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Best Tankless Water Heaters

Best Tankless Water Heaters

Best Tankless Water Heaters

There are tons of reasons that you might be looking for a new water heater for your home. Perhaps your old one has finally kicked the bucket, and you need to find a good replacement as soon as possible.

Maybe you've moved into a new house, only to find that the heater that was already there is about to break down, and winter is around the corner.

Do not panic, especially when it comes to looking for the right boiler to heat your home. You don't want to impulse buy the first model that looks great, only to find out that the new one is also trash.

So, with that in mind, take a deep breath, make a note of all the things you need your new heater to do, and sit back as we show you some of the best tankless water heaters out there.



If you're looking for a water heater, then you want to be able to know that it is right for your home. You want to know if it can stand up to a lot of use from all over your house, and still keep the hot water running.

In that case, if you're looking for a heater that you know will be able to handle that massive workload, then you should consider taking a look at the RUR98iN from Rinnai. Their water heaters are some of the best in the business, and the same goes for this model.

Rinnai's innovative technology provides an unlimited supply of hot water while maintaining a very high quality of life. Rinnai's condenser system offers superior performance by using two separate heat exchangers to maintain a higher level of efficiency.

The compact design allows it to fit in tight spaces, making it ideal for residential and commercial use.

With Rinnai's new TRW tankless rack system, installers can turn on the tap and immediately enjoy hot water, without waiting for the unit to warm up. This reduces energy consumption and saves time.

It can also be used in combination with a standard Rinnai boiler, increasing its versatility.

Installation was fairly easy when we tested it for ourselves. We did have some trouble getting the gas hookup done correctly, but that was a matter of being careful to follow the instructions.

Everything worked perfectly after that! Definitely a great option for those looking to heat medium and larger homes.


  • High flow rate for a tankless water heater - This boiler has a GPM rating of 9.8, a perfect rating for pretty much any standard home you might find out there
  • High levels of efficiency - With an energy factor of around 96%, one of the best on the market currently, you know that nothing is going to waste when this model is heating your home. All thanks to its dual heat exchanger, you won't be wondering where all your heating bills are going with this feature!


  • A pricey model - This model is certainly at the higher end of most people's price ranges. But with its long-term energy-saving features, you may find yourself saving a few dollars in the long run. And when it comes to heating your home, do you want to be trying to cut corners on something as important as this?

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If efficiency is your main concern when it comes to a boiler, especially if you are running on electricity to heat your home, then Rheem's RTEX-18 is just the plucky little water heater for your home.

The Rheem RTEX 18 offers the best of everything. With Rheem’s exclusive self-modulating technology, you are assured of the highest level of comfort and energy savings. The Rheem RTEX18 delivers the lowest possible flow rate while maintaining maximum heat transfer efficiency. This means less water usage and lower operating costs.

In our preliminary research, we wanted to test Rheem's external digital thermostat with a 7-day memory to replace an older manual thermostat.

The old thermostat we were using in the test did not work correctly and would shut off the heater during the night when it had been set so that it should have been running. 

With the new thermostat installed, the problem quickly went away. So for those wondering about the thermostatic control function, the unit works as advertised, and is easy to install.


  • Compact size - No need to worry about leaving this heater in a darkened cellar because there's nowhere else to install it in your home. Being roughly only the size of two laptops together, weighing less than 9 pounds, this water heater will be both easy to store in any room in your home, as well as light and easy for installing in the first place!
  • Excellently efficient - The copper immersion system that it uses to heat your home is ideal for those smaller homes that want to be to get the temperature just right for them, within a 1-degree level of accuracy.


  • Not for larger homes - Although it is always difficult judging how much hot water boilers can generate for any home, it seems that this boiler is only really able to supply one or two faucets or showers with hot water at most. So this isn't an ideal make for those larger homes with bigger families. Still, for a 2 to 3-person household, this may be just the water heater you are looking for!

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Bosch has been making our homes warmer and safer for over a hundred years at this point, so you would expect them to be pretty good at it by now. And the Tronic 3000 water heater seems to prove it.

It's hard to imagine a kitchen without hot water. But now there's a new way to heat your home while saving energy. The Bosch ES4 Tronic 3000 Electric Water Heater makes it possible to have hot water instantly whenever you need it.

It provides a fast recovery rate and saves energy by heating water when required instead of constantly running the pump.

