Excellent web site. “The average tank life for an AO Smith water heater seems like it’s about 17 years,” Sign me up please 🙂
We have bought 2 AOSmith residential 40 gallon gas water heaters. The first cost $465 in ’99, the tank leaked just after 6 years. The second cost $870 in ’07, the tank leaked after 9 years. We were told the increase in price was due to new regulation to control the gas flame. After the first one flooded our basement, we bought a battery operated water alarm, which beeps when water hits the floor.
They were professionally installed. We haven’t gotten anything close to 17 years. What steps can we take to get more life out of our water heater?
With two water heaters installed in one house the average lifespan seems to be a little less, this is typically due to increased thermal expansion due to heating 80 or 100 gallons instead of just 50. Another factor that will almost always decrease the lifespan of a water heater as well as increase the chance of a flood is the installation of a water softener.
My first recommendation would be to check your water pressure, check for static pressure as well as a possible increase while the tanks are heating. You can buy a water pressure gauge that screws on to your water heater drain or outside faucet for about $15. Some homes will have a PRV which will reduce the water pressure inside your home to under 80 psi. If possible, check the water pressure supplied from the city before the PRV and then again after the PRV. If your home has a PRV and it’s more than 15 years old, replace the PRV. If your water pressure from the city is below 80 psi you can even remove the PRV all together.
If you want to take it one step further and don’t mind a little maintenance you can install a thermal expansion tank. This is only beneficial if you have a closed system. A closed system is created by a PRV, check valve, water softener, or other filtration system. Basically a closed system doesn’t let water back out of the house. It’s important to understand that expansion tanks don’t usually last more than a few years without being pumped back up. A failed PRV can also cause an expansion tank to fill with water which will accelerate the rate of failure.
Other consideration would be to flush out the tanks every year and to replace the anode rods after 6 years or 3 if you have a softener. In all my experience, this these do not seem to have much of an impact here in Kansas City. In other areas where the water isn’t so great this could be more a factor.