Do Electric Water Heaters Use a Lot of Electricity?
- Conventional electric water heaters consist of the familiar cylindrical storage tank connected to both water supply and electrical supply. Conventional electric water heaters automatically release water and refill following the use of a hot water tap. Ranging from approximately 20 gallons to 40 gallons in storage capacity, conventional water heaters must heat and consistently maintain the temperature of a large amount of water. Thus, conventional electrical water heaters use a large amount of electricity and are generally considered the least efficient of all electric water heaters. Although specific use varies according to a family's habits, research from the University of Colorado indicates that conventional units consume around 5000 kilowatt hours of electricity per year.
- Unlike conventional electric water heaters, tankless and on-demand heating units heat water only while a hot water tap remains open. When the faucet is in the open position, cold water runs through the unit's electric heating element and continues to the open plumbing fixtures. Therefore, tankless and on-demand systems heat only the water required for usage. For homes with average water needs, tankless and on-demand systems offer significant energy savings. However, tankless and on-demand units are generally more expensive than conventional water heaters and often produce only enough water to supply a single fixture at a time. According to the U.S. Department of Energy, tankless units might require 18 to 50 percent less electricity than standard tank units, depending upon a household's water usage.
- Like an air-conditioning system draws hot air from a space and returns cool air, an electric heat pump water heating system draws hot air, further increases the air's temperature and uses the air to heat water. Under certain conditions, electric heat pumps serve as a primary energy source for a water heater. However, electric heat pumps are commonly added to existing systems, such as conventional or tankless systems, to reduce energy consumption. Electric heat pump systems are generally more efficient than conventional tank units.
- A solar hot water heating system harnesses the sun's heat to warm water. Solar hot water systems often work in conjunction with a standard electric water heater. Common solar hot water systems consist of roof-mounted panels, pipes or storage tanks. Specially designed to capture and retain heat, solar hot water systems preheat the electric water heater's water supply and significantly reduce the electric unit's heating load. Although solar systems carry a high initial cost, they offer substantial long term savings. According to the U.S. Department of Energy, solar water heating systems can cut a standard household's water heating costs by roughly 50 to 80 percent.