Kaitlyn Schott

By: Kaitlyn Schott on September 28th, 2021

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

Tankless Water Heaters

You finally took the dive and invested in a tankless water heater. The rave reviews about endless hot water made your choice easy. So you called up a plumbing company, and they got your tankless up and running quickly. You turn on your hot water, and a shocking realization hits you. The water isn’t instantly hot!

After a minute, the water gets hot, so you pass it off as a new installation issue. That is until it happens again and again and again. You start to get frustrated and annoyed. Why are you waiting for hot water? Why didn’t your plumber tell you about this?

At Monkey Wrench Plumbing, Heating & Air, we get this question from customers all over Los Angeles. This question is so common because of confusion between plumbers and customers. We’re passionate about educating people about plumbing, so we used our expertise to make this easy-to-understand post.

This article will clear up any hot water assumptions you may have about your tankless water heater. You will know why your tankless water heater doesn’t get instant hot water and where the misinformation usually comes from. We will then provide you with the next steps to take if you want hot water as soon as you turn on your fixtures.


HubSpot Video


What Can a Tankless Water Heater Do?


Tankless water heaters give you the ability to have endless hot water. They turn on when you need them and off when you don’t so you can save money on your gas and electric bills. Tankless water heaters are also:

  • Space savers

  • Attractive

  • Durable

  • Safe

The benefits are simple, so where does the communication breakdown happen?


Misconceptions About Tankless Water Heaters


It’s easy to assume tankless water heaters can do everything. Tankless water heaters are high-tech, so why shouldn’t they? While a tankless can do a lot for your household, they do not give you instant hot water on their own.

Tankless water heaters are different from standard water heaters in the way they heat/store water. It’s easiest to think of standard water heaters 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.

In short, cold water is heated as it moves and is hot until you’re finished using it. When you turn off your tap, the flame shuts off, and the water stops flowing. The water in the pipes cools down, so the next time you want hot water, you need to wait for that cool water to leave your lines.


Inside a tankless water heater from Takagi’s page Why Tankless

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


Misunderstanding Tankless Water Heater Terms


The other reason there’s confusion about what a tankless water heater can do comes down to three terms. These terms are often used interchangeably but mean different things:

“On-Demand” - On-demand hot water means you can get hot water whenever you want it. The burner inside the tank turns on when you need it and off when you don’t.

“Endless” - Endless hot water means getting as much hot water as you could ever want.

“Instant” - Instant hot water means getting hot water as soon as you turn on your faucet.


Can you see how confusing a conversation can get if these terms are misused or misunderstood?


Example A: A plumber can say you get on-demand hot water, which can sound like you can instantly get hot water.

Example B: A plumber can misunderstand the term on-demand when training and tell you tankless water heaters provide instant hot water.

Example C: A plumber can accidentally say on-demand hot water when they mean to say endless.

The opportunities for misinformation are endless!


What Can I Do For Instant Hot Water?


Tankless water heaters don’t give instant hot water, but misconceptions and misinformation cause many people to believe they do. We do have good news for you, though! Instant hot water is not impossible. Find out more in our article How to Get Instant Hot Water with a Tankless Water Heater: 2 Options.

To get set up with instant hot water as soon as possible, or if you have any further questions, call us or book us online today!

Want to find out a way to hire the best plumber so you can avoid misunderstandings in the future? Read our blog Top Qualities to Look For in a Plumber.