I had to replace my electric hot water tank recently and few months later have been noticing that this new one is not supplying a good amount of hot water vs. my old one. They are both the same size.

When 3 people have had a shower during the afternoon/night then the 4th person goes to shower they will notice the water is cold and no hot water. This never used to happen with my old tank. What could be wrong with this new tank? How can I find out the issue? Is there something I can do to fix?


  • 3
    Could be one of two reasons. #1 the installation was not quite right. #2 the thermostat is turned down for safety. Most new tanks are only set at ~120F to prevent skin burns, the old tank might have been higher, so you added more cold water to your showers.
    – crip659
    Jul 13, 2022 at 11:15
  • 1
    @crip659 - this would be better as an answer rather than a comment.
    – Tim
    Jul 13, 2022 at 11:57
  • 1
    Should have said three reasons. #3 is it possible that the first three are just taking longer showers?
    – crip659
    Jul 13, 2022 at 12:27
  • 2
    Isn't there also a "recovery rate" statistic for water heaters that determines how fast they can make hot water?
    – izzy
    Jul 13, 2022 at 12:38
  • 1
    Model number of the new heater? Jul 13, 2022 at 13:10

1 Answer 1


That 4th person is going just have to wait for half an hour for the WH to recover! Or get the previous shower users to take shorter showers!

But seriously, a few things come to mind: like crip659 said the thermostat might be set too low or the new WH has a defect. Maybe one of the elements isn't working or one the thermostats. That's about all that can go wrong.

Electric WHs are pretty simple: Usually 2 elements controlled by a couple of thermostats. First the lower element comes on as needed since that's where the cold water comes in. Then, if a lot of hot water is used and the upper part of the tank gets cool, the upper tstat turns off the lower element and turns on the upper one (both can't be run at the same time, too much power needed). Next thought: What was the wattage of the elements on your old WH and what's the wattage on the new one? Hopefully 4,500 watts. If less on your new one, it obviously won't generate the same amount of HW.

Next: There's a way to "increase the capacity" of your new WH. Well, it doesn't really increase the physical capacity, obviously, but you can do it virtually with a mixing valve installed on the WH. Then you crank up the tstat a lot, like to 140 or 150, but to keep everybody safe, the mixing valve tempers the outflow with cold water to the desired temp (usually 120). This works because you'll be using less HW to supply the house.

Since I'm "working from home", LOL Here's your to do list:

  • Check the thermostat settings, if too low you can turn them up a bit, but be careful you really want to avoid scalding.
  • Ensure both tstats and elements are working correctly
  • Check the wattage of the elements on your new WH
  • If you're still not satisfied with the HW production, think about the mixing valve approach
  • Hooking up a 240 Volt HWH to a 120 Volt supply is another way to lose out on hot showers...
    – DJohnM
    Jul 15, 2022 at 4:25
  • @DJohnM that's certainly true, but since he replaced an existing WH with one of the same size, it's easy to assume the old one was 240v. But it never hurts to double check. To the OP, can you describe the breaker servicing the WH? is it double wide and what is it's amperage rating. Jul 15, 2022 at 5:47

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.