EcoSmart ECO 18 is an 18-kilowatt on demand electric tankless water heater ideal for providing hot water for apartments, condominiums, townhomes and other whole home applications. It can provide between 1.8 and 4.3 gallons-per-minute depending on the inlet water temperature. To select the best solution for your hot water needs, please refer to the electric tankless hot water heater sizing guide. With EcoSmart you will be happier knowing the warm water you expect is available endlessly, consistently, and on-demand, allowing you to reduce your water and energy waste. Now that feels warm all over! EcoSmart - Sharing the Warmth.