Go back a few years, and you’ll see that almost all homes had traditional water heaters. Despite the fact they polluted the environment, consumed large spaces in our homes while also weighing heavily on energy bills, the lack of choices forced people to buy them. However, with the advent of gas tankless water heaters, the situation has now changed. Apart from occupying less space in our homes – since they are compact, the best gas tankless water heaters also weigh lightly on our energy bills.

Since they are more energy efficient, the best gas water heaters do not pollute the environment as much as their traditional counterparts. Therefore, whether you want to save money – or the environment, while also ceding less space away, you need the best gas tankless water heaters.

More importantly, after taking help from gas tankless water heater reviews, we have prepared a list of the seven best gas tankless water heaters. Consequently, no matter where you live – and how much hot water you require, this list has got something to offer. Take a look.

Rinnai RUR98iN Natural Gas Tankless Water Heater


Though not inexpensive by any stretch of the imagination, buying Rinnai RUR98iN – should you choose to do it, will mean you won’t have to search for any other best gas water heater, ever.

For, as suggested by its gas tankless water heater reviews, it has so many useful features that it will solve your problem of getting hot water once and for all. Features One major problem people have with cheap gas tankless heater relates to venting. Every heater has different venting requirements – meaning you need different pipes for everyone of them. It means repeated visits to the local market to get the pipes which fit.

However, with the Rinnai RUR98iN, you’ll never have any such problem. It offers two venting options: concentric and PVC, and you can use either or both depending on your hot water requirements. More importantly, the increase in the range of choices means you would be able to install venting with ease. After the vastness of venting options, it is the mammoth 9.8GPM flowrate of this heater which merits your attention.

Provided you are using both vents, 5+ washrooms will be able to get hot water at the same time. How is it possible, I hear you ask? Well, it has been made possible by the innovative recirculation technology used by Rinnai. Without requiring you to install an extra pipe for recirculation, this technology will provide a consistent supply of hot water 24*7.

Finally, reading the details of this heater, some of you might have wondered about two things: its effect on the environment as well as its compactness. Luckily, thanks to the 0.96 energy factor – which means a 96% energy efficiency, this heater won’t pollute the environment. As for space which it will acquire, as a mere glance on the heater might tell, it will require same storage space in your home as that of a small suitcase.


  • Mammoth 9.8GPM flowrate
  • Consistent supply of hot water due to recirculation capability
  • 96% energy efficiency
  • Compact
  • Gives two venting options


  • Ultra-expensive

 Final Verdict 

If you have a big budget for a best gas tankless water heater, the Rinnai Ru98iN won’t disappoint you.

Rheem RTGH-95DVLN  Direct Vent Tankless Gas Water Heater


If you loved the Rinnai RUR98iN for its flowrate – but hated it for the price, here is a low-priced option from Rheem which remarkably offers a similar flowrate but at a reduced price. Features While going through on demand gas hot water heater reviews for researching this article, I found out that – apart from venting problems, most customers were annoyed with the fact that they cannot install gas tankless water heaters indoor.

If you have the same complaint about gas heaters, Rheem RTGH-95DVLN will sort you out. For, the major reason why gas heaters cannot be installed indoors has to do with their vents. However, in this heater, both the vents have been designed such that you can install them indoors without any safety drawbacks. To demonstrate how user-friendly this heater is, three features come into play.

First, during the installation phase, it has a self-diagnostic system to help you get through the installation process with minimum fuss. Second, it has a digital display, which not only shows the temperature but also the maintenance codes. Yes, you’ve guessed it right, it gives you maintenance codes to troubleshoot the heater on your own when/if it malfunctions. Thirdly, no matter how safe the best gas tankless water heaters are, none of us like to touch them. And with Rheem RTGH-95DVLN, you won’t have to touch it to adjust temperature settings since it comes with a remote control. Use it, and you can operate it from distance.

Finally, if you have gone through gas tankless water heater reviews, you might have noticed people complaining that they don’t work in high altitude areas. The Rheem RTGH-95DVLN, however, has the capability to work as high as at an elevation of 9840ft.


  • Works up to 9840ft
  • Has a mammoth 9.5GPM flowrate
  • Offers freeze protection for temperatures as low as -30*F
  • Has a remote control and digital temperature display


  • You might have to hire a plumber to install it

 Final Verdict 

If you have agreed to spend so much on buying this heater, I assume paying a few extra dollars to the plumber won’t hurt. And if it doesn’t, this heater won’t let you remember its price tag for long. 

