I saw an electric water heater made by A O Smith the other day, the serial number of which defied standard decoding rules for determining manufacturing date. The customer knew that his electric water heater was old, but he didn’t know how old and he had no records. One clue was that there was no sacrificial anode. Further investigation turned up an older coding system used by Smith, and according to this code the electric water heater was built in 1979.
Water heater life expectancy, electric or otherwise, is typically cited by the home inspector as twelve to fifteen years on the average, although in some parts of the country there is failure after eight years and in other parts twenty-five years is not unusual. But this particular electric water heater was thirty-two years old and still working fine. Because it was servicing a church rather than a home, its capacity was fifty gallons, albeit used maybe once or at most twice a week, and that use negligible. The TPR valve appeared to be in good condition and functional. The only attention given the electric water heater in the past decade was to drain it once.
Recommendations
The customer wanted to know what to do. Was their electric water heater still safe? Even though there was no evidence of wear, was its age sufficient to warrant replacement? Whenever I find a water heater (gas, electric, or oil) over eight years old, I recommend in my inspection report to monitor it carefully and to plan for replacement, but I stop short of recommending immediate replacement unless there is obvious danger such as a missing TPR valve. In this case, the customer was inclined not to take any chances, so the main question was the nature of the replacement.
Hot water heaters have changed a lot in thirty-two years, and there are many technological options now. They don’t even have to stay electric, as natural gas comes into the space to fuel the furnaces. Other technologies to consider are heat pump, tank-less, and on-demand.
Electric Water Heater Advantages and Disadvantages
Because there is no burner in electric water heaters, they have an advantage over fuel-based ones in that there is no issue with venting, enough combustion air, or flammable vapors. They also require little maintenance (as the one in question clearly demonstrates) and can be tucked away in a corner. The disadvantage of electric water heaters is that they are the slowest kind to recover, usually resulting in larger tanks to compensate. In our case, infrequent and modest use suggests that slow recovery is not a problem.
Other Technologies
Today, many consumers desire better energy efficiency, and electric heat pump water heaters often fit the bill. They achieve their efficiency by applying the principles of latent heat, and they transfer heat from the surrounding space to the water in the tank. They require this space to have sufficient air volume, which, due to heat removal, cools significantly. They also require better access than the electric water heater and a drain line for generated condensate. This option would work well for the church in that the surrounding space is the furnace room, access is not an issue, and the side effect of a cooler furnace room would be welcome.
The minimal use also means that an “on-demand” electric water heater system might prove satisfactory. This could be implemented as a central unit or localized at each faucet.
Professional Help
For the most part, people tend to take their electric water heater for granted. After all, it is usually out of the way and virtually maintenance free. But neglect can lead to problems, ranging from leaks due to corrosion to an exploding tank. It is best to get all appliances serviced and/or a home inspection periodically.
