Rheem RTEX-18 Professional Classic Electric Tankless Water Heater Reviews

3.4 Rating 5 Reviews

Rheem RTEX-18 Professional Classic Series 18 KW, 240 Volt, 75 Amps, 7 Gallon Per Minute Indoor Electric On Demand Tankless Hot Water Heater

Professional Classic Energy efficient tankless electric indoor inline water heaters offer continuous/endless hot water quickly and on demand for single point-of-use such as sinks, showers or bathroom or multiple applications. This electric tankless water heater is able to provide isntant and endless energy effecient hot water for whole homes up to 1 - 2 bathrooms. These compact tankless residential electric water hot heaters are also great RVs, campers, mobile homes and travel trailers. Rheem's compact low profile design allow these small, yet highly powerful, eco freindly and money saving 7 gallon per minute point of use tankless water heaters to fit easily under kitchen and bathroom sinks and counters.

Performance Features:
On demand, consistent and endless hot water
99.8% Energy efficient
Robust copper immersion heating elements with brass top increases durability and are threaded for easy replacement
Simple Installation
Digital temperature display
External controls to adjust temperature in increments of 1°F*
External Digital Display shows outlet temperature
Durable Copper Immersion single heating element, field serviceable
Simple Installation 3 Foot electric cable included; Bottom 3/4" NPT water connections
Specifications
Weight:10.0000
Voltage:240V
75 Amps
Required Breaker: 2 40Amp
Wire Size: 8 AWG
Power: 18 kW
Energy Source:Electric
Water Connection:3/4 Inch
7 Gallon Per Minute Max Flow Rate

Applications
Water-Saver Shower Head 1.5 GPM
Standard Shower Head 2.0 GPM
Standard Hand Sink 0.5 GPM
Kitchen Sink 1 to 2 GPM
Bath Tub 4 GPM
Dishwasher 1 to 2 GPM
Washing Machine 1 to 1.5 GPM

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“Just stopped heating water … electricity flow (current) working ok … temperature display doesn’t stays on .. goes out after few seconds”

Helpful Report

Posted 2 years ago

I just looked up your order, it looks like it was placed back in 2019. Glad to hear you have gotten nearly 4 years of use without any issues. That said the unit is still under warranty. It has a 5 year warranty, so if you contact Rheem technical support at 1-800-432-8373 and it cannot be fixed with them and needs to be replaced, you will send me an email with a photo of the unit's rating plate, we will verify the claim with Rheem, and ship out a replacement. Please be by the unit when call tech support. They are there Monday - Friday from 7:30 AM - 4:30 PM CT.

Posted 2 years ago

Celynn Desfosses

Verified Reviewer

“I LOVE my water heater. It's small, efficient, and I NEVER run out of hot water.”

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Posted 3 years ago

Marek Stanczak

Verified Reviewer

“Because my water is so cold RTEX-18 can only deliver warm water for only one device at the time . Not good choice for a household with family .”

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Posted 4 years ago

Daniel Lebeouf

Verified Reviewer

“The tank failed and got water all in my house! I sent a warranty claim but never heard any response. I have sent pictures etc to show the product failed again i have yet to hear any response about the issue! Also i used the charts to decide what heater was right for my house but the unit never performed to our liking. It would barely put any water out if i would increase the flow it wouldnt heat the water up. Please contact me i'd love to share more detail.”

Helpful Report

Posted 4 years ago

I am sorry to hear that, but it sounds like there are a couple of issues. First it sounds like the unit was not installed properly for it to leak like that. There is no tank that stores water and then can explode or leak or something like that as it is a tankless unit that heats the water you are using as you are using it. Because of that it would not stop leaking if the unit was defective and did have a leak somewhere. If it is still leaking, I am sorry we never received any emails or calls from you. That said you would want to call Rheem technical support at 1-800-432-8373. If the unit is leaking or otherwise not working properly there will be no need to email them photos or anything like that. After talking with them, email me at RheemTanklessHeaters@gmail.com a photo of the unit's rating plate (the white sticker with the model and serial # on it) and the case # provide by Rheem and we will be sending out a new unit. That unit has 5-year warranty on the heating element and 1-year warranty on all other parts. Lastly, it is an RTEX-18, which is not really made for a whole home. The RTEX-18 is typically going to be used for a single shower, not even a bathtub in colder climates. It is important when sizing a tankless water heater to know what is the gallons per minute you need is, as well as the temperature rise, which is the difference between the incoming water temperature and what you want the outgoing water temperature to be. A tankless water heater never runs out of hot water, but if you are using more water than what it can heat at once it will not get as hot as you want it. That is why it is important to know the gallons per minute you need, and the temperature rise. Then use the temperature rise and flow charts to make sure the unit you buy will provide the temperature rise you want for your hot water demands. And if you have questions or need help determining your needed flow rate or temperature rise to call before buying. We are happy to help. It sounds like you most likely needed the RTEX-27 or RTEX-36. Even those units in colder climates are not going to be do much more than 2 showers or one bathtub at once. Typically for whole homes that will have multiple showers, and sinks on a time you want to go with a gas or propane unit if you can, especially if you live in a mild to cool climate.

Posted 4 years ago

“Had this unit for several months. My family and I love it. No more running out of or waiting 9n hot water because of a teenage girl taking endless showers. The ratings for use are a bit high and are closer to correct with low flow faucets.”

Helpful Report

Posted 5 years ago