• Description
  • Specification
  • Sizing & Installation
  • Replacement Parts

ECO 18 | 18kW Electric Tankless Water Heater

Perfect for a large apartment or townhome with 2 bathrooms


Ideal for a large apartment/townhome with up to 3 people. The ECO 18 is the mid-range model that can heat over 2.5 gallons per minute. So it can handle a shower and a sink in cool climates. In warmer climates, it can handle two showers and two sinks. Use the EcoSmart interactive sizing guide to find out which model is ideal for you.

ECO 18 Features:

  • Savings of up to 50% on water heating costs
  • The most advanced, self-modulating technology available, meaning the ECO 18 will adjust how much energy needs to be input based on how much hot water is needed
  • Stylish and advanced design that is pleasing to the eye
  • Digital temperature control in 1-degree increments allows control of hot water
  • Copper and stainless components designed for efficiency, durability and easy replacement
  • Compact size saves valuable storage space

ECO 18

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
Electrical Panel 150 Amps
HZ 50/60
Pipes fittings 3/4" NPT
Dimensions (in.) 17"H x 14"W x 3.75"D
Weight 11.25 lbs.
Exchanger Copper
Protection Thermal Auto
Temperature Control Digital
Activation flow: .25 GPM
Energy efficiency: 99.8 %
Certification: ETL Listed to UL 499 & CSA
Warranty Lifetime*


Installation of your EcoSmart tankless water heater requires certain wiring and electrical specifications. To ensure maximum performance and to maintain your warranty, it is recommended that you have a licensed professional install the unit. The sizing chart below is based off a 240 volt electrical service. If you do not have 240 volts or are unaware of your electrical service please contact our customer service team at 877-474-6473 for additional product sizing support.

Click here to download the installation manual


CB QC MEDLRG - $52.11

Control Board

Compatible with:

ECO 18, ECO 24, ECO 27 & ECO 36


ENC FMED - $28.70

Front Enclosure

Compatible with:

ECO 18


FSA QC MEDLRG - $18.84

Flow Sensor Assembly

Compatible with:

ECO 18, ECO 24, ECO 27 & ECO 36

HE 90240

HE 90240 - $41.07

Heating Element 9 KW @ 240V

Compatible with:

ECO 18, ECO 27 & ECO 36


TRC QC 1HE - $31.12

Triac 1st Heating Element

Compatible with:

ECO 18, ECO 24 & ECO 27


TRC QC 2HE - $31.12

Triac 2nd Heating Element

Compatible with:

ECO 18, ECO 24 & ECO 27


TRC QC 3HE - $31.12

Triac 3rd Heating Element

Compatible with:

ECO 24 & ECO 27

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