What’s the Best Temperature for Your Water Heater?

For decades people were taught that the best temperature for water heater use was 140ºF, to the point that a majority of water heater manufacturers put their default setting at this temperature. It has recently come to light that the 140ºF setting may, in fact, do more harm than good to not only the water heater itself, but your home’s energy usage as well.

The Case For 140ºF

The primary argument in favor of the 140ºF setting is that it protects your Orlando home against Legionella bacteria. Almost all types of Legionella bacteria thrive in warm water, especially hot water heaters and hot tubs. Though most people who become exposed to the disease never become ill, it does pose a serious health risk to people with suppressed immune systems and those with respiratory problems. The 140ºF water heater setting superheats water to a point where the Legionella bacteria are killed, without the need for chemical treatment.

The Case Against 140ºF

While there are health concerns for people who are at high risk for Legionnaire’s Disease, most Orlando homes would benefit from setting the hot water heater to 120ºF. The reduced temperature helps to eliminate the possibility of scalding, especially for small children, but the reason that the best temperature for water heater operation is 120ºF is the savings you get. First, a lower temperature means less mineral corrosion and buildup in your heater and pipes, extending their life. Second, raising the temperature the extra 20ºF to reach 140 greatly increases energy consumption when filling the tank, to the tune of more than $50 annually. Finally, the higher temperature results in on demand water waste as you try to find a temperature that is comfortable enough to bathe in. These savings are the most noticeable, hundreds of dollars a year in most cases.

Unless you need the higher temperature to operate your dishwasher or for health reasons, your best temperature for water heater operation is 120ºF. Contact Rinaldi’s Energy Solutions to find out more about energy efficient hot water heaters and other ways you can save money on your monthly utilities.

Our goal is to help educate our customers in Orlando, Florida and surrounding areas about energy and home comfort issues (specific to HVAC systems). For more information about water heaters and other HVAC topics, download our free Home Comfort Resource guide.

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