Best Tankless Water Heaters

Updated March 17th, 2020
tankless water heaters
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Do you want your home to be up-to-date with the latest technology? Are you remodeling your kitchen and you are thinking of upgrading it? Or, do you simply need a tankless water heater – gas or electric. Either way, we’ve put together a list of the best tankless water heaters, based on countless hours spent on reviewing dozens of tankless water heaters.

These water heaters are an excellent alternative to the traditional ones, and they don’t take up as much space as solar pool heater . It has also been proven that over time, they end up saving a lot of money. They are more energy efficient and they make your kitchen look better too. In most cases, this is the best option – especially if your kitchen is limited on space.

Tankless water heaters get the job done by warming up cold water as it flows through the device. They use either electricity or gas. You should know that most of them can heat up to five gallons of water per minute. From these types, gas heaters are prone to having a higher flow rate, almost five gallons. Electric heaters, on the other hand, can be more energy efficient, but fail to provide hot water fast enough.

One of the greatest benefits for having a tankless water heater is the fact that they have a great chance to save you some money. We all know that heating water means energy consumption . However, the best available tankless heaters and portable generators are made having efficiency in mind. This is how you know that they will save you a lot of money by using much less energy.

So, if we have your attention so far, it’s time to learn more about tankless water heaters! To help you make the right choice:

Our List of Best Tankless Water Heaters

1. EcoSmart ECO 27

EcoSmart’s ECO 27 electric tankless water heater takes the #1 spot on our list, because it can actually save you up to 50% off your regular water heating costs. This is because it has a very unique design for using electricity. The one we reviewed was fairly easy to install, too.

Although this device is very small and compact, you can still rely on it’s performance. It can be put practically anywhere. However, it also has some superior features. For instance, it has a digital control which will let you choose the temperature in one degree settings. This is how you can precicely choose the water temperature according to your own individual needs. Asides from being energy-efficient, it is also reliable and very durable. You know that you will be able to rely on it because the inside parts are very easily replaceable. So, if it somehow gets damaged, you shouldn’t throw it in the garbage. Just find the proper stainless steel or copper component and you can fix it in no time.

All in all, with a tankless water heater like the Eco 27, you end up saving a fortune. This is probably the most useful and energy-efficient water heater you can get. Dishwashing will be a much easier task too, and you won’t have to make a whole parade around it.

Pros Cons
Most efficient heater on the market

Replaceable inside parts

Durable and reliable


Very compact

Not very durable parts, might need changing

2. Rinnai RUC98iN Ultra Series Natural Gas Water Heater

We all know that tankless water heaters are designed with the purpose to be energy efficient. Still, some exceed these expectations and achieve more. They give the same experience as if you had a traditional water heater. This Rinnai water heater we are talking about offers the exact superior experience. This heater operates on a natural gas, which is exactly why your energy bill will be even lower than you would expect.

The manufacturer, Rinnai has made sure that the RUC98iN has two different venting options. Namely, you can choose from twin-pipe and concentric-PV. For you as a user, it means that you should select the one that is suited for you. Of course, one can be easier for you to install. So, after doing this, you will get hot water for all purposes from the tankless water heater.

If you have a large household with a lot of members, this heater will come in quite handy. After all, it can supply really hot water to numerous faucets. You can even wash dishes with the faucet and someone can shower at the same time – all of them will have enough supply of hot water. There won’t be any interruption.

If you want to talk numbers, the Rinnai tankless water heater provides hot water at a flow rate of 9.8GPM. In a single turn, this rate can stem the natural gas intake which can vary from 15,200 to 199,000BTU. Of course, this is only if you pump enough gas for its purpose.

Last but not least, the Rinnai RUC98iN Ultra Series tankless water heater is very environment safe. It has a 0.95 efficiency rating which means that it is completely safe for the environment. The included installation manual from the heater we reviewed came in handy, also.

