Could you please help me answer the following questions?

1) Will unplugging my water heater from the socket when not in use damage it?

2) Which energy-saving timer will work with my water heater?

Below are details of my water heater.

Company: Rheemglas Standard (Energy Miser)

Water Heater Model #: 0199B54937

Wattage: 240/208 Volts AC ONLY

Upper: 4500/3380

Lower: 4500/3380

Total: 4500/3380

Already Tried: I have already tried contacting Rheem customer support; however, no one has responded to my inquiry yet.

Listed UL Water Heater 786H


Temporary picture gallery showing (1) electric water heater plug, (2) air conditioner's stand-alone switch, and (3) air conditioner unit above electric water heater.

Pics added inline enter image description here

enter image description here

  • 1
    It will not hurt your water heater but you may be shooting your self in the foot because once the water cools off it will be a long recovery time. If you only use hot water once a day it may be worth it to have the heater come on an hour before you need it then turn off at the time you would be gone.
    – Ed Beal
    Oct 11, 2016 at 19:09
  • Ed Beal - I use hot water only once a day. So if I were to unplug the water heater from the socket, would I need to do anything else (e.g., drain/flush the water, move pressure valves/handles)? Oct 11, 2016 at 19:48
  • 1
    You would not need to do anything else. Is there a temp control knob that might be safer than unplugging a high amperage plug daily although circuit breakers are not rated to be switches turning the breaker off would be a better idea than unplugging. I have not had time to look up the model the elements both rated at 4500 W with the total of 4500W sounds like 120V elements but that would be unusual water heaters are not required to have a neutral and no neutral calculation / reduction is allowed I will try and figure out what time of timer will work later this evening.
    – Ed Beal
    Oct 11, 2016 at 21:32
  • I appreciate your help. Similar to my central air conditioner, my electric water heater isn't in the breaker box. It simply has an outlet on the side to plug the water heater into. My AC, for example, has a stand-alone switch near the heating and cooling equipment, and the builder put it right above the water heater. Please visit the temporary picture gallery to view images of my electric-water-heater-and-air-conditioner setup: unsee.cc/mugobide. Oct 11, 2016 at 22:26
  • 1
    @EdBeal -- they are 240V elements, but are never on at the same time. Oct 11, 2016 at 23:26

2 Answers 2


I would suggest a timer like this. Additional start/stop pins can be added if you decide on adding a second on off time (or more) and you can always flip the over ride to the On position. This way your water will be hot in the morning instead of having to wait after you turn it back on.

The only problem is if there is a power outage you would need to adjust the clock face (very easy). I would suggest an absolute minimum rating of 30 amps. This model is rated at 40 and I have had excellent long term service with this brand and style.

  • 1
    The message is: the IKEA socket timer is not rated for this!
    – yo'
    Oct 12, 2016 at 15:30
  • My electric water heater isn't located in the breaker box, so would I still be able to use this timer? I prefer a solution where I can simply plug the timer into the socket. Oct 12, 2016 at 16:02
  • By the way, even though Harper points out that I shouldn't unplug and plug the outlet on a daily basis (since it's not rated for frequent use [and I won't touch it anymore knowing that now]), could you please tell me whether it'd cost more to leave the electric water heater off when not in use? Or would it save more money to keep it on 24/7? Oct 12, 2016 at 16:12
  • Harper clarified that it costs more to shut off the water heater and turn it back on. Yo' - I don't understand your comment. Could you please clarify what you mean by "the IKEA socket timer is not rated for this"? Oct 12, 2016 at 17:25
  • Correction: ** ...it does NOT cost more to shut off the water heater and turn it back on. Oct 12, 2016 at 17:26

Do not plug and unplug that outlet on a daily basis. That is probably a 30A rated receptacle (probably NEMA 6-30 or 14-30) and those are not rated for frequent use. (Most especially the obsolete NEMA 10-30 -- it would be illegal except for the rationale that it is rarely unplugged and is therefore unlikely to fail deadly.)

I'm unclear on what the box is, in your second photo. I don't see an operating handle but it's the right size to be an ultra-heavy grade switch. If it controls only the water heater, you can use that to turn it on/off.

A timer would be fine. We're not a shop-for-you site so I don't recommend any particular product.

In our similar installation, we added a plain switch. (heavy-duty of course). I have my eye on a "twist" timer switch like you see on bathroom heat lamps. They can be had in times 0-5 minutes clear up to 0-12 hours -- and with or without an "always on" detent.

enter image description here

You could even use a "smart switch" and command the heater to turn on with your phone.

Or the cheap option is to change the circuit breaker to one that is listed for daily use as a switch. Some breakers are.

Anything you use must be rated for the amperage of the receptacle, wire and breaker, for instance you are not allowed to use 20A-rated gear on a 30A receptacle. Also the device must be UL-listed (or whatever your region's listing authority is) - and it must have a proper enclosure, no dangling devices or exposed terminals. And be properly mounted.

You may run into a problem where you love a switch/timer, but it cannot support 30 amps. Don't use it directly: use a relay do the heavy switching. This is getting a little more complicated, but not terribly so. The relay must be rated for 30A, but the devices controlling the relay do not.

  • The second photo is an image of the AC's stand-alone switch. I added it to give posters a better idea of my unique situation. The third photo (had it been added) shows my AC unit above the electric water heater. So, in my opinion, the heater is constantly trying to keep the water hot as the ac pulls in cool air through the grill. This results in high electric bills. Nonetheless, neither my AC nor the electric water heater is located in the breaker box. I don't know whether I'd be able to change the circuit breaker as you suggested. I am very interested in your smart switch option, though! Oct 12, 2016 at 15:58
  • Does it really cost more for the electric water to heat up the tank instead of maintaining it 24/7? Oct 12, 2016 at 16:01
  • @TechEnthusiast The water heater should be well insulated from air around it, under that metal should be several inches of foam insulation. Poor insulation will reduce efficiency. Efficiency can be enhanced by adding an insulating jacket around the heater, home improvement stores sell those. That is where all your losses are, because other than that, water heaters are literally 100% efficient as there is nowhere else for the heat to go, except into the water. Oct 12, 2016 at 16:23
  • 1
    NO, that's an old wives tale spread by lazy people who want the convenience of it already being on. It's always cheaper energywise to turn the thing off. The ONLY valid reasons are non-energy-related, and only apply to certain things, typically where startup/shutdown adds wear-and-tear, and the maintenance costs are so high that it justifies the energy waste -- like a nuclear reactor. Or metal-halide bulbs are good for about 8000 starts, and that may matter in a warehouse if you don't own a boom-lift and have to hire one in. Oct 12, 2016 at 16:31
  • Thank you for shedding light on that outdated traditional belief. Sounds as if adding both an insulation jacket and a timer will help lower my monthly bill significantly. My water heater has an R-value of 11.5, so I may buy a non-fiberglass insulation blanket like this one: Duck Brand Water Heater Insulation Blanket (R-value 9) on either Amazon or Walmart. My only problem now is finding a simple plug-in "smart switch" that doesn't require meddling with the breaker box (since it turns out the heater is actually connected to the power for the entire hallway). Oct 12, 2016 at 16:39

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