According to the California Energy Commission, heating Water accounts for 25 percent of their average residential energy bill, and electric heaters generally cost more to use than gas ones. To compute your water heating bill, you want to know how many watts of electricity your water heater utilizes. That info is on the tag.
Locating the Label
The tag that shows the wattage of the heating element in an electric water heater is affixed to the side of the heater. It ought to be clearly visible, since it’s situated next to the panel you need to remove when changing the heating element, and that panel must remain accessible. The tag shows the operating voltage and the wattage of this element. If your heater runs on 240-volt power, it usually has two components, so you’ll see two values for wattage — one for each element.
One Element at one time
Water heaters running on 120-volt power have a lengthy recovery time, which is impractical for many households; 120-volt components consume 1125 watts, while residential 240-volt heaters use 4,500 watts. If a heater contains two components, people sometimes assume that they ought to include their wattage to obtain the total power consumption of the heater. This is not right, because both components don’t come on at the same moment. A heater with 2 components and a label that specifies a power use of 4,500 watts for every single element utilizes a maximum of 4,500 — not 9,000 — watts.