With Bosch's Energy Star qualified design, you get a water heater that's easy to install, use and maintain. It comes with a 3-year limited warranty and is backed by a 1 year extended warranty. Plus, it offers a 5-year anti-corrosion warranty.

This water heater installs easily into a standard sink using the included mounting bracket. Simply plug your existing cold water supply line into the water heater and connect your hot water line to the faucet.

The water heater heats water instantly - just add cold water and wait! No waiting around for hot water. 

We tested this particular water heater because we wanted to see how warm the kitchen area could be kept while cooking a meal in it. And we can say with confidence that this unit works perfectly!

It heats up fast and provides enough hot water to fill two sinks. We like the fact that there is no mess, and it takes up little space. It was easy to mount, and we love how quiet it runs.


  • A great boost to your current water heater - If you're looking for a way to get a little extra heat out of your faucet or shower. Simply install this near a chosen appliance in your house, and you can start enjoying that sweet hot water!
  • No extra help needed for installation - You don't even need professional help to install this boiler! With some good instruction and a little know-how, you'll be able to fit this heater into your home yourself!


  • Not ideal as a primary heater - Although it seems to function great as a way of giving your home a little heating boost, we have our doubts that this little heater is ideal to run a home's hot water supply all by itself. And with some reports of leaks being a potential issue for some buyers, you may want to think twice before committing to heating your whole home with this humble little unit.

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With 70 years of boiler-building under its belt, Takagi is a household name for a vital household product. And their T-H3-DV-N is a prime example of their excellent handiwork.

Takagi T-H3-DV-n was designed by engineers from Takagi America Inc., based in San Diego, California. It is a compact, energy-saving, multi-functional, high-efficiency condensing boiler.

The unit has a small footprint and is easy to install. Its performance is comparable to larger models, yet it is smaller and easier to maintain. In addition, its low noise level makes it ideal for use in residential settings.

It is equipped with a built-in electronic thermostat, allowing the user to set heating and cooling temperatures without having to turn on a pilot light. This allows the user to enjoy the benefits of instant hot water while keeping electricity bills down.

T-H3-DV-N is designed to meet the strictest environmental regulations for boilers, including the 2012 SCAQMDA rule 1146.2 for ultra-low NOx emissions. These stringent standards ensure that T-H3- DV-N meets the highest industry standards for efficiency and reliability.

We tested two of these units to see if its boast of being workable with more than one heater was true, and to our surprise, they were working great together!

They were easy to install, worked perfectly, and are sure to save you money on a heating and water bill. We recently installed them again to see how they handled being moved around, and they work just as well as they did the first time around.

Also, the integrated control panel is convenient because you don't have to go outside to turn it on or off. There are also some other nice little features such as a safety shutoff switch and an LED display. Overall, we would recommend this unit to anyone looking for a high quality, energy-efficient heater.


  • Easy to install - It won't take long to get this water heater up and running in your home. You'll be enjoying warm water in no time flat!
  • High water volume - It certainly lives up to its claim of having 'endless hot water in your home. With 10-gallons of hot water per minute, and an excellent flow rate to keep the levels up, this water heater gains and heats water just as quickly as it sends it to your shower or faucets. Absolutely a great choice for a home that loves a good shower and/or bath!
  • Surprisingly compact - For something that can put out so much hot water, you would assume that this heater takes up a ton of space. But with an 11.2×17.8×24.9 inch design plan, you'll be surprised just how easy it is to find a home for this unit in your home.


  • A slow intake at first - Although this isn't an issue once you've had it running for a short time, you may find that it takes a little while for this unit to heat up at first. This isn't a problem unique to this model (most indoor-purpose tankless heaters have this same obstacle they struggle to overcome). But if you're looking for hot water instantly, you may have to look elsewhere.

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If you're looking for a tankless water heater, then chances are that you're concerned about keeping your energy bills low.

A tankless water heater is a great way to conserve energy and reduce your monthly utility bills. The ECOSmart ECO 18 is designed to provide endless hot water while using less electricity compared to a standard tank water heater. This makes it a smart investment for homeowners looking to cut back on their energy consumption.

This particular model comes with a three-year warranty and requires a double pole breaker. An electrical panel rated at 200 amps should be able to accommodate this product. For more information on this product, call us at 888-844-2327.

EcoSmart ECO 18 tankless water heaters are built to last. They come with a limited lifetime warranty and are backed by the company’s exclusive customer service program.

The company has been delivering reliable products since 1999 and continues to lead the industry with innovative technology, quality products, and unmatched support.

