# optimal Opti 18kW 240-Volt 25-Year Warranty Electric Tankless Water Heater

**Brand:** [optimal](https://shop.coreranger.com/brands/optimal)
**Price:** $499–$729 · in stock
**URL:** https://shop.coreranger.com/product/optimal-opti-18kw-240-volt-25-year-warranty-electric-tankless-water-heater-331964101

## Options

- **Maximum Flow Rate (gallons per minute):** 2.5, 3, 3.7, 4.5

## Variants

| Variant | SKU | Price | Stock |
|---|---|---|---|
| 2.5 | 12 Opti | $499 | in stock |
| 3 | opti15 | $519 | in stock |
| 3.7 | opti18 | $629 | in stock |
| 4.5 | opti27 | $729 | in stock |

## Specifications

| Spec | Value |
|---|---|
| Kilowatt | 18 |
| Returnable | 90-Day |
| Smart Home | Smart Home Enabled |
| Works With | Proprietary App |
| Amperage (A) | 75 A |
| Part Warranty | 25 Year |
| Power Options | Hardwired |
| Remote Access | No Remote Access |
| Requires Hub? | No Hub Required |
| Indoor/Outdoor | Indoor |
| Wattage (watts) | 18000 W |
| Application Type | Residential |
| Efficiency Level | Super High |
| Number of Showers | 1-2 |
| Water Heater Type | Electric |
| Product Depth (in.) | 3.5 in |
| Product Width (in.) | 11.4 in |
| Smart Home Protocol | Wi-Fi |
| Product Height (in.) | 16.9 in |
| Product Weight (lb.) | 12 lb |
| Uniform Energy Factor | 0.99 |
| Water Heater Features | Digital Display,Freeze Protection,Leak Detection,Overheat Protection,Vacation Mode,Wall Mounted |
| Required Volt Connection | 240 volt |
| Voice Control Hub Required | No Voice Control |
| Certifications and Listings | ETL Listed |
| Water Connection Size (in.) | 3/4 |
| First Hour of Delivery (gallons/hr) | 211 |
| Flow Rate @ 45° Rise (gallons/min) | 2.72 gal (US)/min |
| Flow Rate @ 35°F Rise (gallons/min) | 3.50 gal (US)/min |
| Maximum Flow Rate (gallons per minute) | 3.7 |

## Description

The opti18 electric tankless water heater can replace a tank heater for the whole home, act as a point of use, or supplement a hybrid as a booster to extend hot water availability. Refer to the sizing map in the images to learn more about the model that is best for you. With its powerful 18kW heating system and one-of-a-kind ultrasonic design, this water heater is engineered for energy efficiency and space savings. Expert, in-house, customer support stands behind the industry leading 25-year warranty for reliability you deserve in a product meant to last. Set it and forget it to the exact temperature you desire for endless hot water with an accuracy of 1°.

• Electric tankless hot water heater provides endless hot water
• Lifetime guarantee with a best in class 25 year warranty
• Heater requires two 8 AWG wires, two 40 AMP double pole breakers