|Replacement Electric Water Heaters|
|Replacement Electric Water Heaters
If you have an older electric water heater, a new high-efficiency model can save a significant amount of money for years to come. The average life expectancy of electric water heater is 10 to 12 years. Next to heating or cooling, water heating is usually the largest energy user in the home.
High-efficiency electric water heaters usually have higher levels of foam insulation, some as high as R-19.
There has been no significant improvement in electric elements. Electric resistance heating elements in your tank transfer virtually 100% of their energy to the surrounding water as heat. There are higher-efficiency heat pump water heaters which operate at an efficiency of over 100%, and often over 200%. They transfer heat from the surrounding air, ground, or well water to the water in the tank. Check with your contractor or local electric company to see if a heat pump water heater is right for you.
If you use central air conditioning, consider a waste heat recovery unit, which reclaims the heat given off by the outdoor unit of your air conditioner to heat water. When the air conditioner is not running, the standard heating elements serve as a back-up. Ask your heating and cooling contractor to see if a waste heat recovery unit is right for you.
Water Heater Efficiency
The energy efficiency of a storage-type water heater is indicated by its Energy Factor (EF). This is a measure of the overall efficiency of a water heater. It is determined by comparing the energy supplied in heated water to the total energy consumption of the water heater. A higher Energy Factor indicates a more efficient water heater. The most efficient electric storage water heaters have Energy Factors between 0.94 and 0.96.
First Hour Rating
This is the amount of hot water that the water heater can supply in the first hour of operation. It is a combined measurement of how much water is stored in the water heater and how quickly the water heater can heat cold water to the desired temperature. Use this rating to compare hot water delivery capabilities of similar models.
What to Look For
Look for a well-insulated water heater. The better the R value of insulation on the tank, the more energy efficient it will be. The size of the heating elements (whether 3 kW or 4.5 kW) has no bearing on efficiency, only on the time it takes to reach the temperature set on the thermostat after hot water has been drawn off.