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Opti18 | Optimal Smart Electric Tankless Water Heater | 208/220/240-Volt 18 Kw 3.7 GPM


25-Year Warranty
$649.00$699.007% OFF

Lifetime warranty. 18 kW electric tankless water heater provides efficient, continuous on demand hot water. WiFi compatible.

what’s the right heater for me?

Overview

The opti 18 is the only water heater with patent pending ultrasonic flow sensing technology providing quiet and efficient operation. With advanced power-modulation, built in diagnostics and wireless compatibility the Opti 18 heats to within 1 degree of set temperature. Heat up to 3.7 gallons per minute (gpm) to 105°F given an inlet water temperature of 72°F. It supports a 3-bathroom home in warm climates, or acts as a point of use in colder climates.

Check the map in the product images to see the opti 18’s flow rate capacity in your area. This model is not wifi enabled but compatible with wifi board upgrade.

Product Details

Technical specs:

electrical

  • 2x 8 awg wire
  • 2 x 40 amp dp breaker
  • 50/60 hertz
  • 18000 watts
  • 75 max amp draw
  • 208/220/240 volts
  • 99.9% efficient
  • 2 Elements

plumbing

  • 3/4" npt connections
  • 0.25 gpm activation
  • 150 max psi

Details

  • 16.9”h x 11.4”w x 3.5”d
  • Indoor Use / Wall Mounted
  • 25 year residential warranty - See link below for complete details.
  • ETL Listed / UL Listed / CSA Listed

Install + Care + Warranty

The Opti 18 comes with a 25-year residential warranty and a 5 year commercial warranty. COVERS ALL COMPONENTS. For more information on installation, best practices, and the warranty, please use the links below.

Delivery Info

Orders are typically processed within 1-5 business days of receipt. Please note that this timeframe may vary depending on the specific model and availability of your chosen tankless water heater.

Shipping Methods: We offer various shipping methods through reputable carriers like USPS, DHL, UPS and FEDEX. Shipping costs are calculated based on your order weight, destination, and chosen shipping method. You will see these costs reflected during checkout before finalizing your purchase.

Its Optimal

What else should I consider?

Smart Technology

Our heaters are not just smart; they're geniuses in the world of water heating.

Ultrasonic Innovation

Experience the future with our ultrasonic flow sensing technology.

Unmatched Reliability

Feel secure with the last water heater you'll ever need.

Space Saver

Don't let a bulky tank take over your space.

Cost Efficiency

Keep your money in your pocket where it belongs.

Energy Conscious

Join the green revolution with a staggering 99.9% energy efficiency rate.

Top 5 FAQs

All what you need to know

HOW CAN I FIND THE RIGHT TANKLESS WATER HEATER FOR MY NEEDS?
WHAT IS THE LIMITED LIFETIME WARRANTY COVERAGE?
HOW EFFICIENT ARE ELECTRIC TANKLESS WATER HEATERS?
ARE TANKLESS WATER HEATERS “INSTANTANEOUS”?
HOW MUCH CAN I SAVE WITH AN ELECTRIC TANKLESS WATER HEATER?

For more details, visit our product faqs

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Customer Reviews
5.0 Based on 8 Reviews
5 ★
100% 
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Filter Reviews:
SJ
03/14/2025
Sarah J.
United States

Amazing product! Fantastic customer service!!!

Extremely impressed!!! Such an amazing product!!! It was easy to install. There are no fluctuating temps like the last device we bought (AO from Lowes - don't buy - horrible product). This product keeps a steady temp all the time. It's made very well and each device is tested by the manufacturer before it's shipped, so if there are water droplets in the box, don't be alarmed. They also have fantastic customer service which is a major plus! We are in the rental business and are so happy to have finally found a company worth sticking with. We are now customers for life! :)

T
01/28/2025
Tom
United States

Great product

Bought this for our cabin, very easy install. We haven't had much demand yet but works great so far. We had a few questions and the support was phenomenal, guy on the phone was friendly and very helpful.

JM
12/16/2024
Jesse M.
United States

Quality Company = Quality Product

Easy Installation... I had zero issues with the product during installation. This was my first time doing such a project, so that speaks for itself. Quality components... all water heater screws and plumbing fittings are quality. I upgraded to better wall anchors than the ones supplied. Excellent Customer Service! You will see for yourself if you ever have to call ;) Highly recommended product! I am a very pleased customer.

AF
11/12/2024
Antonieta F.
United States

Best customer service!

I just had my tankless opti18 installed a couple of month ago. It is working well, I can say so far so good. This review, at this point is to emphasize in the excellent customer service I received from Ryan. Before I ordered the unit he answered all my questions, same during the installation. Every time I called I got him on the phone. He is knowledgeable and always went the extra like to assist me. I have not received this customer service in a long, long time. The plumber and electrician also appreciated his assistance and they liked the product. They are already recommending it. We still need to make the wall look nice. Thank you

Optimal Tankless Water Heaters Opti18 | Optimal Smart Electric Tankless Water Heater | 208/220/240-Volt 18 Kw 3.7 GPM Review
C
10/29/2024
Cristian
United States

Good investment

I recently renovated my apartment, and tired of seen a big tank water heater inside taking a lot of space , I decided to go tankless. After seen several brands and reading some bad reviews and problems with those offered by the major chain stores, something caught my sight, OPTIMAL 18. I bought it, installed it and got working perfectly, it does what its specifications describes and the best of all....their costumer service support team. I had some cuestions before installation and Ryan spent some time explaining and guiding what was the best option for my needs. I highly recommend this brand looking for tankless water heater.