Home Energy Q&A: Lower water heater setting will help save greenbacks

By Ken Sheinkopf

Published: June 7, 2008

Q: We visited an energy fair last weekend at a local mall, and a water heater company had a big sign telling people they could save a lot of money by lowering the setting on their water heater. They said it was simple to do. Would making this change make much of a difference in our energy costs?

A: I get this question on a regular basis, and I like it because the answer is simply that yes, you can save a fair amount of money by doing this, and yes, it really is easy to do.

I'm reminded of the time we visited some friends a few years ago and the water in their bathroom sink was so hot that I thought I had burned my hands. I asked them why they kept their water heater temperature so hot, and they replied that they had never adjusted it, and just figured that they had very hot water where they lived.

I looked at the setting on their water tank and found it was 140 degrees F. Actually, that's the level that most water heater manufacturers set their tanks at when they are sold — but it's also high enough to give someone third-degree burns in a few seconds!

I asked a few plumbers and was surprised to find that there still is some controversy over the need for this high of a setting.

On one hand, some people argue that you need settings this high to kill all the germs and bacteria in the water that can cause a variety of illnesses (some of this concern dates back to the Legionnaire's Disease outbreak in 1976 when many people at an American Legion convention in Philadelphia got pneumonia attributed to this disease).

On the other hand, it appears that water of at least 122 degrees is hot enough to prevent the bacteria that cause this illness, so raising the setting above this probably doesn't make any health-related changes.

Because a setting of around 120 degrees is hot enough for cooking, cleaning and the proper operation of your dishwasher, the 122-degree level seems the best set point for most household needs as well as from the health standpoint. And while just six seconds can scald you at 140 degrees, it would take putting your hands under 120-degree water for about 10 minutes to cause the same damage.

If you've got an electric water heater, turn off the electricity to the water heater, then unscrew the metal inspection plate on its front. You'll probably need to push aside some insulation after you take the cover off so you can see the thermostats (most units have an upper and a lower one). Use a small screwdriver to set each of the thermostats just above the 120-degree mark. Cover them with the insulation, reinstall the cover and turn on the electricity and you're all set.

If you have a gas water heater, you should find a dial at the bottom of the tank that can be adjusted from warm to hot. Try a few different settings until you get one that you like. Use a thermometer under some running water in the sink to measure the actual temperature.

Lowering the setting to about 122 degrees will still give you enough hot water for household needs, will cut the dangers of scalding from too-hot water, and will help cut down on your water heating costs, which account for between 15 and 25 percent of the monthly utility bill for the average family.

Ken Sheinkopf is a communications specialist with the American Solar Energy Society ( www.ases.org). Send your energy questions to askken@ases.org.

McClatchy-Tribune Information Services

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