Nicolette Forbes

By: Nicolette Forbes on June 29th, 2022

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Will I Get Instant Hot Water with a Tankless Water Heater?

Tankless Water Heaters

Tankless water heaters are becoming the popular choice of water heaters for homeowners for several reasons, and one of them is the speed at which you get hot water in your home. But does this mean instant hot water?

In this article, we will touch on what a tankless water heater is and how it works, the difference between instant hot water and unlimited hot water, and the ways to get instant hot water from your tankless water heater.

Our technicians at Monkey Wrench Plumbing have been trained and certified with some of the top tankless water heater manufacturers since 2007. We have helped and serviced thousands of customers with their hot water needs, and now we want to help you! 


What is a Tankless Water Heater, and How Does It Work?

A tankless water heater is a water heater that heats your water without the bulkiness of a tank.

Unlike a conventional water heater that is storing the water inside the tank, a tankless water heater heats the water instantly as it moves through the heat exchanger and to your fixture without storing the hot water.

Diagram of a heat exchanger in a tankless water heater creating hot water


Diagram of a hot water being made in a conventional water heater

Tankless water heaters are different from conventional water heaters in the way they heat/store water. 

It’s easiest to think of conventional units as a pot of hot water on the stove. It stays on a flame to get hot. Also, like a pot of water, it has to heat all of the water for you to use it. Once you’re out of hot water, the tank needs to bring in more water to heat up.

For a tankless water heater, on the other hand, water passes through a heat exchanger to reach your desired temperature and exits through your fixtures. Because your water goes through a heat exchanger and not into a tank, your tankless water heater will continue to heat water as long as you need to - giving you endless hot water.

Check out this blog to learn more about the differences between tankless and conventional water heaters.


Will I Get Instant Hot Water with a Tankless Water Heater?

Tankless water heaters are all the rage right now because they save space in your home, are high-tech, and can provide an endless supply of hot water. While tankless water heaters can heat water instantly, they do not give you instant hot water on their own.

We understand that this makes no sense because we just said a tankless water heater heats water instantly. Let us explain.

In short, cold water is heated as it moves through the water heater and is hot until you’re finished using it. When you turn off your tap, the flame shuts off, and the water stops flowing, which causes the water that is in your pipes to cool down. 

So even though the tankless water heater heats the water on demand, the next time you use your shower, you’ll need to wait for that hot water to push all the cool water out of your pipes. 


Ways to Get Instant Hot Water With a Tankless Water Heater

Having instant hot water with a tankless water heater is possible, but you must be wondering, “how?” 

To get instant hot water with a tankless water heater you’ll want to consider getting a recirculation pump installed. 

When you turn off a fixture, a recirculation pump pushes any unused hot water back into your tankless water heater. This process allows the water to be reheated so no cold water runs out of your hot water fixtures.

The water in this process warms up as it moves to provide you with endless hot water. Once you turn off your fixtures, the water in your pipes cools down, and then the process starts over again. While some tankless water heaters have built-in recirculation pumps, some do not, so we recommend that you check your tankless unit’s guide to find out if you already have one.

Recirculation pump on a hot water line on a tankless water heater.

To get a recirculation pump to work, you will need somewhere for that trapped water to go. You can provide that path by having a plumber install a return line or a cross-over valve.


Return Line

A return line is a dedicated pipe that returns unused hot water to the tankless water heater in the hot water line. This water comes back into the tankless water heater through the cold waterline by installing a loop at the farthest fixture in your home. Imagine this as turning your plumbing into a large O to create a continuous loop of hot water.

However, if you cannot access your pipes easily or are simply not interested in doing some construction work, you may want to consider a cross-over valve.


Crossover Valve

A crossover valve is a device you can install at your farthest fixture to connect your hot and cold water lines. In short, a crossover valve turns the cold water line into a hot water return line.

While this will give you instant hot water, this now means if you’re looking for cold water, you’ll need to run your water for a bit to let all the hot water out from your pipes.

If you don’t mind waiting a little longer for your cold water, a crossover valve could be a great solution for you.

Diagram showing how a crossover valve on a tankless water heater works 


Instant Hot Water: Is It for You?

While tankless water heaters can heat water instantly, this doesn’t mean you get instant hot water in your fixtures. But instant hot water with your tankless water heater is possible with the help of a recirculation pump. But to have a recirculation pump installed (if your tankless unit does not already have one) you will need either a cross-over valve or a return line. 

Are you interested in getting hot water instantly?

Read the articles below to learn more about instant hot water with a tankless water heater, the key things you need to know (like price, benefits, etc.), and which option is right for you.

Why Don’t I Have Instant Hot Water with My Tankless Water Heater

Two Ways To Get Instant Hot Water with a Tankless Water Heater

When it comes to tankless water heaters, Monkey Wrench Plumbing wants to set you and your home up for success. If you have any other questions regarding tankless water heaters or any of your plumbing needs, you can call us at 310-853-8690, and one of our call center representatives would be happy to help you.