Ecosmart® ECO 27 POOL Smart Pool Tankless Pool Water Electric Heater 1 Phase 27 kW 240V. Ecosmart ECO 27 is one of the most powerful models from our full line of tankless water heaters, with the capacity to handle a large single-family home and is perfect for a large Roman-style and Jacuzzi tub or high demand of hot water between multiple applications, even in colder climates. In warm climates, the ECO 27 can run four showers and a sink simultaneously without running out of hot water