If you need to have your water heater replaced, you should think carefully about what type of unit you want to install. Size and energy efficiency are important factors to consider. You should also think about how long you can reasonably expect your new water heater to last, as some units will have a much longer lifespan than others.

Average Lifespan for Tank and Tankless Water Heaters

Most traditional or tank water heaters are more durable than they used to be. They tend to be much better insulated than older models. This means that they don’t have to run as often to keep the water hot, which helps to reduce wear and tear. However, the fact that tank water heaters constantly store water means that they will always corrode over time. This corrosion is the main reason why traditional tank units don’t last nearly as long as tankless water heaters.

On average, a tank water heater will typically last for anywhere from eight to 15 years. Although electric tank water heaters cost more to run, they will usually last a bit longer than gas tank units. Most gas and electric tankless water heaters, on the other hand, will typically last for a minimum of 20 years. With proper maintenance, some tankless units could even last for more than 30 years. Not only do tankless units not have the same corrosion issues, but their components are also easier to replace. If the heat exchanger, gas burner or electric heating element fails, you can usually have the part replaced and extend the life of the unit.

How Regular Maintenance Can Help Your Water Heater Last Longer

The biggest factor that will determine how long your water heater lasts is whether you keep it properly maintained. Tank water heaters require much more maintenance than tankless units and should always be flushed, inspected and serviced by a plumber at least once every year.

With a tankless unit, the main thing you need to do is have the unit flushed, cleaned and descaled once or twice a year. Limescale and mineral deposits will tend to build up on the heat exchanger, so it needs to be descaled to get rid of all of the deposits. If the heat exchanger is coated with a thick layer of limescale, it will greatly decrease the unit’s effectiveness. Limescale can lead to the water never getting quite hot enough. Even a small amount of limescale can decrease the unit’s efficiency by 30% or more, and this decreased efficiency will usually end up shortening its lifespan by quite a bit.

Tank water heaters need to be flushed regularly to get rid of all of the sediment that builds up inside the tank. Sediment buildup makes a water heater less effective and efficient. This leads to it running longer and more often and thus suffering more wear and tear.

Sediment will also often cause the lower heating element in an electric unit to wear out more quickly, requiring the heating element to be replaced. Sediment is a much bigger problem for gas water heaters. When the unit runs, the sediment can absorb a huge amount of heat from the gas burner. This can create hot spots at the bottom of the tank, which can weaken the steel and cause it to corrode more quickly.

Most water heaters have a steel tank that could easily corrode. To prevent this, manufacturers put a special glass or enamel coating on the inside of the tank that prevents the water from coming into direct contact with the steel. However, this coating slowly degrades over time, which is why tank water heaters also have an anode rod.

The anode rod is constructed of a steel cable that is coated with aluminum, magnesium or zinc. These metals are much more reactive than steel, which means that minerals in the water corrode the metal coating on the anode rod instead of reacting with the steel tank. This leads to the metal coating slowly being eaten away until all that is left is the steel cable, which is why the anode rod should always be replaced every three to five years. If you don’t have the anode rod inspected every year and replaced as needed, the tank will corrode more quickly and your water heater will have a much shorter lifespan.

Contact the Pros

If you need any water heater service in the Wingham or Hanover areas, Montgomery's Industrial Services has you covered. We’ve been providing professional plumbing services for more than 30 years, and we also offer expert electrical, heating and air conditioning services. Whether you need to install a new water heater or need any other home service, give us a call to schedule an appointment.

Paul Montgomery


Paul Montgomery is the president of Montgomery's Industrial Services. Paul has been in the business since 1992.
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