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Adjust Electric Water Heater Temperature (Step-by-Step Instructions)

Adjust Electric Water Heater Temperature (Step-by-Step Instructions)

by Kim Fauth (email Kim) | | January 19, 2009 | 24 Comments »

Since I just had to do this for our adoption home inspection, I thought I’d post a step-by-step for anyone else who wants to change your hot water temperature.

Why Adjust Hot Water Temperature?

If you can stand shorter (or cooler) showers, turning down the thermostat on your water heater is a great way to save on your electric bill each month.  Also, according to the EERE, a lower hot water temperature reduces mineral build-up and slows corrosion of your hot water pipes.  That’s not why we did it, though.  We just wanted to make sure our faucet readings were well below the 120-degree upper-limit for an adoption inspection.

Note that setting your water heater temperature too high is dangerous, and can result in scalding.  Setting the temperature too low may reduce your dishwasher or washing machine’s cleaning power if they lack an internal heater.  A temperature between 120F and 125F is ideal for most situations.

Here’s general instructions for how to adjust an electric water heater’s thermostats (there are two, one at the bottom and one at the top).  Consult the owner’s manual that came with your water heater for instructions for your particular model.

Steps to Set Water Heater Temperature

THE TOOLS: You will need a phillips-head and a flat-head screwdriver.

 

 

STEP 1: CUT THE POWER – Before you do anything flip the breaker or pull the fuse to turn off the power supply to your water heater, so you don’t electrocute yourself!

 

STEP 2: LOCATE THE TWO THERMOSTAT COVERS – one at the top and one near the base of the water heater.  (In our picture, the two gray doors)

 

 

 

 

 

STEP 3: REMOVE THE COVERS – using the phillips-head screwdriver.  Save the screws in a safe place, since they’re tiny and easily lost.

 

 

STEP 4: REMOVE THE INSULATION behind each cover door to reveal the thermostat behind it.

 

 

 

 

STEP 5: READ THE EXISTING TEMPERATURE – The white triangle on the rotating dial points to a spot between two labeled temperature levels.

 

 

 

STEP 6: TURN THE DIAL to your desired temperature, using the flat-head screwdriver.

 

 

 

 

STEP 7: REPEAT ON SECOND THERMOSTAT.

STEP 8: REPLACE THE INSULATION.

STEP 9: REPLACE THE COVERS OVER BOTH THERMOSTATS.

STEP 10: FLIP THE BREAKER TO RESTORE POWER TO THE WATER HEATER.

What do you think? What temperature is your water heater set to?  Have you adjusted it to save money?

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24 Responses to Adjust Electric Water Heater Temperature (Step-by-Step Instructions)

  • Todd responds...
    January 19th, 2009 9:44 am

    Great post Kim. This method works for direct fired water heaters. If you live in a house with indirect water heaters you’ll need to adjust mixing valve from the boiler to the tank.

    Another note, some building codes require hot water to be a minimum of 124F at the faucet and 140F in the tank to prevent Legionnaires Disease.

    [Reply]

  • Kim responds...
    January 19th, 2009 9:53 am

    … and that’s why we have you! Thanks for adding that in, Todd!

    [Reply]

  • Todd responds...
    January 19th, 2009 11:27 am

    Not a problem….the interesting thing is today most people are told to put their water to 120 F yet building code officials frown on it. It never fails that there are two camps out there offering us “safety” rules that never seem to align.

    [Reply]

  • Jon McDougal responds...
    January 19th, 2009 1:03 pm

    Shouldn’t you have a nice thermal wrap around that, to help conserve the heat and save on your power bill?

    It doesn’t get cold enough to do that down here.

    -Jon

    [Reply]

  • Kim responds...
    January 19th, 2009 4:02 pm

    Yes, we’ve been meaning to get a wrap. The water heater was new this past April and we just haven’t gotten to it. But it’s plenty cold enough here! (snowing as I type)

    [Reply]

  • Ethan responds...
    January 19th, 2009 4:31 pm

    Often newer water heaters don’t really benefit too much from a thermal wrap as they are so well insulated. I’d guess that wrapping your hot water heater won’t really save too much Kim. Typically, if the water heater is warm to the touch, you can benefit from a blanket.

    [Reply]

  • Reeves responds...
    January 20th, 2009 3:15 pm

    Should both of the thermostats be set to the same temperature or should the lower one be set to a lower temperature because of tank stratification?

    [Reply]

  • Fred responds...
    January 23rd, 2009 1:03 am

    Reeves, The thermostats should be set to the same temperature to avoid one element burning out before the other. Setting the thermostats the same avoids one element “overworking”

    [Reply]

    Arthur Sgambelluri Reply:

    The lower element works more than the top just because cold water refil enters at the bottom. Warmer water migrates to the top and requires less heat to raise temperature….stratification…

    [Reply]

  • Booster responds...
    May 19th, 2009 8:59 pm

    Would if I didn’t care about one element going out before the other? Would it save money to set one higher than the other? Which one?

