Paperwork says it requires four 40 amp breakers or two DP 40 amp breakers. Max draw of 75 amps.

Rheem RTEX-18 18kW 240V Electric Tankless Water Heater, Small, Gray

Rheem RTEX-18 18kW 240V Electric Tankless Water Heater, Small, Gray

Q: will this supply two showers, washer and dishwasher for two people? (1000 sf house)

Hello- Sizing an electric tankless is very difficult. I always recommend that you call Rheem at 800-432-8373 to get a suggestion. I want to say this will only keep up with ONLY 1 source of hot water at any one given time. That being said, the RTEX-18 performance ( @240V )- 1.5GPM - 82degree rise 2.0GPM - 62degree rise 2.5GPM - 49degree rise 3.0GPM - 41degree rise So.... what it can keep up with all depends on: -the temp of water coming into the house -the flow rate of each faucet/shower head/washing machine/source of hot water -outlet temp desired I hope this helped :) Ben

Q: Rheem rtex-18 be big enough to heat water in my shop to wash my hands and perhaps take a shower in kansas city, mo?

Yes you could even go with the unit rtex-15 one smaller if that's it. Good luck

Q: how many breakers and what amp.

The RTEX-18 (240 Volt) requires (2) 40 amp breakers and 8 AWG wire.

Product ID: 724817007

Secure Transaction

Details

Brand
Rheem
Product Dimensions
36.8W x 46.4H
Special Feature
LED Display
Color
gray
Wattage
18000 W

⚡18kW high power output

💧Up to 4.4 GPM flow rate

🔆±1°C precise digital temp control

Frequently Bought Together

Rheem 18kW 240V Tankless Electric Water Heater, Gray

HYDRO MASTER Tankless Water Heater Service Valve Kit with Pressure Relief Valve 3/4-Inch IPS Isolator Clean Brass

3/4 Inch IPS Isolator Tankless Water Heater Service Valve Kit with Pressure Relief Valve, Clean Brass, 3/4 Inch Service Installation Valve for rheem,rinai,ecosmart,navien,noritz,takagi,bosch

Description

🔥 Instant Hot Water, Zero Wait Time ⚡

POWER THAT ADAPTS - State-of-the-art self-modulation technology dynamically adjusts power to match your hot water demand, maximizing efficiency.
FLOW THAT KEEPS UP - Delivers up to 4.4 gallons per minute, perfect for busy households craving instant hot water without delay.
COMPACT CONVENIENT - Small footprint with easy 3/4" NPT bottom water connection makes installation and replacement hassle-free.
DURABILITY MEETS PERFORMANCE - Copper-dipped dual heating elements provide long-lasting, reliable heat delivery for consistent comfort.
PRECISION AT YOUR FINGERTIPS - External digital control with LED display ensures exact temperature every time, eliminating guesswork.

The Rheem RTEX-18 is a compact, 18kW 240V electric tankless water heater featuring precise digital temperature control with ±1°C accuracy, self-modulating power for energy efficiency, and durable copper-dipped heating elements. It supports a flow rate up to 4.4 GPM and offers easy installation with a 3/4" NPT water connection, making it an ideal upgrade for modern homes seeking on-demand hot water without the bulk.

Specifications

Brand	Rheem
Model Number	RTEX-18
Product Dimensions	36.83 x 36.83 x 46.36 cm; 6.7 kg
Color	gray
Name List for Name Plates	Heater
Voltage	240 Volts
Wattage	18000 W
Laser Class	LED Display
Included Components	Fitting Aerator
Are Batteries Included	No
Model Year	2016
Item Weight	6.7 Kilograms

Have a Question? See What Others Asked

will this supply two showers, washer and dishwasher for two people? (1000 sf house)

How many amps

Rheem rtex-18 be big enough to heat water in my shop to wash my hands and perhaps take a shower in kansas city, mo?

how many breakers and what amp.

Common Questions

Are the products genuine and authentic?+

Yes, all products are sourced directly from authorized retailers in the US, UK, UAE and India. We maintain strict quality control processes and verify each product before shipping. All items come with applicable manufacturer warranties and are covered by our standard return policy.

How long does delivery take and is it reliable?+

Delivery times vary by destination country, typically ranging from 3-9 business days. Each order is fully trackable through our system. We handle all customs clearance and use reliable courier partners for last-mile delivery. You'll receive regular updates about your order status via email and our app.

What is Desertcart? Is it safe to order from?+

Desertcart is an international e-commerce platform operating since 2014. We securely process thousands of orders globally each day. Every product goes through our quality verification process before delivery, and we provide end-to-end order tracking, 24/7 customer support, and a comprehensive returns policy to ensure a safe shopping experience.

How is product pricing calculated?+

Our prices include the product cost, international shipping, import duties, customs clearance, and local delivery charges. We handle all customs and import procedures, ensuring there are no hidden fees upon delivery. PRO members receive additional benefits including free shipping.

Trustpilot

TrustScore 4.5 | 7,300+ reviews

Sneha T.

Received my product in pristine condition. Great service overall.

1 month ago

Fatima A.

Best international shipping I've ever tried. Worth every penny!

3 days ago

View all Trustpilot reviews

Shop Global, Save with Desertcart

Value for Money

Competitive prices on a vast range of products