How Long Does A Water Heater Take To Heat Water?
Your water heater affects many day-to-day activities, such as how many showers your family can take in a row and whether you can do laundry and the dishes simultaneously.
Several factors influence how long it takes for a water heater to heat up, including:
- Tank vs. tankless water heaters
- Water heater size
- Gas vs. electric water heater
- First-hour rating
- Temperature rise
Below, you’ll find a detailed explanation of how each factor impacts your hot water supply.
Key Takeaways:
- Choose the right system for your home. Tank heaters store and reheat water over time, while tankless systems deliver on-demand hot water almost instantly.
- Expect larger tanks to take longer to recover. Bigger tanks hold more water, so they take longer to refill once you use them up, but they hold more, so you can take longer showers.
- Pick gas if you want faster heating. Gas water heaters heat nearly twice as fast as the same-size electric models, making them a great choice when you require speed.
- Pay attention to how long it takes your water heater to deliver usable hot water during peak demand.
- Factor in seasonal temperature changes. Colder incoming water in winter increases the time it takes for the water temperature to rise and extends heating time.
- Upgrade if your current system can’t keep up. If you constantly run out of hot water, you may have an undersized or inefficient water heater.
Tank Vs. Tankless Water Heaters
The type of water heater you have makes a big difference in how long it takes to heat up.
For instance, a tank water heater heats and stores water typically over the course of an hour or two.
On the other hand, a tankless water heater doesn’t have a reservoir of already-heated water to draw from. Instead, cold water enters the water heater and is heated by a gas burner or electric element before flowing to the pipes.
Opting for a tankless water heater means you don’t have to wait long for the water to heat up, as it’s nearly instantaneous. Rather than waiting for hours, it only takes a few seconds for the hot water to start flowing.
Water Heater Size
As a general rule, the larger your tank water heater is, the longer it will take to heat up. Most residential water heater tanks hold anywhere between 20 and 100 gallons. Once the tank is empty, it has to heat up all that water again.
If waiting for hot water frustrates you and your family, it may be time to invest in a larger water heater or tankless unit.
Gas Vs. Electric Water Heater
The fuel source of your water heater can also impact how quickly it heats. Typically, gas water heaters heat nearly twice as quickly as electric ones. The average 80-gallon gas tank heats up in 60 to 70 minutes, while an electric tank the same size takes closer to 2 hours. This is assuming the temperature enters the tank at 62°F. If it’s colder upon intake, it will take longer to heat up.
If you want to improve how quickly your water heats up, you may want to invest in a gas water heater. Alternatively, a tankless water heater will eliminate the hour-long wait entirely.
First-Hour Rating
The first-hour rating (FHR) refers to how many gallons of hot water your water heater will provide within the first hour of use. It’s a measurement of how quickly the water heater heats.
As you use hot water, it leaves the tank and goes to the fixture you’ve turned on. As it flows out, cold water enters the tank to be heated. The incoming water lowers the tank’s overall temperature. The more hot water you use, the more cold water mixes in, and the cooler the temperature becomes.
As the internal temperature of your tank water heater decreases, the heating elements turn on to warm it. You’ll initially get consistently hot water when you turn on the faucet, but it will cool down with time.
A lower FHR translates to fewer gallons of hot, usable water within the first hour of use. If your water takes too long to heat, the FHR could be too low for your needs. In this case, you may need to replace it with a unit that has a higher capacity.
Temperature Rise
How long you wait for hot water to heat up depends on the temperature of the water when it first enters the tank. During winter months, these temperatures drop lower than they do in the summer.
If water is flowing into the tank at 40° and you have it set to 110°, that’s a 70° difference. It will take longer to reach the desired temperature than if the water entered the tank at 60°.