My electric water heater is 18 years old, but it still works. I want to try to reduce my water heating costs. What can I do to make my water heater more efficient?—Sandi T.
New water heaters are more energy efficient than older models, but with today’s economy, many homeowners simply don’t have the money to replace an older, less efficient water heater. I have lived in the same all-electric house for 22 years—I still have the same water heater as when I moved in. But I have still been able to make it as efficient as possible.
Electric water heaters are very simple devices. There are generally two electric resistance heating elements, top and bottom, in the water tank. The bottom one is used the most to keep the tank water hot. When the tank starts to run out of hot water, after many long showers, for example, the top element kicks on to supply hot water faster.
From the standpoint of using electricity to heat the water, all electric water heaters have practically 100 percent heating efficiency. All the electricity used does actually heat water because the heating elements are submerged. The difference in the overall efficiency and your water heating costs is determined by how much heat is lost from the water tank.
The efficiency of most older water heaters can be increased by adding insulation to the outside of the tank. You can easily test your water heater tank to see if it needs more insulation. Put the palm of your hand on other metal objects in your utility room to get a sense of their temperature. Next, put your hand on the water heater tank near the top and then on the top. I bet an 18-year-old water heater will feel significantly warmer. You are feeling the heat that the tank insulation is losing.
You can purchase water heater insulating jackets at most home center stores. These wrap around the tank and cover the top.
Old water heaters typically do not have heat trap fittings in the inlet and outlet pipes, whereas new water heaters do. Hot water, because it is less dense than cold water, naturally circulates up into the section of the pipes above the water heater. There, the hot water loses heat and drops back down. This continuous convection current wastes energy. Put tubular foam insulation over the pipes immediately above the tank, or have heat trap fittings installed in your old tank to stop this.
Although it is not as important with an electric water heater as it is with a gas one, every several months, drain a gallon of water from the valve at the bottom of the tank. If you have never done it before, you will likely see a lot of sediment come out.
Check the temperature of the hot water at the kitchen faucet. You will find covers on the side of the water heater, which cover the heating elements and the thermostats. Switch off the circuit breaker and adjust the thermostats. Switch the power back on and let the temperature stabilize. A target temperature of 120 degrees is adequate. Higher temperatures cause more heat loss through the tank insulation.
Install a water heater timer to switch it off, typically during the daytime when at work. With adequate insulation, the water stays reasonably hot. Set the timer so it comes back on late at night. This helps your electric cooperative control its peak demand. Check with your cooperative about incentive programs for maintaining your old water heater or buying a new one.