    [Reply]

  • Kim responds...
    May 21st, 2009 12:41 pm

    I’m fairly sure you wouldn’t save energy, since the one element would have to work harder to make up the difference of the other one being set lower. The best way to save cost is to set them BOTH lower and to take shorter showers (getting done before the water runs cold!).

    [Reply]

  • ish responds...
    November 19th, 2009 11:19 am

    we took a cold shower this morning at our new house, i was scratching my head wondering what the heck was wrong with the water heater! but thanks to this post my life just got brighter, thanks!!

    [Reply]

  • Rhett Frady responds...
    January 11th, 2010 12:21 pm

    Have a rental house. Young lady said water was not real hot and she ran out quickly. Lives by herself so not a lot of water used from the 50 gal tank. I suspected one of the elements and opted to replace both as the heater is just over 4 years oll.. Replaced both, water is much hotter, however, she still runs out. I put two of the 2 pronged elements in. Originally, it had a single and a double installed. Did not mess with temperature settings, which are at 126. Any ideas

    [Reply]

    Ted Reply:

    I have a tankless heater on my oil fueled boiler. The water is not that hot, and does not stay hot for that long. What temps should I keep them on. The low is on 140, and the high 180

    [Reply]

  • alex responds...
    February 4th, 2010 12:46 am

    great post, it helped a lot, thanks!

    [Reply]

  • Ingrid responds...
    February 23rd, 2010 2:46 pm

    This has been a GREAT help. We’ve wanted to do this for months and just have’nt known how.

    Question: Is there only one thermostat on a 32 gallon water heater? I removed both cover plates and the top one had only wires behind it.

    [Reply]

  • Kim responds...
    February 24th, 2010 12:20 am

    Hi Ingrid,
    Yes, it’s entirely possible that your 32-gal only needs one thermostat. Ours is a 50-gal., so it has two. You can check your instruction manual (or search online; most manufacturers have .pdf’s you can download for all their models) just to verify if you’ want to be absolutely sure.

    But I didn’t have to go digging around for ours; they were right there behind each door, so I’m betting yours only needs one.

    -Kim

    [Reply]

  • Adjust Gas Water Heater Temperature on One Project Closer responds...
    November 30th, 2010 7:02 am

    [...] For some time, one of the items on my to-do list was to adjust our water temperature. This project quickly climbed my  list as colder temperatures have arrived. Fortunately, it’s a 5 minute job. Here’s a step-by-step guide for adjusting the temperature on a gas water heater. If you have an electric heater, Kim wrote an excellent post detailing how to adjust electric water heater temperatures. [...]

  • YBR responds...
    December 9th, 2010 12:24 am

    Thanks! Not only is this a good guide….that’s my new water heater in the picture!

    [Reply]

  • Frank Jones responds...
    December 27th, 2010 2:27 pm

    How do you know that both thermostats on an electric water heater are set to the same temperature? The numbers on the dial have no relationship to the actual temperature at which they operate(example: my new heater came set at 125 degrees, but the water at the closest faucet–about 6 feet away–was in the 90 degree range.)
    I raised the temperature settings an equal amount on both thermostats until I got 130 degrees at the faucet. BUT, I notice that in the shower, the temperature starts off at about 130, but then drops noticably after a few minutes; it doesn’t get cold, just a few degrees cooler. It doesn’t run out of hot water during any reasonable shower
    I suspect that there is a small “pool” of warmer water at the top that is used up first, then the cooler layer starts through.
    So, is my upper setting actually higher than my lower setting? How can I tell if the two elements are actually coming on, and turning off, at the same time?

    …thanks

    [Reply]

    Art Reply:

    Great diagnosis…you’re likely correct. Some upper tstats are known as double throw which do not allow both to be on at the same time, AO Smith. When you raise the temperature of the upper thermostat the lower thermostat will deenergize regardless of the lower set point.

    [Reply]

  • John Wilson responds...
    January 21st, 2011 12:24 pm

    We just had a new water heater installed after the old one burst. I asked the plumber if I needed a thermal blanket, he said no, the newer units had plenty of insulation and that wrapping them trapped more moisture around the unit causing it to rust prematurely.

    [Reply]

  • Paul&Aundrea responds...
    January 9th, 2012 5:27 pm

    I’m going to look into a thermal blanket. We live in my grandmother’s old house, and who knows how old the water heater is. It is just my husband and I and if we both shower back to back the 2nd one always runs out of hot water. This usually isn’t a problem since I like to shower at night and he showers in the morning. I didn’t even think to look at what temp. it is set at.

    [Reply]

    Kim Reply:

    You shouldn’t have to stagger your showers like that (unless you’re taking mighty long ones!).

    [Reply]





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