Should my hot water heater be on AB or C?

Author: Dr. Otilia Mitchell  |  Last update: Tuesday, October 14, 2025

These are usually labeled A, B, C or 1, 2, 3, and the last setting is always “Very Hot.” The A or 1 setting should be around 130 degrees, B or 2 is 140 degrees, C or 3 is 150 degrees and “Very Hot” is always 160 degrees. Again, we never recommend setting the unit above the B or 2 setting to prevent scalding.

What does ABC mean on my hot water heater?

C - 150° F - About 1-1/2 seconds. B - 140° F - Less than 5 seconds. A - 130° F - About 30 seconds. HOT - 120° F - More than 5 minutes. LOW - 80° F - No hazard.

What letter should you set your water heater to?

The best setting for gas water heaters is around 115 to 120 degrees Fahrenheit. Oftentimes, water heaters will have additional options to either lower or increase the temperature of the water inside.

What level should a water heater be on ABC?

The next highest setting is usually either labeled as “Hot” or with a triangle, and this setting should correspond to 120 degrees. From there, you will typically see three higher settings marked either as 1, 2, and 3 or A, B, and C that correspond to 130, 140, and 150 degrees, respectively.

What mode should my water heater be on?

So, what is the best temperature range for your water heater? The EPA recommends 120 degrees because it's hot enough to keep diseases at bay but not hot enough to cause scalding. This setting will also supply enough hot water for most small families and is relatively energy efficient.

Change the temperature on electric hot water heater

Should water heater be set to AB or C?

These are usually labeled A, B, C or 1, 2, 3, and the last setting is always “Very Hot.” The A or 1 setting should be around 130 degrees, B or 2 is 140 degrees, C or 3 is 150 degrees and “Very Hot” is always 160 degrees. Again, we never recommend setting the unit above the B or 2 setting to prevent scalding.

What is the best setting for a hot water heater?

Manufacturers often recommend a hot water heater temperature between 120 to 140°F, and there's a reason for this. The Occupational Safety and Health Administration (OSHA) recommends a recommended hot water temperature of at least 122 degrees to prevent the growth of harmful bacteria.

How hot is B on a hot water heater?

That should be plenty hot enough for most uses in your home. Now, some water heater temperature controls come with settings that read “A-B-C” as opposed to numbers. Generally, A means 120 degrees, B means 130 degrees, and C means 140 degrees. Refer to your water heater's manual to confirm these settings.

What should the temperature control be on a water heater?

Consult your water heater owner's manual for instructions on how to operate the thermostat. You can find a thermostat dial for a gas storage water heater near the bottom of the tank on the gas valve. Electric water heaters, on the other hand, may have thermostats positioned behind screw-on plates or panels.

Should hot water heater be level?

Make sure your water heater is level before you install it

If it's not level, the tank may tilt in the direction of the imbalance.

What should a hot water system be set at?

Hot water needs to be stored above 60°C in hot water systems to prevent bacteria growth (such as Legionella), but a tempering valve ensures that the water comes out of the tap at a lower temperature.

What temperature should hot water be for shower?

According to most dermatologists, the ideal shower temperature is anywhere between 98°F (37°C) and 104°F (40°C)—and no more than 105 °F (41°C). Rinsing under lukewarm water allows you to stay comfortable and maintain your body temperature while reaping all the benefits of both hot and cold showers.

Does turning up the water heater make hot water last longer?

Raising the temperature setting on your water heater ultimately makes your hot water supply last longer. It will ensure everyone gets a hot shower, with plenty leftover to run your dishwasher and washing machine.

What is AB vent water heater?

B-Vent, also known as Type B vent or natural draft vent, is commonly used for venting gas appliances that are designed to use indoor air for combustion. These appliances typically have a draft hood to facilitate the flow of air and exhaust gases.

Is 130 too hot for a water heater?

The maximum Department of Energy recommended water heater temperature setting you should never exceed is 140 degrees Fahrenheit. The lowest recommended setting should never be below 120 degrees Fahrenheit.

How long does it take for a hot water heater to heat up?

Here are some common heat up times for different water heaters, assuming the appliances are new and properly sized for the home: Electric storage tank water heater: 60–80 minutes. Propane storage tank water heater: 30–40 minutes. Propane tankless water heater: 0 minutes.

How should water heater thermostats be set?

It's smart to stay within the range of 120 to 140 degrees Fahrenheit (49 to 60 degrees Celsius). Make an adjustment, test it out and repeat until you settle on the perfect temperature setting for you home and water heater.

Why is my water not getting hot?

A lack of hot water can be caused by a variety of issues. In electric water heaters, a power loss or heating element failure can cause water to no longer heat in the tank. In gas water heaters, a faulty gas connection, a bad pilot light, or a bad burner can cause no water to heat.

How often should I flush my water heater?

Most homeowners should flush their water heaters every 6 months or so, but if you have extremely hard water, you may want to do it more often. Flushing your hot water heater could be necessary as often as every few months depending on the mineral content of your local water supply.

What is AB and C on a water heater?

Here is what temperature each letter stands for: Hot- 120 degrees. A- 130 degrees. B- 140 degrees. C- 150 degrees.

What setting should I put my water heater on?

Water Heater Temperature Recommendations

120 degrees Fahrenheit is the safety recommendation against scalding, but 140° is the common default setting.

What is B on a heat pump?

Honeywell uses an O terminal to energize the valve in cooling and a B terminal to energize the valve in heating. Some manufacturers of heat pumps may use the B terminal to energize in heating, while a vast majority energize the O terminal in cooling.

What is the best mode for water heater?

The perfect temperature to set a water heater

And the default setting of 140 F (60 C) may be going away. Recent installation manuals for major residential water heater manufacturers actually call for a starting temperature of 120 F (49 C).

What temperature should a water heater be set at in the summer?

We recommend always keeping the heater set between 110 and 120 degrees. In the summer, try setting your water heater temperature at the low end of this scale, placing it close to or at 110 degrees. In the winter, lean toward the high end of the range. During this season, 120 is a much more acceptable temperature.

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