Sidfen Electric Tankless Water Heaters do not have a storage tank that you must heat 24 / 7, our tankless water heaters provide endless hot water on demand by using an copper heating element that the water flows past and heats up. Because you are not heating a huge tank of water all day every day for a 5 minute shower, you save money and save energy. Sidfen Electric Tankless Water Heaters help you in your quest to save energy, money and save space.