Pros Cons
High energy-efficiency

Provides a tremendously large amount of hot water

Can be used for numerous faucets or showers at the same time

A bit bulky

Can be somewhat hard to install

3. Atmor AT-D18TP-AZ

If you think about getting a water heater that is all-purpose, this one must be on your short list. Possibly, even in your shopping cart. When you go through reviews, you will see that only a few things are essential for a tankless water heater. For instance, it should be easy to operate, compact, and it should be able to provide a good flow rate considering its price.

During our review, we found out that the Atmor AT-D18TP-AZ tankless water heater has a lot to offer, and it can pretty much teach higher price tag heaters a lesson. This water heater offers a feature which simply changes the water-heating game. It actually has a water sensor. For you as a user, it means that you can demand hot water, and at the same moment, this sensor starts heating water for the future. Additionally, if you turn off the tap, the device will automatically turn of the heating. So, it saves you an incredible amount of money on both the short and the long term.

Talking about user-friendliness, we couldn’t help but notice that this water heater has an abundance of it. It is an instant water heater and it isn’t complicated at all. Also, it doesn’t have fancy and confusing parts. It has a single know below the digital thermostat. So, regardless of how much technologically illiterate you are, you will find that using this device is a piece of cake. Even a kid would operate it. More importantly on this manner, it is also very safe to use. Even if your kid uses it, you don’t need to worry about them getting their hands burned. Also, on the same subject, all of the internal components are certified via IPS4. This means that the internal components are always dry and safe for using.

Pros Cons
Excellent flow-rate


Safe to use

IPS4 certified

Easy to operatee

Digital temperature control

Doesn’t provide hot enough water for some purposes

Flow-rate not enough for large households with a lot of members

4. SioGreen IR260

Do you want something out of the ordinary? For those who want something more than just a water heater, the SioGreen IR260 is here. It will also make sure you keep getting clean water for the safety of your family. This tankless water heater uses an infrared quartz element to heat the water. However, it also prevents the natural metallic taste other heaters can create using components made of metals like copper. In general this is the feature that keeps the pure taste of the water. Still, it achieves the same performance and water temperature options for tankless water heaters.

This device is equipped with a built in maintenance free design and temperature control for your convenience. Another benefit you get from the infrared heating is the fact that the water never comes in touch with any quartz element. This means that the chances of getting corrosion and rust are put down to a minimum. Nothing will be able to wear down the inside of the device. Additionally, this comes in helpful in preventing the calcium and lime scale build ups. All in all, you won’t need to clean the interior parts of the tankless water heater ever.

All in all, this water heater is an excellent purchase because it is much more than a regular heater. Although it is an investment, it is surely an investment worth making. It pays off on the long run. Both your budget and your health will see the consequences of it. So, don’t hesistate to get a device that can satisfy all of your family’s needs.

Pros Cons
Easy maintenance water heater

Clean water options

Very useful features

Functional and durable design

Good construction

A bit bulky

Good construction

5. Eccotemp EM-2.5

If you live in an apartment or a small home, the Eccotemp EM-2.5 tankless water heater will do the trick for you. This water heater can satisfy all the needs that you can have in a smaller living space. The reason for this is that it has the limitation on the flow-rate of the water.

The manufacturer created this water heater with the purpose of it serving the people living in smaller houses. So, if this is the case with you, you won’t have to overpay for a unit you won’t actually need. Although this option is very fast for smaller living places, don’t overestimate it. It won’t be able to be functional in larger apartments. So, consider other options if you are doubting about this.

The EM-2.5 is best at point of use heating. Also, this means that you can put it on places which are suitable. For instance, some ideas can be under the sink. Or under the shower. This way, the unit will heat the water which is in that exact location.

An alternative to buying a larger and more powerful tankless water heater is to buy several of the Eccotemp EM-2.5. This way, they will all make sure you get the coverage you need. And you will save a lot of energy. Although it is not very powerful, it still is functional and it gets the job done. More importantly, it doesn’t cost you more than it should. So, we can conclude that this water heater is simply a safe play. It does come with a manual you case.

