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tankless water heater

Do Tankless Water Heaters Run Out of Hot Water?

If you have a tankless water heater or are thinking about getting one installed, you may have asked yourself: Do tankless water heaters run out of hot water? We’ll answer this question shortly.

Most people love taking a warm bath or shower. It’s comfortable, enjoyable, and a welcoming feeling after a hard day’s work. If you have a tankless water heater, it helps to have consistently warm water.

Having a never-ending hot water heater is possible. American Home Water & Air can help make that happen so that you have a hot water heater that never runs out.

However, let’s answer that million-dollar question first and foremost: Do tankless water heaters run out of hot water?

No, tankless water heaters can never run out of hot water. This is because, unlike tanks, tankless water heaters do not store water. 

How Does A Tankless Water Heater Actually Work?

You’re probably asking yourself: how do these tankless water heaters actually work? Let’s explain the useful elements that make it all happen so every shower you take at home is always warm from start to finish.


Thankfully, there is a technological advancement that can allow for endless hot water. You read correctly. If you have suffered through a lukewarm or cold shower, you know the pain of a shower that ends too quickly. There is a solution: a tankless water heater. A tankless water system heats water via gas or electricity, just like a heating system with a water tank. 

The difference is that the former intakes water and heats as needed, whereas the latter stores water at all times. A tankless heating system may be exactly what you need. Keep reading to see the benefits a tankless heating system can provide, including unlimited hot water.

Inner Workings

To understand a water heater, you must first understand the inner workings of a heating system. Most hot water systems feature a water heater storage unit. Water heater tanks are especially prevalent in apartment buildings and other shared home arrangements. Because of these heating systems, people must divide up shower time accordingly. A storage tank holds water for times when hot water is necessary. 

A tank comes in a predetermined size. A tank can fit in a basement or even a closet. This tank of water is kept warm by either natural gas or electricity. When the water tank runs out, it refills and takes time to reheat. Because the tank does not store unlimited water, there are times where there is no hot water in the tank. As a result, the hot water runs out fast, and the home does not have access to hot water. 

A tankless water heater does not store water. Therefore, a tankless water heater does not run out of hot water. The preference between a tankless water heater and a water system with a tank is up to you to decide.

You Don’t Need To Wait Any Longer For Hot Water

The days of waiting for the water to warm up are over. Even better, you don’t have to worry about running out of oil and letting the water go cold in the process.

Without a storage tank, you will have no worries about depleting a finite amount of water that you reserve in your home.

Even better, they are easy to maintain. So if it appears to be not working, you might have a good idea of what to do. 

There are limitations to a tankless water system, however. A tankless water system has a supply that dictates how much water can heat per minute. The amount of water heated per minute is measured in gallons and varies depending on the heating source—gas or electricity. 

Gallons Per Minute

The average tankless water system supplies 2-5 gallons of hot water per minute. Blasting all faucets simultaneously would cause a problem because of the 2-5 gallon per minute limitation. Work with your water specialist to determine how much your tankless water heater will supply. Another consideration regarding your water system is whether it uses gas or electricity. Much like a water heating system with a tank, a tankless system gets fuel from electricity or gas. 

Gas and electricity have different heating mechanisms and allow varying gallons per minute. The gallons per minute, or GPM, dictates the flow rate of hot water into the home. Determining specificities will ensure the best possible water heating experience.

Do tankless water heaters run out of water? Hypothetically, tankless water heaters do not run out of water, as long as there is a water supply. Of course, a tankless water heater can be overwhelmed. When a tankless water system is overwhelmed, the demand is too high.

An example of the potential for overwhelming the hot water system would be running five showers at once. Multiple simultaneous showers are normal in high-traffic areas like gyms or hotels. In a home, the water specialist evaluates the water supply and demand. After effectively calculating the supply and demand of your home, a water specialist will install heating water services on your home. 


Do tankless water heaters run out of water? To repeat, they don’t. Now that you know the answer, you can make an informed decision as to whether a tankless water heater installation is right for you. 

American Home Water & Air is your Arizona plumbing service that will supply you with unlimited warm water—no more waiting for the water to warm up or relying on other factors. Now that’s a wonderful thing to have.

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