The ECO18 comes equipped with a digital thermostat that monitors the temperature of the water flowing from the unit. It can adjust the output of the water-based on the temperature of the incoming water.

This allows the user to set the water temperature as low as 120 degrees Fahrenheit and as high as 240 degrees Fahrenheit. The unit also features a self-diagnostic system that lets you know whether there are any problems with the unit.

We chose the ECO27 for this list because it was the smallest size available, and we wanted to see how well it would fit into our limited space. It was easy to install and works great, so it's got great marks there!

We love the fact that there is no running water while it is off. No worry about the occasional leak or unwanted warm spurt from a faucet or shower when it isn't needed.

We don't have to worry about it getting contaminated or the buildup of rust. Also, we like the fact that it has a digital display so we know exactly how much hot water is flowing to each fixture. 

We also like the fact that it is extremely quiet. It doesn't make any noise and is perfect for sleeping next to. And, since it doesn't require a dedicated circuit, it won't disrupt your other appliances. Overall, we couldn't recommend this unit more!


  • Easy to operate - The LED screen makes it easy to see what level your boiler is operating at. User interface and ease of use can often go forgotten when designing a boiler, so it's good to see Ecopoitn get this right for its users.

  • Low cost - This is a solid option if you're on a relatively tight budget when it comes to looking for a water heater.


  • Unreliable in colder climates - We found that isn't doesn't quite maintain those great energy efficiencies and flow rates when this heater is subjected to colder temperatures. Although it doesn't seem to affect the long-term lifespan of this unit, having your hot water fail at a crucial time of year is something everyone wants to avoid. Ideally, you should only consider this boiler if you know you live in a temperate environment. Otherwise, you should look elsewhere.

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Buyer’s Guide

Fuel Type

There are three main types of fuel that water heaters use to heat their units: Electricity, Natural gas, and liquid propane. All these different types of fuel for your heater have different benefits for your home.

Electrical heaters are very efficient when they are working at their best, and tend to be cheaper when it comes to installing and purchasing them. However, they do generally perform less well in colder climates, which makes them unreliable in a cold snap.

Natural gas heaters are usually more reliable than their electrical counterparts but suffer from them being less efficient with their fuel, meaning that you'll likely be burning a lot of gas to heat your home. They also require special ventilation, as natural gas is toxic to humans if inhaled.

Liquid propane is generally harder to find than natural gas but does a similar job when it comes to reliability, as well as being environmentally cleaner with fewer emissions, as well as being much more efficient, burning approximately a third the amount of natural gas to heat the same area.

Flow Rate Capacity

How many gallons per minute does the unit deliver? You want to ensure that you are not going to be shorting out your washing machine with too much hot water.

Hot Water Capacity

Another thing to consider is how much hot water do you need? Do you plan on using the water heater once or twice a day? Or maybe even every single day?

Energy Efficiency 

This is very important because it is going to save you money on your electricity bill. However, you don’t want to sacrifice quality either. So, you can’t just choose the cheapest model.

Digital Display

Even though they aren’t as common anymore, some models still come with a digital readout instead of an analog one. They are easier to understand, especially if you are new to owning a water heater.

Safety Features

Most modern tanks have a built-in safety device known as a thermal cut-off system. They shut down the unit automatically if the temperature gets too high. This prevents fires and explosions from occurring.


Whilst this might seem obvious to some, you should keep in mind that different heaters will cost different amounts for different stages. There's the upfront cost of course, but then there's the cost of installation, which can change depending on the size and complexity of the heater.

And that's not even covering how much different fuels cost, and how likely their prices are to fluctuate!

Frequently Asked Questions

What Is A Tankless Water Heater?

A Tankless water heater is a great option for those looking to install a water heater in a smaller space. It heats your water instantly, rather than having to rely on a large tank full of heated water

This means that all of the energy used by the water heater is converted into heat and pressure, rather than cooling off and heating back up again.

Why Should You Buy A Tankless Water Heater Over A Heater With A Tank?

When it comes to the differences between these two models, it primarily comes down to efficiency and upkeep costs. If your current water heater has a tank, chances are your monthly energy bills will be higher due to having a larger tank to heat up.

If you're looking for something that requires little maintenance and doesn't need regular cleaning, whilst also saving on space in your home, then a tankless heater may be the way to go. It


These 5 water heaters that we have discussed are just some of the units that are available right now. But we hope that we've been able to give you some information about them and help you make the best decision possible.

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