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EcoSmart ECO 18 Electric Tankless Hot Water Heater 18kW 220-240V

Original price $495.00 - Original price $499.95
Original price
$495.00 - $499.95
Current price $495.00


EcoSmart ECO18

EcoSmart Eco 18 Electric Tankless Hot Water Heaters let you enjoy endless hot water when you want it, only when you need it. Go Tankless and Save.

These water heaters are the most powerful Smart Technology electric tankless units in the market today. They are configured for climates with incoming water temperature that ranges from 45 to 60 degrees Fahrenheit.

How to choose your water heater model

Step 1: Add up the flow rates of all the water use points that you expect to simultaneously use. It does not matter whether your home has 2 showers, 4 sinks, a dishwasher and a clothes washer. What only matters is which of them you expect to run at the same time. See Chart A.

Step 2: Determine your coldest incoming water temperature of the year.

Step 3. Take your info from Step 1 and 2 and look up the info on Chart B.

Step 4: Ensure you have sufficient electrical service. See "Electrical Requirements" chart below.

Chart A

Flow rate guidelines for various hot water applications.

This chart is based on the use of water saver showerheads rated at 1.5 GPM and water saver aerators for sinks rated at 1.0 GPM. The number of showerheads and sinks next to each model reflects the model unit's capacity to make hot water simultaneously with the unit's temperature control set to 105°F. Note: The shower temperature that most people prefer is between 98°F to 105°F.

 EcoSmart Eco 18 Electric Tankless Hot Water Heater, Medium

Chart B

Inlet Water
Temperature →
40°F 45°F 50°F 55°F 60°F 65°F 70°F 75°F 80°F
ECO 8 .85 GPM .90 GPM 1.0 GPM 1.1 GPM 1.2 GPM 1.4 GPM 1.5 GPM 1.8 GPM 2.2 GPM
ECO 11 1.35 GPM 1.45 GPM 1.6 GPM 1.8 GPM 2.0 GPM 2.2 GPM 2.5 GPM 3.0 GPM 3.5 GPM
ECO 18
(this page)
1.9 GPM 2.0 GPM 2.2 GPM 2.4 GPM 2.7 GPM 3.1 GPM 3.5 GPM 4.1 GPM 5.0 GPM
ECO 24 2.5 GPM 2.7 GPM 3.0 GPM 3.3 GPM 3.8GPM 4.1 GPM 4.7 GPM 5.4 GPM 6.5 GPM
ECO 27 2.8 GPM 3.1 GPM 3.4GPM 3.7 GPM 4.2 GPM 4.8 GPM 5.2 GPM 6.1 GPM 7.3 GPM

This chart presents the flow rates at each inlet temperature with the unit's temperature control setting at 105°F.


Voltage 240
Phase Single
KW 18 kW
Elements 2 x 9 KW @ 240
Amperage Draw 75.0 Amps
Required Breaker 2 x 40 DP
Required Wire 2 x 8 AWG
Electric panel 150 Amps
HZ 50/60
Pipes fittings 3/4" NPT
Dimensions (in.) 18" x 14" x 3.75"
Weight 11.25 lbs.
Exchanger Copper
Protection Thermal Auto
Temperature Control Digital
Activation flow rate 0.3 GPM
Minimum PSI 25
Maximum PSI 150
Energy efficiency 99.8 %
Certification ETL Listed to UL 499 & CSA
Warranty Lifetime on exchangers, electronics, and elements.
(5 years outside of continental US and Canada)

Electrical Requirements

Before you purchase an EcoSmart, please make sure that your home has sufficient electrical capacity to run it. Refer to the following chart for electrical requirements:

Model Recommended
Maximum Amperage
@ 240 V
Recommended Household
Electrical Service
Recommended Minimum
Wire Gauge
ECO 27 3 x 40 AMPS DP 112.5 AMPS 200 AMPS 3 x #8 AWG Copper
ECO 24 3 x 40 AMPS DP 100 AMPS 200 AMPS 3 x #8 AWG Copper
ECO 18 2 x 40 AMPS DP 75.0 AMPS 150 AMPS 2 x #8 AWG Copper
ECO 11 1 x 60 AMPS DP 57.0 AMPS 125 AMPS 1 x #6 AWG Copper
ECO 8 1 x 40 AMPS DP 33.0 AMPS 100 AMPS 1 x #8 AWG Copper
POU 6 1 x 30 AMPS 29.0 AMPS 100 AMPS 1 x #10 AWG Copper
POU 3.5 1 x 30 Amps 29.0 AMPS 100 AMPS 1 x #10 AWG Copper

Wire gauge and breaker size must meet all applicable provincial, state, local, and national electrical codes for your area. These are only guidelines that may apply to most installations. Some codes require use of an electrical sub-panel, especially when heater isn't mounted within the line-of-sight of the main electrical panel. Wiring should be sized to maintain a voltage drop of less than 3% under load.

