Water heating accounts for about 18 percent of your utility bills, so reducing the water heater temperature can lead to significant savings. Use this guide to help you determine the best water heater temperature for your situation.
Determining the Right Temperature
The standard temperature for a storage water heater is 140 degrees, but the US Department of Energy recommends lowering it to 120 degrees. This slows mineral buildup, reduces scalding at the tap and saves 4 to 22 percent on your annual water heating costs.
Be aware that setting your water heater lower than 120 degrees increases the risk of legionellae bacteria growth in the tank. Therefore, 120 degrees is as low as you should go on a daily basis. Still, you can lower the water heater temperature temporarily to save energy while you’re out of town for a few days.
Factors that Affect the Best Water Heater Temperature
The ideal temperature setting could be different for you compared to your neighbor. Here are the variables that affect how you should set your water heater:
- Dishwasher features: Most modern dishwashers come with a booster heater to help the appliance work more effectively. However, if you have an older dishwasher, you may need to keep your water heater at 140 degrees to ensure your dishes come clean.
- Health problems: The risk of bacterial growth in your water heater increases the lower you set the temperature. If you have a compromised immune system, you should consider keeping the temperature at 140 degrees.
- Number of people in your home: A higher water heater temperature means you have more hot water to go around. If only one or two people live in your home, 120-degree water should be just fine. However, the extra 20 degrees could be useful if you have a family of six or more.
- Children or older adults in your home: Lowering the temperature to 120 degrees can keep younger or older family members safe from scalding at the tap.
How to Adjust the Water Heater Temperature
If you want to set your water heater to a different temperature, follow these tips to make an accurate adjustment:
- Find the current temperature: Many water heater knobs lack temperature readouts. This means you’ll need to measure the temperature yourself. Run the hot water at full blast and place a thermometer under the stream to find out the current temperature.
- Check and adjust the thermostat dial: Mark the starting temperature on the dial with a marker, and then twist the knob slightly.
- Measure the temperature again: Wait a couple of hours, and then measure the water temperature with a thermometer again. If it still isn’t quite right, adjust the dial and re-measure the hot water until you’re satisfied.
- Mark the knob: Mark the new preferred setting on the temperature knob so you can make future adjustments easily.
Tips to Extend Your Water Heater’s Life
No one likes a cold shower, yet few homeowners make water heater maintenance a priority. By taking the following preventative measures every six months, you can extend your water heater’s life and avoid the need to call an emergency plumber in the middle of the night.
Test the Pressure Relief Valve
This valve is designed to open if the pressure inside the tank gets too high. To test that it’s working properly, place a bucket under the pipe leading to the pressure relief valve, which should be labeled. Lift the valve and let a little water trickle out. Now, let go of the valve; it should snap back into place. If the valve sticks or continues to allow water to escape, replace it.
Warning: The water that drips from the valve could scald you, so don’t let it touch your skin!
Flush the Tank
Sediment collects on the bottom of the water heater, decreasing efficiency and eventually corroding the tank. A mini-flush every six months will help the appliance continue running smoothly.
To begin, flip the circuit breaker at the junction box to cut the power to the water heater. Then, close the cold water inlet valve.
Attach a hose to the drain valve, which is near the bottom of the tank, and run it to a floor drain or outside. Alternately, you can place a bucket directly below the drain valve. Turn the handle (or insert a flat-blade screwdriver into the handle-less stem) to open the valve. Open the pressure relief valve as well to help the tank drain more quickly.
If using a bucket, empty it outside or down the kitchen sink each time it fills up. Continue this process until the water runs clear.
Inspect the Anode Rod
Following the mini-flush, inspect the anode rod before you restore power to the water heater and open the cold water inlet valve. This is a small piece of metal that attracts the corrosive elements inside your water heater, preventing the tank from rusting. As the anode rod corrodes, it leaves your tank vulnerable. Occasionally replacing the rod prevents this.
Unscrew the anode rod, which is located on the top of the water heater tank. If it’s less than one-half inch thick or coated in a layer of calcium, replace it. Remember to wrap plumber’s tape around the threads of the new anode rod to ensure a tight fit.
Set the Temperature and Add Insulation
With the anode rod inspection complete, you can now restore power and open the water inlet valve to refill the tank. Set the temperature to an efficient 120 degrees rather than the standard 140 degrees. You can further promote efficient water heater performance by covering the tank with an insulating water heater jacket. Also, wrap pipe foam around the pipes leading to and from the water heater.