I have a new water heater with an 8 year warranty and I noticed that the warranty length is included in the model number.

On the manufacturer's website I couldn't find any information about differences in the fabrication process of a water heater with an 8 year warranty and one with a 4 year warranty (for instance, a thicker layer of glass or a bigger anode rod).

My question is, did I buy an "entry level" water heater with a hidden extended warranty or is it really built better?

  • 3
    No warranty is, for any product, ever. They're all sales strategies based on complex financial calculations and human behavior predictions.
    – isherwood
    Commented Mar 9, 2016 at 17:44
  • The difference between most appliances is the labels and paint (even across brands). I doubt there are two separate manufacturing processes which would improve build quality. It's possible that some units score higher on tests which indicate they will last longer and therefore get a longer warranty they can use to up-charge. In which case, the build quality may actually be better. This is all speculation of course--an actual answer would have to come from an industry insider. Commented Mar 9, 2016 at 18:11

1 Answer 1


For water heaters, the warranty duration is an indication of approximately how long the included anode rod will last before it needs to be replaced to preserve its protective qualities. Since almost nobody replaces their water heater's anode rod, the number of years listed on the warranty can actually be taken to show about how long the unit will last. For example, a 6-year-warranty unit will probably have a warn-out anode rod in 6 years, so by year 7 or 8 it might leak if not replaced.

Longer warranties on glass-and-anode-rod units usually point to more and better anode rods. One aluminum rod would be the minimum (4-year warranty) while two magnesium rods would probably be the best (12 year warranty).

This implies that you can make your water heater last much longer than the warranty duration simply by replacing the anode rod(s) every such-and-such number of years, and this implication would be correct.

Or you can buy a unit with a stainless steel or plastic interior tank and no anode rod at all, most of which have a lifetime warranty. They're not much more expensive than the glass-lined tanks with aluminum or magnesium anode rods. The HTP/Westinhouse Everlast and Rheem Marathon are two such products.

  • 2
    Thanks for you answer. This is probably the way it works for most manufacturers but I contacted my WH manufacturer and they told me that the warranty for my model is 6 year in the US and 8 year in Canada. Maybe water is less corrosive in Canada...
    – ForguesR
    Commented Mar 10, 2016 at 14:00

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