Water heaters are familiar fixtures in most homes. They typically look like big metal cylinders, tall drums that are often consigned to a laundry room or basement.
Newer styles have some interesting features, like losing the tank completely in favor of water-on-demand, but the old, reliable water heater design that's most widely used in the today is really a pretty simple appliance; it's basically a drum filled with water and equipped with a heating mechanism on the bottom or inside.