Pros Cons

Energy efficient

Easy installation

Durable materials

Cheap considering its performance

Possibly not powerful enough

Limited water-flow

6. Bosch Tronic 3000

If you are budget conscious and want to get a budget water heater, the Bosch Tronic 3000 is a heater to take into consideration. This useful device is an even smaller option for point of use water heating device. Especially if you consider it to other devices that made it on our list. Still, it works in a very simple manner which is the best thing about it. The beneficial feature we are talking about includes a single power cord. You simply put it into a regular wall outlet, and afterwards you are good to go.

The manufacturer designed it in a very specific manner. It should be able to help the people like you, who are practical and conscious. It is very small, so it can be easily moved from one point to another. This is why it is an excellent for those who need to heat water in mobile homes, outside kitchens, cabins or boats. You use it, and then pack it and take it home. A piece of cake, right?

The Bosch Tronic 300 can be bought in three different sizes. They range from 2.5-7 gallons. However, we should mention the design too. Like many other water heaters which are tankless, this one can be stored easily and anywhere. You can choose, put it in a cabinet, under the sink, or even on the wall. It has an included wall bracket. From the moment you plug in the heater, you just hook up the cold water line. Afterwards, you will get hot water for the specific location you chose previously. This option is excellent for those who are constantly on the move and have adventurous trips.

Also, since this is such a popular company, any necessary repair parts in case of issues with this electric tankless water heater can be easy to find.

Pros Cons
Easily portable

An effective alternative to other heaters


Multiple sizes to choose from

Reputable manufacturer

Plenty of positive customer reviews

Not a lot of features

Doesn’t heat up too much water

7. Stiebel Eltron Tempra 24 Plus

Nowadays, electric tankless heaters are very common. Especially because of the fact that they offer energy efficiency and that they have an easy installation process. Considering that no natural gas is needed, most of these will just need a power outlet. Regrettably, having a design that is energy efficient can mean the heater has a problem with high power demands. This is definitely not the case with the amazing Stiebel Eltron Tempra 24 Plus electric tankless water heater.

What makes this tankless water heater special is the fact that it has a flow rate of up to 4.68 gallons per minute.  This is why, it can stand out from the crowd, even if we compare it to gas-powered heaters.

Asides from the presence the higher flow rate, the Stiebel Eltron heater also ensures you have improved control. Especially if you want to know what happens with the flow and temperature of the water. For you as a user it means that you will be able to can reduce the flow. This way, you can actually save more energy. You can even set the temperature exactly according to your personal needs. Amazing, right?

If you don’t like such features, there is always the self-regulating thermostat you can rely on. This one has the basic features which will help you make a right decision. The Eltron 24 Plus is easy to install, and comes with a handy manual.

Pros Cons
Excellent performance for an electric tankless water heater

Great construction

Easy-to-use and to mount

Lacks some more flow for heavy-duty usage

Cannot be used in larger households

8. Westinghouse 11 GPM

And, last but not least on our list is the Westinghouse 11 GPM tankless water heater. This awesome product can achieve double the average flow rate. This is if we compare it to most heaters which have the ability to heat up to 11 GPM. So, to conclude these statements, this is a single heater that can do it all. Regardless of what your hot water needs are like, this heater can surely handle them all.

If you don’t have a lot of knowledge about installation and mounting processes, we have good news. The Westinghouse 11 GPM is installed in the same way like the regular water tanks. So, although you should get a professional to do it, you know that it will be done. After the proper installation, your unit will be good to go. Design-wise, we should mention that this tankless water heater features a dual stainless steel in its construction. This means that it is resistant to corrosion. It is also very durable and resists regular wear and tear for a longer period of time.

Considering that you are using gas, you should know that the heater has Energy Star certification. So, you save your budget from expenses and you have an energy-efficient device.

Pros Cons
Excellent design – inside and out


Uses natural gas

Energy Star certification

Needs professional for mounting

On-Demand Water Heater Buying Guide

To make an informed choice for a tankless water heater, you need to have a lot of things into consideration. There are numerous debates about these subjects and they are all equally important. So, think about gas or electric, your demand of hot water, the climate of your area, the costs of installation and what. Don’t forget to consider your budget and see what you can actually buy with it.