If your home is already equipped with a large number of electrical appliances, it may require a larger electrical service than the one recommended above. The above chart contains only guidelines. Please consult with an electrician before placing an order.


Download Installation and Owner's Manual
Download Troubleshooting Guide for Electricians

Frequently Asked Questions ("FAQ")

Q1: How do I replace the heating elements on the ECO 18?
A1. Replacing the heating elements on the Ecosmart ECO18 tankless water heater is fairly simple. But since removing the water heater cover is necessary, and there is a risk of injury or death due to high voltage, Ecosmart recommends that a licensed electrician do the work. Here are the steps:

1. Disconnect power.
2. Remove cover.
3. Unscrew the two steel screws on the end of the element plug and remove the two wires.
4. Unscrew the element from the heating chamber. The ECO18 uses 2 elements, each screwed into its own heating chamber.
5. Tightly, securely screw in new elements and replace wires and cover.

The ECO 18 uses two heating elements which are available for purchase here.

Q2: How do the temperature dial and display work?
A2: When water is flowing through this tankless heater, the digital display on the front of the unit shows the water heating temperature that you have set using the dial. To set the temperature, start by turning on any water faucet. The digital display will light up and give you the current temperature setting of the unit. To increase this setting, turn the control knob to "Increase" or "Decrease" your temperature setting. You can set the temperature at any level between 80°F (27°C) and 140°F (60°C). To change the digital display from Fahrenheit to Celsius, simply press the control knob for 3 seconds. Most people feel comfortable showering or bathing at a temperature between 98°F and 105°F (37°C to 41°C). We recommend that you set the output water temperature of your water heater at either 105°F or 110°F (approximately 41°C or 43°C). This will ensure you have adequate hot water to meet all of your household needs while also maximizing your available water flow rate, reducing the risk of scalding to children and the elderly, and increasing the energy savings you achieve.

Q3: Can I install the ECO 18 outdoors?
A3: Ecosmart tankless water heaters are designed for indoor installation. Installation outdoors is acceptable only if mounted an enclosure that protects it from dust, debris, rain, splashed water, insects, and direct sunlight. It must not be installed where it may be exposed to freezing temperatures. If any moisture is inside it when it freezes, the warranty is void.

Q4: How much can I save with ECOSMART's Tankless Water Heaters?
A4: The primary difference between savings associated with storage tank heaters compared to tankless heaters is the amount of energy and time consumed during operation. An electric tankless water heater consumes more energy compared to a tank heater during its use, but it consumes energy for a drastically shorter period of time. The result is a reduction in water heating costs by up to 60%.

The image below contains a visual representation of the concept mentioned above using data taken from independent third party testers. It shows how the storage tank heater keeps drawing power even after the need for hot water has long ceased. In this example, the tank heater used energy for 34.5 minutes just for a 10-minute shower. It also used a total of 2.5 kWh, in comparison to the ECO 27 which consumed just 1.6 kWh. The steadiness in the data represented about the ECO 27 is also an accurate indication of how precise the Self-Modulating Technology is, allowing for very minimal differences in energy consumption.

 EcoSmart Eco 18 Electric Tankless Hot Water Heater, Medium

PSC (Product Safety Consulting, Inc.) is a product testing firm recognized internationally and accredited by several reputable organizations. PSC administered numerous tests that simulate daily hot water usage and then compared the energy consumption results between an ECO 27, the largest model available from ECOSMART, and a 40 gallon water heater from Rheem. Based on an average ten-minute shower consuming two gallons per minute, a 37% savings in energy consumption was confirmed with the ECO 27. This figure is based on usage comparison and does not take into account energy loss associated with Cycling Loss and Standby-by Loss which may be accountable for up to 20% energy loss. This loss included, the ECO 27 uses up to 57% less energy compared to a standard electric storage tank water heater.

Installation Help and Recommendations

We recommend that you have a professional tankless water heater installer review the above recommendations. Need an installer? Get 4 FREE Tankless Water Heater Installation Estimates Now. It's Quick and Easy!
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