Hot Water Tank Temperature Settings

Your hot water tank has a vital role - conveniently supplying your whole home hot water on demand. There is a setting on your tank that controls how hot your water is stored at. Typically, new water heaters come from the factory pre-set to a temperature of 140 degrees fahrenheit. Some hot water professionals will say that is the best temp, while others argue it is best to reduce the setting to 120 degrees fahrenheit.

Let's look at the reasoning for both temperatures.

Set at 120 Degrees
120 degrees fahrenheit is the ideal temperature for a hot water tank according to the American Society of Sanitary Engineering. They state it is best for energy consumption - considering it a suitable temp without having to maintain a higher temp of 140 degrees. It is also a temp that kills most bacteria. They estimate that by reducing energy, this will save you approx $60 a year. Cooler water is less likely to deposit minerals in your pipes and help to keep your water flow unobstructed (especially with hard water). 120 degree water also better prevents scalding - it would take 1-2 minutes at that temperature to case dangerous scalding compared to a few sconds at a temp of 140 degrees.

Set at 140 Degrees
With the risk of dangerous scalding, why would anyone suggest raising the tank settings to 140 degrees fahrenheit? According to the Occupational Safety and Health Administration, they consider this temp safer than the 120 degrees setting. Their main reasoning is because at 140 degrees fahrenheit it will kill a specific strain of bacteria that can survive 120 degree temps - Legionnaires' Disease Bacteria (LDB), which can cause serious pneumonia-like sickness. Risk factors for LDB increase with older water systems with rusty pipes that allows water to stagnate outdoors for long periods of time.

Which Setting is Right for Me?
Most home owners can feel good about setting the tank temps to 120 degrees without risk - a home with toddlers or seniors will likely benefit from the potential risk factors of 140 degrees. However, if you know that your water supply is prone to LDB, or have a system that sources from stagnating water, then 140 degrees would be a better, safer option.

Changing Your Temperature
Once you have decided on a suitable temperature for your lifestyle, you'll need to check and see what it's currently set to, and possibly change it. If the tank was self installed, check the manufacture's manual to locate the settings. If you are uncomfortable, or would rather have a professional check, call for maintenance and a thorough inspection can be done.

At 4 Seasons Heating, Cooling & Electrical we are water heater experts. We supply a number of makes and models that work best with your budget and lifestyle. We also have products manufactured right here in Canada. To ask more about our hot water products, or to schedule a service call just call us at (204) 953-5700 or request service online 24/7.