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Hot Water · Element ReplacementWater Heater Element Replacement
Water heater element replacement costs $200–$400 done and is the right repair when an electric tank is dry, under about 12 years old and has one burned-out or grounded element. A dead upper element leaves every tap cold; a dead lower element gives a short burst of hot water and then cold. The new element must match the wattage and voltage on the rating plate, and the tank must be completely full before the breaker goes back on.
An element is a resistance coil inside a metal sheath, screwed through the tank wall into the water, and it fails two ways. The coil can burn open, which reads as infinite resistance across the two screws with the wires removed, or the sheath can split and leak current to the tank, which reads as continuity from either screw to bare metal. Both tests are done with the breaker off and the circuit proven dead. A grounded element is replaced even if it still makes heat, because it is the one that overheats the tank and trips the reset.
The lower element fails far more often than the upper, and sediment is why. Hard water in Halton and Hamilton drops scale that flakes off the elements and settles on the tank bottom, and on well water in Carlisle or rural Flamborough it builds faster. Once the pile reaches the lower element, the coil sits in an insulating crust, cannot shed its heat and burns out. If we pull an element caked white, we flush the tank before the new one goes in and usually fit a low-watt-density element, which runs cooler along a longer coil and tolerates scale better.
Most tanks use a screw-in element with a one-inch thread and a rubber gasket, removed with a deep element socket; older tanks may have a bolt-on flange held by four bolts, and the two do not interchange. Wattage and voltage come off the rating plate, typically 3,000 or 4,500 watts at 240 volts. A higher wattage than the plate allows overloads the wiring and breaker the tank was installed on, and a 120-volt element on a 240-volt circuit burns out at once. The element glossary entry shows what the markings mean.
The step that ruins new elements is the refill. With the element changed, the cold supply is opened and a hot tap upstairs is left running until it flows steadily with no spitting air; only then is the tank full to the top. An element switched on in air instead of water overheats and fails within seconds, and the upper one is the one left exposed if the tank is short of full. Power goes back on last, and we clamp an ammeter on each element in turn to confirm it draws what its wattage says it should.
Signs an element has failed
- No hot water at any tap with the breaker on: the upper element, or the thermostat that feeds it
- A few minutes of hot water, then cool: the lower element is out and only the top of the tank is heating
- Recovery that has stretched from an hour or two to most of the day
- The red high-limit button keeps tripping, the mark of a grounded element heating without control
- Popping or hissing from the lower half of the tank as scale-crusted metal heats
How it works
Breaker off, covers off, voltage confirmed dead. Each element is disconnected and tested for resistance and for a path to ground, and the thermostats are checked so a good element is not blamed for their fault.
The tank is drained below the element, or fully for the lower one, the old element is drawn out and the opening cleaned. Loose scale is flushed through the drain valve and the new element goes in with a new gasket.
Cold supply on, a hot tap open until all the air is out, the gasket checked dry, then the breaker. We measure the current on the new element and leave the old one with you if you want to see it. To arrange the repair, send us the wattage from the label if you have it.
Common questions
Can I replace a water heater element myself?
The mechanical part is within reach of a careful homeowner; the risks are electrical and procedural. The circuit is 240 volts and must be proven dead with a meter, not assumed from the breaker label, and the tank must be full before power returns. A cross-threaded element or a pinched gasket leaks into the insulation where you will not see it for weeks.
Should the thermostat be replaced with the element?
Only if it tests bad or shows heat damage. A thermostat with welded contacts will cook a new element the way it cooked the old one, so we test both every time. On tanks over 8 years old many owners choose to do the matching thermostat while the cover is off; thermostat replacement explains that job.
What is a low-watt-density element and do I need one?
It produces the same wattage over a longer, often folded-back coil, so each centimetre of surface runs cooler. Cooler metal grows scale more slowly and survives being partly buried. On municipal water in Burlington or Oakville it is a sensible upgrade for the lower element; on a private well it is the one we recommend if you are tired of replacing elements.
Why did my new element burn out so soon?
Three usual reasons: it was powered before the tank was full and dry-fired, it was the wrong voltage or wattage for the tank, or the real fault was a thermostat or a loose wire and the element was an innocent part. Less often the tank bottom holds so much sediment that the new lower element was buried the day it went in.
When is an element not worth replacing?
When the tank is leaking from the shell, when the element port is so corroded the threads will not seal, or when the tank is past 12 years and the drain valve is blocked solid with scale. In those cases $200–$400 buys very little time, and the broader electric water heater diagnosis usually ends in a replacement quote.