Electric storage tanks are the most common type of water heater. As the name suggests, these consist of an insulated tank in which water is heated and stored until needed, then emerges from a pipe on top of the water heater. Electric water heaters also contain a temperature and pressure-relief valve, which opens if either exceeds a preset level. Electric storage tank water heaters range in size from 15 gallons (smaller point-of-use tanks) to 120 gallons (larger storage tanks), depending on your needs.
An electric water heater can be used mostly anywhere; whereas a gas water heater is usually installed in a home that already uses gas. Water heater tanks traditionally come with a 6 to 12 year leakage warranty, depending on the size, make and model of the unit selected. This leakage warranty protects the homeowner against certain water heater malfunctions during the warranty period.