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How Long for a Hot Water Heater to Heat After a Reset?

Fact checked by Stephen Conklin

how long for hot water heater to heat after a reset

You’re not alone in asking this question. Resetting a water heater is a must, especially with a faulty thermostat or a power surge. Unfortunately, resetting it also means a waiting period before you can restart enjoying hot water.

Although there isn’t a one-size-fits-all answer to this question because of several factors, water heaters can heat within 30 to 80 minutes after resetting.

Below, I’ll discuss parameters to help you determine how long for a hot water heater to heat after a reset.

Table of Contents

How Long Is the Waiting Time for an Appliance to Heat the Water After a Reset?

First-time water heater owners always ask me, how long for hot water to come back after resetting it? I always find myself telling them it depends.

You see, no two water heaters can have similar heating times. Even identical models from the same brand will have varying recovery times.

So, how long should you wait for your water heater to heat after a reset?

In general, you can expect to wait anywhere between 30 and 80 minutes for you to enjoy hot showers after resetting the water heater. If you have a tankless system, the waiting period is negligible. You can have hot water within 15 to 20 seconds.

Factors Impacting Water Heater Post-reset Heating Times


As mentioned, various factors can impact a water heater’s heating times after a reset. Understanding these parameters should give you an idea of the waiting period.

1. Water Heater Type

It takes a long time for storage-tank water heaters to heat the water because of the volume of water they need to heat in the tank. Conversely, tankless water heaters heat up almost instantaneously after flipping the reset switch.

For example, you’d wait 30 to 40 minutes for a storage-tank water heater to heat the water in the tank. On the other hand, a tankless unit requires 15 to 20 seconds to reach the ideal temperature.

2. Fuel Type

Gas water heaters heat the water two times as quickly as their electric counterparts. If a gas water heater can heat the water in 30 seconds, you’ll need an hour for an electric version to heat the water.

It’s crucial to understand that gas heaters can reach high temperatures faster than the electronic heating elements.

However, the difference is almost negligible between electric and gas tankless water heaters. After all, these devices work on demand. It makes sure hot water come back after shower within seconds.

3. Size

The greater one is a storage-tank water heater’s capacity, the longer it takes to heat the water. For example, an 80-gallon unit will take about 80 to 120 minutes to reach the desired water temperature. On the other hand, a 20-gallon device can complete the water heating process in 30 minutes or less.

4. Inlet Water Temperature

The difference between inlet water temperature and the desired temperature can also impact heating times.

If you live in cold regions where water temperatures can be in the 30s, raising the water temperature to 140 degrees Fahrenheit will take longer.

It’s easy to imagine how long it would take to reach 140 degrees from 30 to 40 degrees Fahrenheit compared to an inlet water temperature of 60 or 70 degrees. Hence, the colder the water entering the water heater, the longer it takes for the device to heat the water.

5. First-hour Rating

All storage-tank water heaters have a first-hour rating (FHR), reflecting their ability to deliver hot water within the first hour of operation. You can see a water heater’s FHR in gallons. In general, a water heater with a high FHR heats the water faster than a unit with a low FHR.

For example, a water heater with an FHR of 80 gallons heats the water faster than a unit with a 50-gallon FHR.

6. Pipe Diameter

Many people overlook this factor when determining how long they should wait for their water heaters to heat after a reset.

You can look at this parameter as the plumbing equivalent to a storage-tank water heater’s size. The larger the pipe diameter, the greater is the volume of water. We already know that more water moving to the water heater translates to longer wait times.

7. Water Heater Age

Brand-new water heaters heat the water faster and more efficiently than older models. It’s essential to recognize the impact of wear and tear on a water heater’s performance.

Heating elements can degrade over time. Sediments and other particles can also accumulate in the storage-tank water heater, adversely affecting the appliance’s water heating capabilities. Thermostats, pilot lights, and other crucial elements can also undergo substantial wear if not damaged.

Poor or inadequate maintenance can also worsen a water heater’s heating inefficiency.

Average Heating Times of Different Water Heater Types


It’s challenging to identify accurate heating times of water heaters because of the various factors mentioned above. What we can do is to create an average of these water heater types.

1. Gas Storage-tank Water Heaters

Gas-powered water heaters can take between 30 and 40 minutes to heat the water after resetting. As a rule, the higher the gas water heater’s BTU rating, the faster the water heating.

2. Electric Storage-tank Water Heaters

These water heaters heat the water two times slower than a gas unit of the same size. For example, if a 40-gallon gas water heater takes 30 minutes to heat after resetting, it would take 80 minutes for a 40-gallon electric water heater to heat.

3. Tankless Water Heaters

A tankless water heater heats the water almost instantly after resetting. Most products heat the water within 15 seconds. However, it’s not unusual for some water heaters to complete the process five seconds longer.

4. Solar Water Heaters

Solar water heaters connected to deep-cycle batteries can heat the water within 60 to 80 minutes, making it almost identical to electric storage-tank water heaters. However, it can take a few hours to heat the water without a power storage solution and on cloudy days.


How long for a hot water heater to heat after a reset? The answer depends on the water heater type, fuel, first-hour rating, size, age, and maintenance. The inlet water temperature and pipe diameter also impact water heating times.

In general, tankless water heaters are the fastest to heat, requiring a fraction of a minute. Second are gas water heaters, taking 30 to 40 minutes to heat. The slowest to heat is electric and solar water heaters, needing 60 to 80 minutes to reach the ideal temperature.

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