Because it does not store hot water, a tankless water heater, also known as an electric instant water heater or an instant water geyser, differs from a storage water heater and other typical water heaters. Instead, it heats the water as you use it, giving you quick hot water whenever you need it. The way traditional water heaters work differs from how electric instant water heaters work. When you turn on the faucet, the water heater is activated by the flow of water. The heating elements are ...