In the last 10 years I have had two A O Smith electric 50 gallon hot water heaters. Both have ruptured flooding my house. The first one was replaced under warranty, the second one was not. If you have one good luck they are real trouble and I will never have another one in my house.

Don't buy, it wont last but days past the 6 year warranty. I have 2 in my house, and the tanks went bad within weeks and just over 6 years use. Neighbors have had homes longer than my new one, and they have yet to have problems. The only house newer than mine, had the same HWH, and it died before the warranty, but did little good. It is junk.

I purchased my first home last year in Charlotte, NC. The home was built in 1995 and is 2,625 sq. ft. with 3 bedrooms and 2.5 bathrooms. The water heater was #6 on my list of ten major ($1,000 and up) home improvement projects (following a fresh coat of interior paint, a full-scale kitchen remodel, flooring and restaining the deck). I had a 15 year-old A.O. Smith direct vent gas water heater that started leaking last weekend. From my research, Bradford White water heaters have the best overall reputation and Rheem closely follows with a few scathing comments here and there. It's important to not apply a positive or negative halo effect to a company's entire line of product offerings where one is not warranted. I'm reviewing for the specific unit type noted above. I've seen some very poor reviews for A.O. Smith, but the type of unit reviewed is not always noted and neither is the burden on that unit. I'm a single working professional in my late 20s with an extended house guest. Many homes have had A.O. Smith units installed in excess of 10 years without any major issues. Again, mine had a 15 year run. I don't know if it had any issues in the past, but 15 years is a solid service time. Barring any serious issues in the past, I'd say that's fairly reliable. Regarding cost to operate, it was very inefficient even by yesterday's standards. I don't recall the energy rating on it, but I do know the annual cost to run the unit was slotted at the far right (as noted on the sticker/diagram directly on the unit itself). I'm not in the best position to judge the quality of the unit, but I find it ridiculous to hear about the many instances in which leaks occur. Better materials and methods existed 15 years ago to prevent the kind of failure I observed on my unit, though it is not an uncommon issue after the 15-year mark (a previous reviewer had their unit in service for 21 years). My one-year home warranty under First American covered the replacement expense, less a $55 deductible and an additional out-of-pocket expense ($185) to meet code requirements for my county (I was informed this expense would not be required if my home was located in a particular county adjacent to my own). I did not have any say on the replacement unit. I basically got a comparable water heater...not a bona fide upgrade. I was given a NEW 50 gallon State Select gas direct vent water heater. To my understanding, State is a subsidiary of A.O. Smith. For better or worse, I have a new water heater for $245 out-of-pocket. At least the unit failed while my home warranty was in affect. I guess I can drop the water hear replacement from my home improvement list and move the remaining allocated funds over to something else. Even though the "new" water heater is already outdated at installation, it's more than sufficient for my needs and would comfortably support a larger household for several years coming. No bad.

My 21 year old State water heater flooded the downstairs from Monday to Thursday as I mistakenly thought the flood was from the dishwasher. I finally found it was the heater so I shut the water off Thursday night but of course the 40 gallons of water in the tank continued to come out. By the time I got home from work Friday I was in a panic and went with the first contractor I called. Partly because they said AO Smith was the same company that made my State heater I loved so well, partly because it was Friday afternoon and they were talking over time charges as it was the weekend, and partly because I panicked, I couldn't get the flood to stop. I was assured the AO Smith Promax GVR 40 was top of the line, the warranty was excellent, the contractor stood behind it's work, etc. I have nothing against the contractor, they were efficient, polite and extremely courteous. I awoke Saturday morning to no pilot light. It would not light after following the instructions to the letter several times. I called the contractor who walked me through a trick of lighting the pilot and I was in business again. An hour later no pilot light and this time nothing I did lit it. I called the contractor Sunday afternoon out of frustration when the hot water was gone and the pilot wouldn't light and was told my 24 hour emergency assistance was only good Monday through Friday, so no one would be coming out until some time Monday. I googled AO Smith and see this pilot light issue is a common problem, as is the warranty issue of 24 hour emergency assistance. So I am out almost $1,000, I can't get a refund (I asked), and I have no hot water. As soon as I replenish my savings you can bet I will be replacing my piece of junk AO Smith with maybe a Bradford White.
Denise, California

I bought one new in 2004 for a condo. The heater sits in an enclosed utility closet with 3 other water heaters. The space is really confined and prone to be dusty. Shortly after installation (a couple of weeks). There was no hot water! The installers would not help because they said it was the manufacturers problem. The company did deal with the problem. Now, almost 6 years later, I can't remember what they said the problem was, but I think some part was replaced - rather than putting in an entirely new unit. Now for more than a year the pilot keeps going out. And of course the explanations have been that it's because the heater is in a confined spaced with little air flow and full of dust. No - I say it's poor design. It is COMMON for hot water heaters to sit in a place like mine does. In fact, for more than 30 years hot water heaters have been in this space and these problems didn't occur until I got the AO Smith. Don't buy it!!
Editors Note: The flame for the pilot uses a minimal amount of air compared to the main burners. Hopefully the closet where these water heaters are located comply with mechanical code concerning combustion air.

After 3 years I had to have my igniter replaced - I could have had it "cleaned" but it looked brand new and it was under warranty. I don't think that this is "normal" wear and tear on what is supposed to be a heavy duty hot water heater. It's gas - the 75 gallon version that feeds a house with a family of 6 people. There is no way this is over-used or set up in a "dirty" environment. It's in a partially finished basement. So I can only attribute this to poor quality and give it low marks for reliability. I'm sure my review is tempered by the cold shower I took this morning.