I bought the rental that was in my new house from Direct Energy. The house was also a new build, so I used their tank for 3-4 months to test it and make sure it had enough capacity etc. 75 gallons power vented is NOT cheap. Then I called Direct Energy and offered to buy their tank from them... it was already installed and in my house, i thought i could get a bargain.
Unfortunately, they wouldn't sell me that tank at a discounted rate until 12 months had passed, and then the amortized value of the tank would drop. So I had to rent for a total of 12 months before buying, and i'm still ahead, since it has lasted three years now. I think that was the break-even point for me.
Most tanks break down because there is some platinum plate or something that helps prevent corrosion... am I right on this? any plumbers care to chime in? Hopefully i can replace that plate before it cannibalizes the tank. I can tell in my humidifier some of the same process is happening, there is a metal plate that is getting sacrificed inside it.