Tip 18: Setting the water heater temperature

Question: How to I correctly set the water heater temperature? I believe it should be set around 120 degrees.

Answer: Years ago the recommended hot water temperature was 140°F, but that was only for the dishwasher for proper disinfection and cleaning. Today’s dishwashers pre-heat the water to the proper temperature so this high temperature is no longer needed.

According to the US Department of Energy, a temperature of 120 degrees at the tap is adequate for most household chores with a minimal danger of scalding and maximal energy efficiency. You can measure this by turning on a hot water tap and running the water until you are getting hot water. Fill a glass with this water and put a thermometer into the water to measure the temperature. A cooking thermometer will work for this. If the water is too cool turn the temperature control knob on your water heater one notch hotter. Measure the temperature again after four or more hours. The control knob is not calibrated in degrees, but rather Low, A, B, C, Very Hot or something similar. On my water heater I get 120°F water with a setting of ‘B.’

When the temperature at the tap is 120°F the temperature in the tank will be about 130°F which is enough to prevent bacterial growth. If your water heater is now set to 140°F note that you can save 3% to 5% of the energy consumption for each 10°F you lower the temperature.

If you are expecting a houseful of guests you can increase the capacity of your water heater by turning the temperature up one or two notches. With the water temperature hotter you will mix less hot water with the cold thus assuring everyone a hot shower.

Warning: There is a company distributing flyers in Sun City offering to sealcoat your driveway. Do not, I repeat DO NOT contract with this company or any other to sealcoat your driveway. Your community association takes care of this task every two years at no extra cost to you. You don’t have to do anything but take your car out of the garage the night before your driveway is scheduled to be sealcoated and park it on the street until the surface is dry.

If you have suggestions for future tips or have questions about maintenance around your home submit them to ask.the.woodchucks@gmail.com.

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