Are you beginning to notice a decrease in your electric water heater’s efficiency? There are several things which could cause your unit to be less efficient, such as sediment build up.
It can also be caused by a broken or burnt out heating element.
If so, you’ll most likely have to replace the water heater element. But don’t worry, it’s usually an easy job. Replacing the element can save you the trouble of buying a new water heater and increase the efficiency of the one you have.
How Heating Elements Work
Electric water heaters use electric heating elements, whereas gas-powered units have gas burners. Most elements are made of steel wire with copper casing, and they heat up as an electrical current passes through them.
Elements will generally heat up to two degrees warmer than the water, to keep it at the right temperature. Each element is controlled by a thermostat.
There are two heating elements in a tank: the upper and lower. The lower is the one that does most of the work, heating the water as it enters the tank. The upper element only works when demand is high.
Electric water heaters tend to be less energy efficient compared to gas-powered units, and take a little longer to heat. There’s also a significant amount of standby heat loss, although new insulation technologies have improved this on modern heaters.
When buying a new electric water heater, look for its thermal resistance rating (R-value). A high R-value means less standby heat loss. Models with an R-value between R-12 and R-25 are generally recommended by experts (1).
The cost of running an electric water heater is also higher than gas units, due to higher electricity bills compared to natural gas.
What Causes Water Heater Elements to Stop Working?
There are several things that can damage a water heater element. Some can be fixed by cleaning, but others require replacement.
1. Mineral Buildup
Depending on the quality of your local water, it might have a significant amount of minerals in it — this could be calcium or magnesium. And more minerals means harder water (2).
While the minerals won’t harm you or your family, they can damage your water heater. As the cold water gets heated, the minerals dissolve in the water and settle within the tank. They’ll also settle around the heating elements, most often the lower one.
When sediment builds around the element, it insulates it, forcing it to work harder. This can cause the element to burn out or simply stop working. Regular flushing of the tank can get rid of sediment and other buildup.
2. Power Surge
Heating elements have a specific voltage rating, if it goes above what it can take, the element will burn out. This can happen when there’s a power surge from the utility company, or even during lightning storms.
As the water heater heats the water, air pockets sometimes occur. They can also occur if the tank is not filled properly.
A water heater element can burn through its copper casing in less than a minute if it’s not immersed in water. If there are a lot of air pockets at the top of the tank, the upper heating element will be exposed. As it tries to heat, it will quickly burn through its casing, resulting in the element failing.
Heavy gauge wires deliver electricity to the heating elements. If the connection is bad or damaged, it can cause trouble. For example, sometimes a wire can come loose from the terminal — this will stop the element from working.
It can also result in arcing or cause a wire to ground through the metal tank, which is very dangerous.
Water heater elements are designed to heat in water. If the tank is empty or only has a small amount of water in it, the elements can dry-fire. As above, the elements will burn through their casing.
A dry-fired element can fail within 30 seconds. Dry-fire most often happens in newer models.
How Long Do Heating Elements Last?
It’s difficult to determine how long water heater elements will last. It all depends on how well the unit is maintained. Remember, the heating elements are working around the clock to heat the water.
Low wattage heating elements generally last longer than high wattage ones, because the heat is spread over a greater surface (3).
Regular flushing and maintenance checks can help to extend the life of the water heater and its elements. You should keep in mind that heating elements are similar to lightbulbs — they’ll burn out at some point.
How Can You Tell If a Heating Element Is Bad?
If you suddenly experience no hot water, it’s most likely due to the elements. It’s usually the lower heating element which burns out first. To know if the problem is from an element, you need to test them first.
Turn off the power by either unplugging the unit from the wall or turning it off by the circuit breaker. Remove the wires connected to the element and push them aside. Unscrew the hardware using a screwdriver, then slip the wires out and bend them out of the way.
Set your multimeter to measure ohms (resistance), and set it to the lowest reading scale. Using the multimeter, touch a probe on each screw on the element. No reading or maximum reading means the element is bad (4).
A reading of 10 to 16 ohms is normal. Check the wattage of your element on the plastic block located between the two screws.