We are all aware that not everyone needs a monster of a water heater. And the opposite is true too – not anyone can get away with getting a compact water heater. So, before you make the ultimate purchase, here is what you should consider:

Gas vs. Electric water heater

The first and most important thing to consider is the type of the water heater regarding what it uses. Both of these options have their own pros and cons, and it is up to you to make a decision.

For instance, natural gas or propane is almost always significantly cheaper than electricity. So, if you use it on the long run, gas heaters are much more efficient and budget-friendly. Also, they are significantly powerful. They are even faster throughout the overall performance. So, if you live in a larger house with a lot of family members, this is probably the choice you should make. ,

On the other hand, their negative aspect is the fact that they are pricey at the beginning. The units cost more than those who run on electricity. And, you have an additional investment to make – venting. Indoor models require venting, so, you need to invest in the vent installation process. So, this makes them a lot pricier than those who run on electricity. Also, they are prone to being harmful to the environment. So, if you want to environmentally-responsible or if you plan on to installing solar panels, it would be a better choice to get electric water heater.

Take into consideration which choice makes sense in your general scheme of utilities. For instance, if you have a propane or natural gas line in your household, surely, go with this choice. Think about what you want your home to be like, and use this as a base for your decision. You won’t regret it if you get exactly what you wanted.

Hot Water Demand

When you buy a tankless hot water heater, you notice one thing. You get a list of the maximum flow rate in gallons per minute (GPM). Basically, in simpler terms, this is the maximum volume they can heat properly. For instance, the showers have the greatest flow rates of any appliance. Their high-flow vary from 2.5 to 3 GPM. Also, showers with low-flow fail at around 1.5 gallons per minute. So, you can choose the unit based on how many showers it can power at the same time. This is one way to do the math.

You need to have into consideration that a busy household needs to have several hot water appliances working at once. If this is the case in your household, you will probably need to think about a larger heater. It should also have a greater power and a larger capacity.

It is well known that the smaller the unit is, the lower its GPM is. So, think about your needs, and think if the water heater can actually satisfy those. If you skip this step, you risk having to overpay. So, prevent yourself from obstacles like this one. Ensure your satisfaction with the purchase by doing the math and seeing if the water heater is suitable for you.


Although it seems like this isn’t important, it actually is an essential thing to consider. For example, in the northern parts of the world, the water has lower temperatures compared to the southern parts. This is why you should consider the area you live in and see the average water temperature from the tap. If you want to prevent problems from this, there is a solution. Round it up and buy a unit which has a high flow rate, higher than what you need. So, this way you make sure that you get the performance suitable for your individual needs. Also, even if the months get colder, you don’t risk having no warm water.

On the other hand, if you have a Mediterranean climate and warmer temperature throughout the year, you are lucky. You might even have a chance of getting away with a smaller unit. This will surely save you a lot of money. After all, you won’t pay for a device or a unit you don’t actually use to the maximum.  If your tap water is mild, you will also save energy because your heater won’t need to be working too much.

An another thing regarding the climate you should consider is the type of your tap water. If your water is prone to causing damage from calcium and lime scale build-up, you should be careful. It is recommended to get a suitable tankless water heater for your local water. So, if this is the case with you, think about resistant tankless water heaters for your needs.

Installation costs

As we said before, gas tankless heaters are rather expensive to install. But this doesn’t mean that you don’t spend any money on installing an electric one. Both of them have installation costs – in money or in energy. We don’t suggest installing it on your own because of the possible negative outcomes.

Hire a professional and ensure that the job is done properly. After all, this is a unit you will use on a daily basis. However, talking about our tips for buying a water heater, there are other things to consider. There is a different price for different types of water heaters. And they all have different designs and features. Make sure that you have access to a professional who is skilled at installing these types of heaters.

Make sure you put aside some money for this task too. So, when you are considering your budget for the purchase, these costs should be included into the overall sum. This way you save yourself from any issues and discomforts.

If you’re feeling up to it, you can install your water heater on your own but be sure to follow the instructions properly. You can this video as a guide but more importantly, follow your own manual.

What’s the Best Instant Water Heater for You?

