I see many topics started asking the old proverbial question, "What water heater is the best?" While I can't answer that question without knowing application, location, demand and even your participation with routine maintenance, I can shed some light on limited warranties.
The following is an example from a real service call and a education on limited warranties. Let say you bought a 50 gal 12 year warranty, as stated on the box, water heater from Home Depot in 2005. In 2012 your heater has a tank leak and must be replaced. Clearly you are out of your one year labor warranty but are within the 12 year tank warranty. So off you go to Home Depot to exchange your heater for a new one.
When you get there you find the clerk looking up in her book for the PRORATE amount for the tank. Yes, I say prorate because Home Depot will not give you full purchase price for the heater that you paid for back in 2005. Today's price for a 50 gal 12 year warranty heater with tax is about $675.00 with the prorate credit amount after 7 years is $200.00 according to Home Depot's schedule. The out of the pocket cost to you would be $475.00 plus installation.
Which brings me to the conclusion is buying a 9 or twelve year warranty worth the nearly $200.00 more in price it demands? I'm not picking on Home Depot, other big box stores are most likely similar and should be checked when purchasing a new water heater. And for those contractor brands a plumber installs I can tell you up front most likely there will be an upgrade charge but you should get full purchase price that you paid for your old heater credited towards the cost of a new heater. Normally that upgrade charge is under $100.00.
/Docs/GE_Water_Heaters_Warranty.pdf-- Ej (1/13/2012)