Trouble with AO Smith, heat pump water heater

[William Swanson]

In March 2024, we got a 50 gallon heat pump water heater made by AO Smith. It worked well for the first year, after which the labor warranty expired. Then it stopped working well, and after many phone calls, they say they have to replace the entire unit which will cost us to pay for labor for people to remove the old one and put the new one in. They did not say what it was, just that parts were under warranty and they would replace the entire thing. Going out on the Internet to look, it seems that many people had compressor problems with the AO Smith heat pump water heater. Any experience by other people here in Bloomington?
Bill Swanson
Sent from my iphone.

[Arvind Gopu]

Hi Bill, 

Sorry to hear about the troubles with your AO Smith h/p water heater. My experience is only with GE and Rheem and thus far thankfully neither gave/has given me problems (~8 years and 1.5 years respectively). I'd wanted to buy an AO Smith unit as I found it to be super quiet compared to other brands but I also recall reading about compressor issues - they are just not as common.

When you say "it stopped working well" what exactly is the symptom/issue? Does the compressor run but not heat the water sufficiently? or does it not run at all and the w/h functions as an electric element w/h? If it's a failed compressor I'd imagine anyone with experience fixing fridges should be able to replace it if AO Smith were to send out the part. 

-a

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[William Swanson]

Hi Arvind,

The problem is that in hybrid mode or in heat pump mode, it would periodically stop heating, and not produce an error on the display. If I turn the circuit breaker off and back on again, this fixes it for a few days and then it stops heating again. It always heats an electric mode, but in hybrid mode it doesn’t call the electric heater when the temperature goes down. First we thought it was a controller board, and that was replaced but the problem returned soon after. A.O. Smith only offers the option of replacing the entire unit, not the compressor.

Bill

Sent from my iphone. 

On Sep 18, 2025, at 9:21 PM, Arvind Gopu <arvin...@gmail.com> wrote:



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[Mike Mullett]

Bill, All -

 

    When my wife and I needed to replace our aging, leaking water heater in 2024, we looked very hard at the AO Smith, the Rheem and the Ruud h/p 50-gal hp water heaters.  Our vendor initially had a preference for the AO Smith but ultimately recommended against any of those replacements because of our particular installation situation in the basement of an historic home.  

 

    While our situation was site-specific, I would say this warning on the web re the AO Smith

hp water heater covers it generally -- installation location and air-flow:

 

I saw a post about hybrid water heaters in here and I just thought I would make my own thread to warn people about the AO Smith hybrid water heaters.

I have 2 of them, one in my 4 car garage and the other in my 6x12ft laundry room. The one in my laundry room randomly started throwing a ECC code which according to the manual means you need to contact AO Smith. I did that and they sent a service tech out from a third party to diagnose my water heater. His diagnosis was the problem is my hybrid water heater is not in a 10x10ft room so it doesn't have the air flow it needs to work right and on top of that, they charged ME $170 for the service call because the problem "wasn't AO Smiths fault". About 2 weeks after that, it started working like normal. I didn't do a thing to it, it just decided to start working again and has been working fine since then (it's been about a month or two now).

If you are looking for a hybrid water heater, DO NOT BUY AO SMITH. I can't speak for any other brands, but I can say the principle behind them is great. They only use 500 watts ish when using the heat pump.

One thing to consider with any hybrid is the location, they need air flow and if you are planning to put them in a non-climate-controlled environment that gets below 55-50 degrees in the winter, you will not be able to run the heat pump because of the cold. It will just run forever without doing much, if it doesn't just freeze up with ice. On the other side of that, the hybrid water heater we have inside is nice for the summertime with the extra cooling, BUT, in the wintertime you still get that extra cooling you don't want so there's a tradeoff between saving power consumption from your water heater at the expense of your HVAC system having to heat more in the winter to offset the cooling from the hybrid water heater.

To recap, DO NOT BUY AO SMITH. Ever. Also, be aware of the unique issues hybrid water heaters can cause in the wintertime.

    Mike

 

Michael A. Mullett

723 Lafayette Avenue

Columbus, IN 47201

Phone: (812) 350-0707

E-Mail: mulle...@aol.com 

 

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[Nan McKinley]

I happen to be in conversation with a professional installer right now about getting a heat pump water heater and they said these are highly unreliable and they replace them all the time under warranty. Maybe the tech isn't quite up to snuff yet. 

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[Arvind Gopu]

What a bummer - I'd guess it's a sensor that is supposed to report back on whether the compressor is heating enough or not that's flawed. 

IMO plumbers tend to charge way more than people in many other professions/trades. A water heater swap if you're willing to drain the old one ought to be less than a few hundred bucks. Back in 2012, a local plumber installed mine (in a garage, granted) for like $240 as it was barely an hour's worth of work. HVAC contractors in general fleece the hell out of home owners.