After looking at our list of the best tankless water heaters, we hope that we have helped you make a better decision. In this part of the article, we’ll talk about the best instant water heaters and how to know if one is right for you.

The first things that you need to know in order to make this decision are the features of the model. So, when you are looking for a suitable unit, see the features it has. Afterwards, take a look at your own needs. If they are compatible, this is a potential purchase for you. But don’t get fooled and get the first one you get offered. Each household is specific and you should balance out the specifications and the features of the unit.

For example, some are cheap and suitable for smaller sinks and showers. Others are good for medium households with no more than 5 people living in them. On the other hand, some offer features which are budget-friendly or more environmentally-friendly. It all depends on your own personal preferences.

So, the best instant water heater for you is the one that satisfies your personal needs. In order to make a good decision, you must know what you really need. This way, you have a guarantee that you will never end up disappointed.

Why would I choose a tankless water heater over a conventional storage boiler tank?

There are several reasons why you should consider an instant water heater. For example compared to regular storage boiler tanks, these are very budget-friendly. Especially in the long term. They save you a lot of money, and the difference is easily seen.

Although they are expensive to buy, even more expensive than regular boilers, there are benefits. They are even more expensive to mount. But all of these costs are only in the short term. With an instant water heater, you will never heat water that ends up unused. Your electric bill will see the difference in a very short manner. So, although expensive, these water heaters are a true investment.

Another reason to get a tankless water heater is the fact that they are much more compact. Conventional storage boiler tanks take up a lot of space, and they look very bulky. Unlike them, the instant water heaters are very small and they even look cute. You will find them very beneficial if you don’t have a spacious kitchen or shower. These units also make the home feel a bit tidier than it would with a regular boiler. Especially if you get a unit which gets mounted at the point of use. You can put it under a sink or in the cabinet – and you are good to go. Turn the tap and you get hot water, instantly.

Should I replace my existing water heater with a tankless model?

This is a question that we all have on our mind from time to time. And we should, this is a part of the future and we must meet it. Although there are pros and cons to both options, the answer to the question is “Probably yes”. As we mentioned before, there are several things to be taken into consideration. After all, it depends on your own circumstances. However, even if you are happy with your electric bill, an instant water heater is a good choice. It will be even better – we promise.

Regardless of how small or large your needs are, instant water tanks prove their worth on the long run. As an alternative to the regular water tanks, these are incredible. They have modern and up-to-date technology which can face all obstacles of modern life. They are getting even better-looking and more aesthetically pleasing.

So, the answer to the question is that it depends on your personal needs. If after taking into consideration the most important things about them you decide that you need one. Yes, replace your existing water heater with a better one – an instant one. You won’t regret this decision. And your wallet will see the difference too.

How do I know how much hot water I need?

We said it before, you need to determine how much hot water you need in order to make a purchase. Although this looks like a complicated thing to do, this is not really the case. For example, a good way of determining is that you need around 3 GPM or a single bathroom. If you live in an average household, this much of hot water at the same time is more than enough. For example, if someone is showering, they would use around 1.5 to 2.5 gallons per minute. This way, you get an abundance of water

If you don’t want to risk it, we have another suggestion. Take a look at the devices in your house which uses water. It always has a rating from the manufacturer. If you cannot find it on the unit, search the documentation or the website of the manufacturer. Again, this number is also shown in gallons per minute. It shows you how much water the unit needs in order for it to function properly. Just write down the numbers, add them up and you have a number. This is the number of GPM you need to look for in a water heater.

An additional tip regarding this is to go a bit higher than what you think. You don’t even want to know the issues you will have if you don’t have enough hot water when you need it. It is frustrating and annoying, and this is exactly why you must prevent it from happening.

Conclusion – Choosing the best instant water heater

Instant water heaters seem like a gift from above. These little devices are small, functional, and practical. They also change the way we think the world works. So, getting one is never a bad option. All you need to do is some research and get the proper one. Having a tankless water heater proves itself to be a very good thing. You don’t spend energy, time or money on such things. You won’t even have to think if you’ve turned off the water heater each time you go out. And we all know how frustrating this is.

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