The average life expectancy of a water heater is about 8 to 15 years. This average will vary depending on how much of a workout your water heater operates under.
Water heating is typically the third largest energy expense in your home. Heating your water typically accounts for about 14% of your utility bill. An old water heater can operate for years at very low efficiency before it finally fails.
Many homeowners wait until their water heater fails before shopping for a replacement. This is unfortunate because the cost of purchasing and operating a water heater can vary greatly depending on the type and model selected as well as the overall quality of the installation.