Why does it take so long to get hot water from my tankless water heater?

Beginner Info, Tankless Water Heater

why does it take so long to get hot water from my tankless water heater
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Well, to be honest, as compared to a conventional water heater, a tankless water heater does take a little bit more time.

But, it has nothing to do with either the quality of a tankless water heater or its efficiency rather it has to do with the heating mechanism of the tankless heater.

I know the newbies wouldn’t be getting things right and might be thinking what useless thing am I blabbering, right?

Tankless water heater needs to first heat the water before it supplies to the fixture, unlike the conventional water heaters that comprise of the tank full of hot water ready to get piped to the fixture.


You don’t have to worry at all as I would be walking you through the nooks and corners of a tankless water heater so that you can guide other house owners as well if such problems persist.

Let’s first understand what is a tankless water heater, and how does it work?

First thing first, a tankless water heater is a device that provides you with an endless supply of hot water on-demand basis.

As the name suggests, a tankless hot water heater doesn’t comprise a tank so the standby heat loss to the environment is almost negligible.

Secondly, a tankless water heater expedites the heating process ONLY when you require hot water and doesn’t use anything for storing hot water.

There are mainly two types of tankless water heaters depending upon the types of fuel.

Mainly, tankless water heaters are of electric and gas types.

The gas tankless water heaters are further segregated into the natural gas water heaters and propane gas water heaters.

On the basis of the location of installation, the tankless heaters can be divided into indoor tankless water heaters and outdoor tankless water heaters.

I did an online survey to find out how much additional time a tankless water heater takes as compared to its conventional counterpart.

The response I got was bizarre.

Unlikely, my expectation the response was very uneven, and to draw a conclusion wasn’t possible.

So, after doing some brainstorming I along with my team came to the conclusion that we would be floating a questionnaire to our clientele so that we can get some real response.

This time things worked perfectly fine, and it was easy for us to go back to a particular client as ask the reason for a particular response.

So, as per the response, we found that most of the clients agreed that it takes somewhere between 20 seconds to 30 seconds more to get the hot water as compared to a conventional tank-styled hot water heater.

However, some of the clients said that they had to wait for more than 30 seconds in the cases wherein the fixture was located very far away from the centralized heating system.

Well, if you’re also one of those facing a similar problem then my advice to you would be to install an under-sink tankless heater for that specific fixture.

Moreover, most of the under-sink tankless heaters that we’ve reviewed so far are small, compact, sleek designed, so you can install them under the sink or in its vicinity without any hassle.

Unfortunately, you end up wasting a lot of water while waiting for the hot water to arrive.

If you sum up the amount of water that gets wasted for the 20 second wait time for the entire year, then only you would be able to realize how much natural resource you’ve waste unintentionally.

So, is their any solution to get rid of it?

Definitely, YES.

The solution is related to the hot water pump so if you’re hearing the term for the very first time, then please allow me to explain the significance of a hot water heater.

Well, there are tankless models that come with high-quality advanced technology-equipped hot water pumps that are designed specifically to help you get hot water faster.

These types of pumps are popularly known as “On Demand” hot water systems.

Pipe diameter and flow rate are the two parameters that significantly influence the hot water speed.

Whether you’re a first-time buyer or a seasoned professional, it is really important for you to understand that the sizing of a tankless hot water heater is very important in order to reap maximum benefits from it.

So, if you’re wondering what size tankless water heater would suffice your hot water requirement, then you can read this article on tankless water heater sizing.

For example, buying an underpowered tankless water heater wouldn’t be able to suffice your hot water requirements.

Similarly, buying a tankless water heater that has much more capacity would only be a cause of concern as you’ll sooner or later definitely, figure out that electricity is getting wasted unnecessarily.

So, always look for that tankless water heater that is neither too large nor too small.

When you have a faucet that spews out 6 gallons a minute your wait is pretty small.

For example, a 1/2 inch diameter pipe 63 feet long holds a gallon of water.  So if your fixture allows water to flow at 5 gallons per minute, it would take only 12 seconds for the water to flow through the 63 feet of pipe.

If you have a low-flow faucet at the sink which only allows a maximum of 1 gallon per minute, it will take 60 seconds for the water to reach the fixture.

On top of it, especially in the cold climatic conditions, the pipe becomes too cold and it absorbs the hot water temperature in order to become hotter which further adds to the wait time.

Tankless Water Heater Operation

Trust me, I loved the working mechanism of a tankless water heater as it gives so much feasibility to the unit.

You don’t have to get scared that in the middle of the shower the hot water will go for a toss.

In the layman’s language, you can think of a tankless water heater as a coil of pipe with a burner under it.

And, since the heating process is a real-time affair so the water needs to be in contact with the heating element for some time in order to achieve the expected output temperature.

Well, you need to understand that when you turn on the faucet, the water in the middle of the coil wouldn’t get sufficient exposure to get heated to the desired temperature.

In fact, it is important for the water to travel through the coiled-up pipe in the unit so that it achieves the desired temperature.

Are you also suffering from slow hot water problem?

Well, if I’m not wrong then many of the newbies face the slow hot water problem, and the main reason is, they aren’t well educated about the functioning as well as the solution to certain problems.

Let’s figure out the best way to deal with the slow hot water problem.

We can pump the water in a loop from the outlet of the heater through the hot water piping and cold water piping back to the water heater inlet.

Moreover, if you’ll turn off the pump just before hot water reaches the faucet, then chances are rare that you’ll get the hot water into cold water piping, and as a result, the hot water will arrive quickly.

So, as soon as you hear the pump shut-off you can turn on your faucet.

And, the best part is, water wastage would be minimal.

Most of the instant hot water heaters that we’ve reviewed so far on this blog usually put a small pump at the farthest fixture from your hot water heater and connect them between the hot and cold water lines.

The better option would be to install an under-sink hot water heater at the farthest sink so that you don’t have to face cold water issues at all.

In fact, the pump comprises the temperature sensing element that shuts the pump off as soon as an increase in temperature is detected.

And, this makes it lots easier for the hot water from getting into the cold water line.

However, you would be needing a power outlet under the sink to plug the pump into.

The same thing you can follow for the farthest shower or any other fixture.

Push-Button Hot Water

So, whenever you want hot water, all you need to do is just push a button, and the pump would start delivering hot water to your fixture.

In simple words, the device would act as an environment-friendly device as wastage of water in the process of getting hot water would be minimum.

And, if you’re buying a good-quality tankless heater from the brands such as Rinnai, Rheem, Noritz, EcoSmart, etc, then chances are very high that your model would have got remote control accessories to activate the pump from other sinks that may benefit from the same pump.

Nonetheless, all the systems wouldn’t work with a tankless water heater.

In fact, a standard circulating system will not work so you need to be careful regarding the selection.

Make sure that you’re using an “on-demand” system else you’ll end up losing your warranty.

It goes without saying that a tankless hot water heater comes with a high upfront cost because of the advanced technology and other idiosyncratic features that it is equipped with.

However, if you’re a family of four people then you can expect to save up to 10,000 gallons of water every year.

In direct, you’re saving money, and in the longer duration, the tankless heater will definitely, pay for itself.

You also need to understand that reduced energy usages reduced the amount of gas being released into the atmosphere.

Wrapping Up

First and foremost, I would like to thank you for being with us till the end.

Secondly, I hope we were successful in satisfying your search intent of why does it take so long to get hot water from my tankless water heater?

In case, you still have some doubts or queries then feel free to reach out to us.

Lastly, share this piece of information with the ones who are in need of it.

After all, sharing is caring, isn’t it?

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