Best Tankless Gas Water Heater Reviews & Brands

Any inventions that can support humans’ need nowadays are considerably important. So is tankless gas water heater. It is not a secret that water is the most valuable commodity that humans can ever consume. Hence, when there is a chance to make the most of it, why do not we give a shot?

Just like its name, tankless gas water heater comes to heat water. Without any use of a storage tank, it will precisely heat water. There are many tankless gas water heater products available in store nowadays.

In case you are looking for one, here are the 5 best natural gas tankless water heaters you can bring home.

Top 5 Best Gas Tankless Water Heaters

These are five of the best ones you should consider buying:

Rinnai RUC98iN

Main Feature:

The heater comes 10 inches depth, 26 inches height and 18,5 inches width, with a weight of 61,7 pounds.

This heater provides around 0,95 energy factor for both propane and gas.

The temperature range of this heater is between 98°F–140°F.

The water heater comes with an Ultra Low NOx and 4 GPM Activation Rate.

The flow range of the hot water you can run with the machine is around 0,26 – 9,8 GPM.

Maximum and minimum natural gas with its gas rate input of 15.200 – 199.000 BTUs.

This water heater provides numerous venting options, which can be installed on Concentric PP or PVC.

Four various controllers are available such as MCC-91-2US, MC-91-2US and the other optional controllers are BC-100V-1US and MC-100V-1US.

This kind of water heater machine will likely do the job for a busy household that demands large amount of hot water.

This water heater is able to handle numerous operations at the same moment with a very little chance of running out, since its output is around 9,8 gallons in a minute. You can even do several amount of laundry with its dishwasher running at the same time. The water heater will not drop its temperature.

With the size of 10 inches depth, 26 inches height and 18,5 inches width, this water heater comes in compact and pleasant unit, essentially smaller than a regular tank.

Comes with the Energy Star Certification, this water heater machine is undoubtedly very efficient in doing the job.

Its efficiency will allow you to save some cash for energy bills with the number around $417 only, compared to any other identical models that may cost you nearly $500 for energy bills.


The price of this water heater is relatively expensive.

Professional installation is needed to start with, which may cost some money.

This water heater uses either PVC vent or concentric.


With the price around $2.500 then comparing the pros and cons, we can agree that Rinnai RUC98iN is the best option you can get. Different region or country may charges different price, but it is totally worth it. The deal seems much better if you are capable to install the unit by yourself.

Its Energy Star certification clearly defines its efficiency in doing the job. You will not have to worry about the tax since you definitely keep saving four your future gas bills. For a household needs, Rinnai RUC98iN will do the magic for you.

Takagi T-KJr2-IN-NG

Main Features:

The water heater comes with 6,7 x 13,8 x 20,3 inches.

This type of Takagi machine comes with TK-RE02 remote control, which offers more convenience in operating the water heater.

Electric ignition controller and computerized burner are available to maintain the gas bills on the necessary limit.

Its compactness makes this water heater suitable for indoor installation.

This Takagi series is supported by a trouble shooting diagnosis codes, safety features for freezer and also heat exchanger feature.

On a 75 degree temperature of inlet water, this tankless water heater is able to run around 6,6 GPM in one minute.

This water heater is suitable for medium residential use and able to run up to 3 faucets at the same time.


This type of Takagi machine comes with instruction book for installation, with very detail step by step process of installation. It makes this water heater is likely easier to install and to run.

Compared to any other unit of Takagi, this very unit is arguably one of the lowest priced water heater machines. Most families decided to purchase this Takagi series for that very specific reason. Moreover, you will also save some expense since this unit is free from customer service.

In case you lost or broke some of the parts of the water heater, you do not need to worry since its parts are available in almost every market, including its remote control. You can buy it separately.


If you live in a small or medium residence, this Takagi unit can only work for two bathrooms to produce the most efficient water flow. That is why this Takagi unit is not really suitable for a large residence. The water heater will not work efficiently. It is either you purchase another unit of water heater or you purchase two of this Takagi unit.

This Takagi unit requires ventilation system, which has to be categorized as three stainless steel. However, ventilation will not really cost mush to support the water heater unit.


The two strength advantages of owning this Takagi unit are its low budget in its simplicity. If you live in a small or medium residence, this water heater machine will do the job for you. You can also install the unit by yourself since the guidance book is easy to follow. However, make sure that you install them correctly so that you will not need any warranty, since the warranty is valid only when the units are installed by professionals.

Takagi T-K4-OS-NG

Main Features:

Takagi T-K4 model comes with 8,5 x 13,8 x 20,3 inches size.

This type of Takagi unit is only capable for outdoor only.

This water heater machine comes with heavy duty heat exchanger which is built from commercial-grade copper, to provide more efficient heat transfer. The heat exchanger is designed with proper resilience to prevent any possible corrosion.

This Takagi unit provide numerous safety features such as, manual reset hi limit, a freeze protection built-in, a flame sensor built-in, a couple of outlet and inlet thermistors that will monitor the temperatures, and an overheat cutoff fuse.

Takagi T-K4 model is already qualified for the low NOx emissions requirement, meaning you the water heater not only save your expense but also environmentally friendly.

Since the water heater machine is designed for outdoor fitting, ventilation is unnecessary. This means you do not have to spend more extra cash to buy any additional parts.

