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How To Adjust the Temperature on Your Water Heater

Warning for anyone changing their water heater temperature!
Scalding is very serious and adjusting your water temperature higher can increase the likelihood of scalding. If you are at all unsure about your ability to complete this project safely, please consult with your plumber prior to beginning. Additionally, please be aware that children, the elderly, and those with compromised skin integrity can be scalded in water as cool as 110°F.

Check the Current Temperature First

Whether you find your hot water is coming out too hot or not hot enough, knowing how to adjust your water heater can be very beneficial. Before changing the current settings, it's a good idea to check the temperature of your hot water at the tap so you will know how much to adjust the heater. Just about any standard cooking thermometer will work just fine for this.

To calibrate your thermometer, hold it in a cup of ice water, until the temp. dial goes down to 32 degrees (or stops at the lowest degree on the gage). This basically resets the thermometer so you will get an accurate temperature reading.

While the thermometer is calibrating, run the hot water from a faucet closest to the heater, until its hot to the touch (but don't burn yourself!). Then fill a cup with hot water and place your thermometer in the cup of hot water.

The temperature dial will stop on the temperature of the water. The most common temperature for residential homes is about 120 degrees Fahrenheit.

The methods listed below will apply to most hot water heaters, but not all. Each water heater manufacturer may design their unit differently, but most will function the same.

Electric - Tank Water Heaters

Most electric water heaters will have two thermostats, one upper and one lower, under the two control panels. For your water heater to work most effectively and efficiently, the two thermostats must be set at the same temperature. Some smaller units may only have one thermostat.

Tools needed:

  • Philips-head or flat-head screwdriver

Step 1:
Turn off the power to the heater. This will usually mean finding your circuit breaker and turning off the power to the general area.

Step 2:
Locate the thermostats, most will be concealed under an access panel. Open the access panels, these usually attach with four screws. Use the appropriate screwdriver to remove them, place them in a safe place to prevent losing them.

Step 3:
Most electric water heaters will have two thermostats, one upper and one lower, under the two control panels. Some smaller units may only have one thermostat. If your heater has been insulated, you may need to remove the insulation to access the thermostat. The thermostats will have a dial, and these dials can read differently depending on the manufacturer of the heater.

Step 4:
Although the dials may read differently, all will indicate hotter in one direction or cooler in the other. Depending on what your needs are and why you are adjusting the heater, adjust the dials slightly with your screwdriver. Be sure to adjust both of the thermostats the same amount.

Step 5:
Close the panels and reattach the screws.

Step 6:
Restore the power to the heater.

Step 7:
Wait about 3-4 hours and re-test your hot water temperature. If the temperature is still not satisfactory, follow these steps again until it is just right.

Gas - Tank Water Heaters

Most gas water heaters will have a simple, easy to read dial at the bottom of the tank. (Some models will have a concealed dial under an access panel; if this is the case, use the steps above to adjust them.)

Tools needed:

  • None!

Step 1:
Turn the knob warmer or cooler, depending on your needs.

Step 2:
Wait about 3-4 hours and re-test your hot water temperature. If the temperature is still not satisfactory, follow these steps again until it is just right.

Tips:

  • Lowering the temperature on your heater will save you money on your energy bill.
  • If you're going on vacation lower the temperature on your water heater to the lowest setting to save energy and money while you're gone.
  • Most manufacturers recommend a temperature setting of 120 degrees.
  • Typically, most households with children will want a temperature slightly below 120 degrees to prevent any chance of scalding. Some adults prefer hotter water and may be comfortable with a slightly higher setting.
  • Some household appliances (like dishwashers) require higher temperatures of about 140 degrees to properly kill bacteria; however, since most modern dishwashers pre-heat the water, lowering the temperature should not affect the dishwasher.


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Please note: This 'how to' is for tank-style water heaters and does not apply to tankless water heaters.


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