To find out if the element has shorted out, touch one probe to a screw and another to the bare metal tank. If you get any reading or notice any movement of the needle, the element has shorted out. You can check each screw on both elements using this method (5).
How to Replace a Water Heater Element
There are two main types of elements: flange and screw-in. Screw-in is the most common. They’re also fairly easy to attach — you’ll need a water heater element wrench.
1. Turn the Power Off
Since you’re dealing with an electric appliance, it’s crucial you turn the power off before doing anything. Cut off the power supply at the circuit breaker. If you’re still unsure whether the power is off, you can use a multimeter to check the wires.
2. Drain the Tank
Make sure you first shut off the cold water valve located at the top of the unit. Then you can attach a garden hose to the drain at the bottom and open the drain valve. To drain the tank completely, turn on the hot tap closest to the heater.
You can drain the tank enough to expose the broken element, or you can drain it completely to get rid of sediment. Many experts recommend flushing the tank whenever you do repairs.
3. Remove the Water Heater Element
Open the access panel and remove the plastic safety cover, if your unit has one. Disconnect the element wires — you can do this to both elements to save time.
If your heating elements are screw-in type, you have to use the specialized wrench. An element tool is a socket which fits the hexagonal end of the element. It’s got holes on both sides where you can insert a screwdriver shaft.
This makes it easy to unscrew the element as you turn it counter-clockwise. Older elements may be more difficult to turn. When the element is loose, lift it out of the tank.
If your unit uses flange-type elements, you’ll have to unscrew four bolts to get it loose. Once the bolts are loose, lift the element out.
4. Replace the Element
When you replace a water heater element, it’s important to also replace the rubber gasket. This will prevent future leaks.
The rubber gasket is placed over the threads in a screw-in element and it’s placed around the base of a flange.
Once the rubber gasket is in place, you can proceed to install the element. First, fit it straight into the tank and hand tighten it. Then use the tool to screw it in place going clockwise. In a flange type, secure the four bolts.
5. Refill the Tank
Start by turning off the drain valve at the bottom of the tank. Then turn on the cold water inlet valve to allow new, fresh water to enter the tank.
If you’re worried about air in the tank, leave the faucet running. It will be sputtering as the tank fills, but when you get a regular flow the tank should be air-free. Once you get a good flow, turn off the faucet.
Before you turn on the unit, you need to reconnect the wires. Turn on the circuit breaker and inspect the tank for any leaks. Once everything looks good, attach the safety cover and access panel.
Let the water heater stand for about an hour to heat the water. Check to make sure it’s heating properly, and again, check for leaks. Contact your local plumber if you experience any difficulties.
How Do You Get a Stuck Water Heater Element Out?
Removing a water heater element shouldn’t be too difficult, however, they can get stuck. This is usually due to heavy sediment buildup.
You can use a descaling or de-liming solution to scrub the area around the element. We recommend using an old toothbrush because of its size. Gently move the wires out of the way before starting.
You can also use vinegar and water to scrub the element loose, and if it’s still not loosening, you can try soaking it in the solution. Use the wrench tool to try and further loosen it. If it’s persistent, you might need to use a hammer to tap the handle of the socket.
How Much Is a New Water Heater Element?
When you first notice a decrease in hot water, you might be thinking it’s time to replace the whole unit. If the problem is due to a burnt-out element, it can easily be fixed.
Replacing a heating element can cost around $150 to $200, which is a fraction of the cost of a new water heater.
Choosing to replace a water heater element can also save you money on labor since you don’t need to hire a plumber.
Replacing a water heater element is inexpensive compared to replacing the whole unit. Several factors can cause an element to fail — including sediment buildup, an empty tank, and electrical surges.
Luckily, replacing an element is straightforward. Just remember it’s essential to first turn off the power — electric water heaters use a high voltage, which can cause electrocution.
While you’re at it, we highly recommend that you also take the time to flush the tank of any sediment while doing any repairs. This will pay off in the long run.
Have you had to replace a water heater element before? What made things easier for you? We’d love it if you shared your thoughts and tips below.