The professional 24kw / 240 volt 5.9 GPM tankless electric water heater offers a continuous, endless supply of hot water. It saves space, energy, and money. Requires no venting. The sleek, compact size allows you to install the unit wherever you want, including under a sink or in a closet. Tankless electric units only draw energy when hot water flows, while traditional water heater tanks constantly draw energy to keep the water at the desired set temperature.