Rheem RTEX-18 18kW 240V Tankless Electric Water Heater with LED Display
Imagine never running out of hot water—ever. The Rheem RTEX-18 tankless electric water heater keeps the warmth coming, whether you're sudsing up in the shower or tackling a mountain of dishes. (And yes, it can handle your whole house if that's what you're after.)
Here's the kicker: it's smart enough to dial down the power when you don't need it, slashing your water heating bill by up to 50%. Who knew being energy efficient could feel so good?
Gone are the days of that hulking water heater hogging space. This little guy is 90% smaller than the old tanks, fitting snugly under sinks or wherever you've got a spare nook. Talk about a space saver!
Want to tweak the temp just so? The external digital control with its LED display lets you adjust with precision—down to the very degree. Because sometimes, 'lukewarm' just won't cut it.
And let's not forget the nitty-gritty: durable copper heating elements and straightforward 3/4 inch NPT connections mean installation is a breeze. No PhD in plumbing required.
General specs
- Brand: Rheem
- Model: RTEX-18
- Seller: Amazon
- ID: B01MR7Z39V
- Dimensions: 14.5"W x 18.25"H
- Wattage: 18000 watts
- Voltage: 240 Volts
- Maximum Flow Rate: 4.4 Gallons Per Minute
- Maximum Temperature: 140 Degrees Fahrenheit
- Heat Output: 18 Kilowatts
- efficiency: 99.8%
- Mounting Type: Wall
- Item Weight: 14.78 pounds
- First listed by seller: 3/24/25
If you are interested in more details, you can find full information on the seller's page.
Price History for seller Amazon
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| Brand | Rheem | Rheem | HNK | EcoSmart | Vestidos | GE |
| Model | RTEX-18 | RTEX-24 | D3548A11 | ECO 11 | GE06P08BAR | |
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| Price | $415.00 | $464.99 | $139.98 | $189.99 | $101.08 | $155.10 |
| Seller | Amazon | Amazon | Amazon | Amazon | Joom | Amazon |
| Update | Dec 6, 2025 | Dec 6, 2025 | Dec 6, 2025 | Dec 6, 2025 | Feb 5, 2026 | Dec 6, 2025 |
| Wattage | 18000 watts | 24 KW | 3500 watts | |||
| Voltage | 240 Volts | 240 Volts | 110 Volts | 120 Volts | ||
| Maximum Flow Rate | 4.4 Gallons Per Minute | 5.9 Gallons Per Minute | 1.9 Liters Per Minute | |||
| Maximum Temperature | 140 Degrees Fahrenheit | 131 Degrees Fahrenheit | 140 Degrees Fahrenheit | |||
| Heat Output | 18 Kilowatts | 24 Kilowatts | 140 Degrees Fahrenheit | |||
| Mounting Type | Wall | Wall | Wall | Wall or Floor | ||
| Item Weight | 14.78 pounds | 17.8 pounds | 4.29 pounds | |||
| Product Dimensions | 17.63"W x 18.25"H | 9.13"W x 7.59"H | 17.25"W x 17.75"H | |||
| Special Feature | LED Display | Temperature Lock, Dry Combustion Protection, Overheat Protection, LED Display, Low Water Flow Protection | Adjustable Thermostat | |||
| Maximum Operating Pressure | 150 | 6 Bars | 150 Pound per Square Inch | |||
| Is Electric | Yes | Yes | Yes | |||