When the temperature outside your house drops, the technology of freeze protection will make sure that the machine is still totally functioning.

Having an outdoor water heater also makes your house safer since there will be no risk of gas build up inside your house.

Takagi T-K4 provides outlet thermistors which ensure you constant supply of hot water since it will maintain the temperature steadily.

Its miniature size will not take your house exterior away, but rather it will blend in.

The output of this Takagi series is capable in delivering not less 8 gallons per minute. That is a plenty amount of hot water supply. It is plenty enough for having multiple showers, using the sink, operating the dishwashers, and even doing a load of laundry at the same time.


Basically, all Takagi series have one main disadvantage; it is about keeping the warranty. As you know, if you install them by yourself, all kinds of the warranty become invalid. Takagi themselves only license few professionals who may be hard to find.

Another potential disadvantage is its electric ignition. In case your house is prone to any power blackout, the machine will take a while to produce hot water until the power is fully restored.


For the price around $600, Takagi T-K4 is a great option for a small family to produce unlimited amount of hot water flow. You can do a load of laundry, take a shower, and run the dishwasher at the same time without any worry. Just have to make sure that you install them correctly.

Noritz NRC661-DV-NG

Main Features:

This Noritz unit comes with 6,7 x 13,8 x 23,6 inches size.

The temperature setting of this water is ranged from 100 to 180 degree Fahrenheit. It has 14 options in total.

The thermal efficiency level of this Noritz series is up to 84%, normally for all models.

Noritz NRC661-DV-NG is supported by computerized system, which provides self-diagnostic on board to operate the machine.

This type of water heater machine comes with battery back-up, as well as recirculation mode and digital remote control.


Talking about the capacity output of hot water, Noritz NRC661-DV-NG can deliver not less than 6,5 gallons in one minute. That amount of unlimited hot water is enough to do a load of laundry and have multiple and simultaneous showers at the same moment.

Not only the unit itself is inexpensive, this Noritz water heater will also help you to reduce your monthly bill as well as energy use since the Noritz NRC661-DV-NG has got the Energy Star certification.

One sure thing that people think about before purchasing a water heater is about its installation. In that case, you do not have to worry since this Noritz NRC661-DV-NG is literally easy to install by any skillful individual. The machine comes with an instructional book that provides all you need to know and to do about the machine.

Any high-temperature vent is unnecessary since this Noritz unit does not require one. That kind of demand is really difficult to find in some places.

Just like any other water heater machine, any kinds of warranty will turn invalid when you decide to install them by yourself. Not only that this machine is easy to install, the professionals who are licensed by Noritz are not hard to find, in case you want to keep your warranty valid.


Since it is almost impossible to find any negativity from this unit, the only disadvantage from the Noritz NRC661-DV-NG is the price. For some people, Spending money around $900 for a conventional water heater type is too much. However, it is still far from the water heater with the most expensive price tag on the market. Hence, the price is not really a problem.


If you have laundry facilities and three bathrooms at maximum in your average household, this Noritz NRC661-DV-NG unit is a proper choice considering its simplicity. Once again, this price is far from the most expensive machine on the market.


Main Features:

The Heat Condensing Body feature in the machine is available to ensure that the main body of the machine will not get affected by any causes such as corrosion or rusting.

This Rheem RTGH-95DVLN is followed by a digital remote control that will assist you to operate the machine digitally, which ensures you constant comfort.

As one of the most significant features, EZ-Link Wire is provided to connect multiple separated tankless units where each other operate as a single unit.

This type of Rheem unit comes with half inch of compatible pre attached gas line mode.

This Rheem machine can perform up to 8.400 mean sea level efficiency.


This Rheem unit comes with freeze protection that will make sure that the machine will functionally work even in an extreme cold temperature. This feature can deal with the limit temperature of -30 degree Fahrenheit.

Every water heater product with Energy Star certification should not be doubted. So does this Rheem RTGH-95DVLN. Not only that the machine is friendly to the environment, you must also be fancy of its efficiency level.

One of the most crucial points in setting up a tankless machine is about the venting. In this case, this Rheem unit can be installed anywhere; inside or outside.

The Self-Diagnostic System in the machine will reduce your job since it will constantly check its condition from inside.


Compared to other units, you may find this Rheem unit is not really easy to install. Therefore, you will need to spare some expense for the installation. However, it does not cost much and also you will not find any difficulty to find them.

Instead of runs on electricity, this water heater runs on gas. Therefore, you will need to make sure regularly that there is no any leakage.

This unit may not be working for those who live in average households. The price of this unit indicates that this unit is suit more for larger households that demand unlimited supply of hot water.


Considering its system in price, Rheem RTGH-95DVLN will work better for large households. The price of $1.300 is too much to afford for small households. However, that does not mean that the machine will not work in small households. Some projects are sometimes is run in small households.


For those who live in an extreme cold temperature, owning your own tankless water heater machine can be a necessity. Not only that it offers you comfort in your daily life, tankless water heater machines can also efficiently help you doing your work.

The most important thing is to decide what your need priority is. Owning a tankless water heater machine can also be an investment in the future. Whether you live or work in small or large households, always note that a friendly environment and efficiently working machine is always preferable.