What Temperature Should a Water Heater Be Set?

Your water heater accounts for approximately 18% of your home’s energy bill. If your water heater is set too high, your energy bill will be unnecessarily high each month. On the reverse side, if your water heater is set too low your water may not get hot enough causing short showers, or worse, being at risk of growing bacteria.  If you have a water heater with a tank, you are paying to keep the water in the tank hot around the clock. Even at 3 a.m., when everyone in the house is fast asleep, your water heater is warming the water for your use. You can save a little energy and money by decreasing the water heater’s burden. 

Don’t set your water heater to anything below 120 degrees, as diseases, particularly Legionnaires' Disease, can develop in the stagnant water inside the water heater, which is quite dangerous.

What is the best temperature range for your water heater? The EPA recommends 120 degrees for several reasons

1)  It’s hot enough to keep diseases at bay

2)  It’s not too hot to cause scalding burns

3)  It will supply enough hot water for most small families and is relatively energy-efficient.

• However, the best setting for you could vary based on a few factors.

Factors That Affect Hot Water Temperature Setting

These factors are not affected by the kind of plumbing you have (PEX, PVC or copper), how the water is heated (gas or electric) or even if you a tankless water heater.

• Homeowners with a dishwasher that does not pre-heat the water may want to set their water heater to 140 degrees.
• Elderly homeowners or those with small children may want to keep the temperature at 120 degrees. Elevated water temperatures can quickly burn children.
• Homes with occupants who have a suppressed immune system or respiratory disease should keep the hot water set to 140 degrees.
• In general, for those who live alone, aim for a lower temperature in the acceptable range since the demand for hot water is less and it saves money.
• For those who live in a large household, aim for a higher temperature to accommodate the increased demand for hot water.
• If you want to save money, for every 10 degrees you turn down the water tank thermometer, you can save 3 to 5 percent on your energy bill.

Still undecided? Set it at 120 degrees and increase the temperature in small increments until you find the perfect shower temperature.