5 x 14.5 x 3.5 inches 12.63 x 8.25 x 3.63 inches 4.25 x 1 x 5 inches 4.63 x 16.63 x 14.5 inches 12.6 x 8.25 x 3.63 inches 17.25 x 12.22 x 3.43 inches
    Number of Items 1 1 1 1 1 1

    Product Description

    Rheem 18kW 240V Tankless Electric Water Heater

    Product information

    Technical Details

    Additional Information

    Warranty & Support

    Product Warranty: For warranty information about this product, please click here. [PDF ]

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    Product guides and documents

    Important information

    Wattage

    18000 watts

    Bulb Voltage

    240 volts


    Customer Questions & Answers

    Customer reviews

    4.4 out of 5 stars
    4.4 out of 5
    1,001 global ratings

    Top reviews from the United States

    Reviewed in the United States on April 5, 2018
    Style: HeaterVerified Purchase
    Customer image
    5.0 out of 5 stars Greatest water heater!
    Reviewed in the United States on April 5, 2018
    I am so impressed with this water heater!! No clicking relays, just totally silent. Simply hot water at your choice of volume. You choose the temp setting and it takes it from there! We (two of us) have a dishwasher, kitchen sink, laundry sink, bathroom sink, and bathtub, all depending on this little guy, and we never have a shortage! The set temperature lights up when you open the valve somewhere. One thing I will tell you, because a bathtub faucet has no restriction like the sinks or even the shower head, the water flows through this heater faster than it can get the water up to your set temperature (I have it set at 130). I remedied this by turning the hot water valve partway off at the bathtub. This restricts the flow into the bathtub JUST enough to allow the heater to keep up, yet is not slow so as to be inconvenient.
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    204 people found this helpful
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    Reviewed in the United States on March 20, 2018
    Style: HeaterVerified Purchase
    199 people found this helpful
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    Reviewed in the United States on January 12, 2020
    Style: HeaterVerified Purchase
    Customer image
    5.0 out of 5 stars Works great for 2,500 sq ft home.
    Reviewed in the United States on January 12, 2020
    Very good unit. I can feel the Hot Water in about 1-2 minutes in the farthest bathroom. Great unit for a 2,500 sq ft 4 BDRM 3 BTRM House. When installing be sure to use suggested 8 AWG wire for dual 40 Amp Circuit Breakers. Also make sure to vent/open all of the faucets before powering on the unit. If not you can get a error code on the unit. Lastly the unit will only come on when you use the Hot Water, thus the savings $ on electricity, and the LED sceen that shows the temperature will only come on then. Very satisfied.
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    88 people found this helpful
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    Reviewed in the United States on January 21, 2019
    Style: HeaterVerified Purchase
    88 people found this helpful
    Report abuse
    Reviewed in the United States on December 8, 2018
    Style: HeaterVerified Purchase
    73 people found this helpful
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    Reviewed in the United States on April 23, 2019
    Style: HeaterVerified Purchase
    57 people found this helpful
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    Reviewed in the United States on October 4, 2019
    Style: HeaterVerified Purchase
    38 people found this helpful
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    Reviewed in the United States on October 14, 2017
    Style: HeaterVerified Purchase
    61 people found this helpful
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    Top reviews from other countries

    CGiguère
    4.0 out of 5 stars Bon produit, mais ce n'est pas fait pour tout le monde
    Reviewed in Canada on February 15, 2021
    Style: HeaterVerified Purchase
    15 people found this helpful
    Report abuse
    Amazon Customer
    1.0 out of 5 stars Poor service
    Reviewed in Canada on November 5, 2020
    Style: HeaterVerified Purchase
    4 people found this helpful
    Report abuse
    Tim Elgersma
    2.0 out of 5 stars Defective right out of the box.
    Reviewed in Canada on July 14, 2021
    Style: HeaterVerified Purchase
    One person found this helpful
    Report abuse
    Amazon Customer
    5.0 out of 5 stars Awesome, works great!
    Reviewed in Canada on April 1, 2022
    Style: HeaterVerified Purchase
    sheila
    2.0 out of 5 stars Dont buy if you have a winter season where you live.
    Reviewed in Canada on November 14, 2020
    Style: HeaterVerified Purchase
    One person found this helpful
    Report abuse