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Energy CostsIN CHARLOTTEApril 7, 2022by AndrewWhat’s the Best Temperature to Keep a Water Heater?

What’s the perfect temperature for a water heater? It depends on a few factors. There’s a little leeway for personal preferences, too. If you have a water heater, there are some things to understand and think about. Part of the temperature setting will affect comfort, some your energy bill, some safety, some the functioning of the heater itself.

The biggest concern is not setting it too hot, so hot it could cause a major injury or problem to you or a family member. If the heater and your plumbing get too hot, it could cause damage. Here’s a few questions and some help to consider about your water heater and how you should set it.

What’s the Best Temperature at the Tap or Shower?

We could start at the water heater itself, but maybe, the best way to start is with the temperature you want to have when the water gets to you.
For figuring out your perfect temperature, there are two main things to think about. First, what’s the temperature ranges that’s best for stopping or limiting bacteria in water? Second, how hot can water be before it’s a scalding or burning risk?

Water Temperature and Bacteria

From 140-158 degrees, water will kill about 90% of bacteria in about two minutes.

The hotter water is, the more it will kill bacteria. The temperature of your home’s water is a line of defense in water cleanliness and quality.

Water at 158 degrees or more will kill all bacteria instantly. From 140-158 degrees, water will kill about 90% of bacteria in about two minutes. On the other end, water from 90-108 degrees is a perfect breeding ground for bacteria. Water temperatures from 118-112 won’t kill bacteria, but it will stop any reproduction.

Water Temperatures and Too Hot for Safety

On the other hand, you can’t turn up the water heater to be too hot. Your home shower or sink can’t result in injuries, scalds and burns. Water at about 120 degrees can burn some people with five minutes or more of contact. At 130 degrees that time becomes 30 seconds. At 150 degrees, it can be as short as 1-2 seconds.

What’s a Good Temperature for a Water Heater?

So with those pieces of information, you know a level at which bacteria is controlled but the water isn’t a danger.

Professionals advise setting your water heater at a temperature between 120-140 degrees Fahrenheit. Any temperature higher or lower can be a risk, for different reasons. Turning the temperature up higher can result in burns.

Keeping it cooler can lead to bacterial growth. This might end up being a health risk for you as well as your family, possibly resulting in health problems such as Legionnaires’ disease. This illness is a sort of pneumonia and the microorganisms that cause the disease can grow in a water storage tank in between 77-113 degrees.

Inspect Your Water Heater

If you’re worried your water heater is set wrong, be it too low or too high, you can call a plumbing expert to check it and handle it.

If you’ve adjusted the temperature on the heater, but don’t seem to get a change, there can be issues causing this. You can call a pro to inspect the heater and system. This could be from sediment build-up, calcifying deposits or another problem with the tank or a component. A technician might need to drain the tank to inspect the issue. There might need to be a draining and flushing to remove build-up or deposits.

Energy Concerns

The temperature of a water heater can affect an energy bill and how long a water heater lasts, meaning it can cost or save you money. The U.S. Department of Energy says setting a water heater down to 120 degrees may save you 4-22% on energy.

Some dishwashers do not have a ‘water preheat’ mode that allows users to set the water heater to a lower temperature, but still let the dishwasher operate as it should. If you need this for a dishwasher, you may need to set the hot water at 140 degrees.

Considering Immune Health

We might not think of it too often, but our immune system is meant to defend us from infections.

Immunocompromised people might need extra or different considerations when it comes to bacteria, infections and illnesses. People with immune-system needs might need hotter water.

People who are taking medications which suppress or change their immune systems can’t fight off infections as well. Examples of immunosuppressive medicines may be corticosteroids, monoclonal antibodies, biologics and calcineurin inhibitors. The same may be true for people with lupus, psoriasis, Crohn’s illness, rheumatoid joint inflammation and HIV/AIDS.

People going through organ transplant procedures also have affected body immune systems, making them much more prone to diseases or infections.

The suitable temperature for home hot water in homes with immunocompromised individuals is 140 degrees Fahrenheit. While some microorganisms are heat-resistant, a lot of them are killed in 140-degree water. Legionella bacteria dies at 122 degrees. Unfortunately, some viruses can survive at higher temperatures than 140, but setting the water temperature at 140 degrees is a good measure to take for families with immunocompromised people.


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