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Building Science by Norman Aceron Garcia

Water heater lifespan

by Norman Aceron Garcia

water heaterA typical water heater has a lifespan of about 10 to 12 years. Careful consideration of the factors that affect its lifespan can provide a homeowner with information on the likely cost of replacing the water heater. These factors include: the installation procedure, usage volume, quality of construction, and maintenance.

A water heater must be installed upright. If it is installed on its side, it will be subjected to structural stress due to inadequate support for the heater and its pipes that could cause premature failure. Water heaters must be installed in well-ventilated areas, not just for fire safety and nitrous oxide build up concerns, but also because inadequate ventilation can shorten the water heater’s lifespan. A water heater must not be installed in flood-prone areas because water can rust the exterior and pipes, which decreases the efficiency and life expectancy of the unit. A water heater is best installed in an easily accessible location for maintenance. It must also be easily noticeable for health-hazard and fire requirements.

The volume of water used largely governs the lifespan of the water heater. The water heater will have to work harder to heat the water if the volume is large. Moreover, greater water volume also magnifies the corrosive effect of water. Just like most household components and systems, you get what you pay for in a water heater. Cheaper units usually have shorter lifespan, whereas expensive ones last longer. A good sign of a quality fabrication is its warranty. Longer warranties generally indicate superior manufacturing quality, with nine and 12-year models normally having thicker insulation and bigger or higher-wattage heating elements. Water heaters with bigger heating elements and anodes have much better resistance to scum or mineral build up.

Also give attention to the water heater’s features. For example, a porcelain casing provides a greater level of heat insulation and an additional layer of protection against rusting. Some models come with a self-cleaning feature that flushes mineral deposits in the pipes, which prolongs the unit’s life expectancy. Another factor that affects a water heater’s lifespan is the hardness of the water. The higher the mineral content, the shorter the water heater’s lifespan will be because mineral build up decreases the unit’s efficiency. One way to offset the effect of this mineral build up is to regularly flush the water heater system. Higher-end models normally come equipped with a self-flushing feature.

Though an old water heater may seem to be well maintained, a question arises, is the maintenance worth it? Warranties normally don’t include labour costs. So a good rule of thumb to follow is that if the total annual maintenance cost is greater than 10 per cent of the cost of buying a new water heater, it is probably not worth replacing damaged parts like a sacrificial anode. Obvious signs such as a leaky pond under the heater or cold water coming out of the faucets suggest replacement of the unit. Homeowners should carefully consider the age and warranty of the model, and wisely weigh the cost benefit of maintaining an existing heater versus buying a new one.

Norman Aceron Garcia is a registered Professional Engineer and a Certified Property Inspector of Mr. Peg Property Inspections Inc. Please visit for more information on home inspection, building science and home maintenance tips.

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