Something basic and often taken for granted, water heaters are an important part of the home that the homeowner should pay attention to. Generally speaking, water heaters are basically insulated vessels to heat and keep water warm for use in the home. Water enters the home through pipes and travels to the base of the tank. At the base of the tank is either a gas burner or electric heating element, which will heat the water. Temperature is maintained with a thermostat that can be adjusted. All water heaters should be properly vented and have a pressure safety valve.
Check out the full guide here:
Water Heaters – A Quick Guide