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What Does VAC Mean on a Water Heater? (Vacation Mode)

Fact checked by Stephen Conklin

what does vac mean on a water heater

Modern water heaters have many terms too technical for the average person. One of these baffling terminologies is “VAC.” So, what does VAC mean on a water heater?

Although not all water heaters have this feature, “VAC” refers to the appliance’s “Vacation Mode” program. It allows the system to lower the water heater temperature setting and conserve energy while you’re away.

This description oversimplifies a water heater’s VAC setting. Hence, we encourage you to continue reading to learn the details.

Table of Contents

Understanding VAC in Water Heaters


The best way to appreciate “VAC” in water heaters is to look closer and dig deeper into the term and its underpinnings, including what VAC stand for.

1. Definition and purpose


The term “VAC” in your gas or electric water heater is a revolutionary energy-saving feature. It’s a shortened term from “vacation,” implying that this technology only kicks in when nobody uses the water heater for an extended period.

A water heater vacation mode enables the thermostat to lower the temperature necessary to warm the liquid when nobody’s using it for several days or a few weeks.

When you return from a vacation, the water will still be warm enough to allow the hot water heater to deliver hot water faster than relying on cold water.

You’re not only conserving energy when away for a holiday. The VAC on water heater also lets you enjoy a warm shower without the extended wait compared to if you turn off the water heater.

2. When and why to use VAC on a water heater?


The VAC mode on gas water heater units (or their electric equivalent) allows you to go on a holiday without worrying about energy bills upon your return.

The appliance will still be consuming gas or electricity. But the energy expenditure will be lower than setting the device at full blast.

Going on a trip isn’t the only time you want to set the water heater on vacation mode. You’ll want to activate this feature when you don’t use the appliance for several days.

For example, remodeling or renovating your house might require you to vacate the premises, albeit temporarily, to allow work to proceed without interruptions.

3. Setting and using VAC on a water heater


  1. You’ll find a “VAC” label on the water temperature or thermostat panel. Rotate the temperature setting knob until the arrow or pointer is in the “VAC” position.
    Some water heaters might have a different mechanism (i.e., a dedicated VAC Mode button). You’ll want to read the appliance manual for the specifics.
  2. So, what temperature is vacation mode on water heater? That would be 50 degrees Fahrenheit.

Some water heaters allow you to program the VAC Mode to run for a predetermined number of days. It automatically sends power to the water heater the day before the timer expires.

For example, for a weeklong holiday, the water heater will automatically deactivate the VAC Mode and resume normal operation on the sixth day. This action lets you enjoy readily available hot water upon your return.

What to Do if My Water Heater Doesn’t Have VAC?


Only newer water heater models have a VAC Mode. So, what can you do to conserve energy when away?

  • You can always turn off water heater while on vacation. Sadly, this method doesn’t give you readily available hot water upon your return.
    Wait for the water to heat up, which can take 30 to 70 minutes for gas-powered water heaters (and twice as long for electric versions).
  • Please don’t turn off your water heater in the winter to prevent freezing the pipes. Alternatively, manually setting the appliance thermostat to at least 50ºF should produce the same effects as a VAC Mode.


What does VAC mean on a water heater? The water heater terminology is the contracted form for “vacation.” It implies an energy-saving feature for water heaters, allowing users to go on a holiday without worrying about expensive energy bills on their return.

More importantly, families will enjoy instant hot water after vacation. They won’t need to relight the pilot or adjust the temperature setting. The water heater automatically kicks into action a day before the family returns.

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