Bosch Greentherm C 1050 ES Propane Tankless Water Heater


Just to make sure you don’t accuse us of being bribed by Natural Gas mafia, we have decided to include a propane tankless heater in this review. Will this heater mellow your heart? Let’s find out.

Features To take the concept of the water heater to a whole new level, Bosch has provided the Greentherm C 1050 with a mobile app, yes a MOBILE APP. Though it won’t improve its functionality, this app will help you during the installation process by simplifying the sizing calculations. Worth a shot! If you weren’t impressed with the mobile app, you are bound to be enamored by the technology this heater has used to provide consistent hot water.

Keeping aside the technicalities, it has used a bypass line to make sure hot and cold water never encounters each other. Consequently, you won’t have to worry about cold water ruining your day while taking a hot bath. As for the water flowrate, you’ll love to know that this heater has a maximum flowrate of 10.7GPM at 35*F rise.

Even if the temperature rises by more than 50*F, the heater will continue to pump out a respectable 6.8GPM. Hence, regardless of the outside temperature, the Bosch Greentherm C 1050 will provide hot water to multiple applications at the same time. Finally, when the water flowrate is as high as churned out by the Bosch Greentherm C 1050, you have a reason to be worried about energy savings. Luckily, as suggested by its 96% thermal efficiency and 0.95energy factor, this heater won’t amp up your energy bills.


  • Bypass technology to provide consistent hot water
  • 7GPM flow rate
  • Multiple venting options – both for residential and commercial applications
  • Has 96% thermal efficiency


  • Though aluminum heat exchanger isn’t bad, Bosch would have been better had they used a steel heat exchanger

 Final Verdict 

Even with the aluminum heat exchanger, the maximum flow rate, thermal efficiency as well as multiple venting options make the Bosch Greentherm C 1050 the best gas tankless water heater.

Takagi T-KJr2-IN-NG Natural Gas Tankless Water Heater


Coming back down to the ground, we have decided to include a heater with a more reasonable price tag than the ones mentioned above.

Will it meet your needs? Let’s find out. Features Despite its low price – if there is one area where Takagi T-KJr2 rivals its high-priced counterparts, it has to be its max flow rate. For, it has a maximum flow rate of 6.6GPM, which means you can run multiple showers plus faucets on it at the same time.

Also, when a small heater is providing such a generous flow rate, temperature fluctuations might become the norm, since the heating area isn’t as big as it is in vast-sized heaters. Luckily, as suggested by the thermistors installed at both its inlet and outlet, Takagi T-KJr2 allows continuous monitoring of the temperature. It means that provided you keep the hot water demands in check, the temperature won’t fluctuate.

Finally, after so much good features, the law of averages states a shortcoming is next. That shortcoming lies in its venting procedure. Unlike the other best gas tankless water heaters, the Takagi T-KJr2 doesn’t allow any ordinary venting. Rather, it dictates you to get a 4’’ stainless steel vent to ensure its operation.


  • Huge flow rate for the price
  • Temperature fluctuations are very rare
  • Compact and lightweight
  • Has a 10 year heat exchanger warranty


  • Require expensive venting

 Final Verdict 

Consult the reviews of on demand gas water heaters, and you’ll be hard pressed to find a more cost-effective heater than Takagi T-KJr2.

Eccotemp FVI-12-NG High Capacity Gas Tankless Water Heater


If your hot water requirements are low – or you live in a one-washroom apartment, you may not need mammoth flowrates offered by the previous heaters. What you might need, however, is a cost-effective option from Eccotemp. Features If you want to check the confidence a manufacturer places in their product, check the warranty.

If the warranty is generous, the product, more often than not, will turn out to be good. Judging this heater on the same scale, and you’ll be astonished to find that it offers a lifetime warranty.

However, there’s a minor caveat: you will have to hire a licensed professional to install the heater to get the option of lifetime warranty. One thing you may want to note about this heater is the fact that it isn’t fully gas-operated. Put simply, while natural gas powers it, both the ignition, as well as the LED-temperature display, run on electricity.

Nonetheless, if you are worried, both these components only sniff electricity, meaning your energy bills won’t go up. Finally, to save the space around the heater from getting heat-up, Eccotemp has provided it with power venting. Thanks to the built-in exhaust fan, this venting will throw out all the gases from your home, and into the outside surroundings. Consequently, your home will remain cool and clean.


  • Very easy to install
  • Has power venting
  • Inexpensive for the flow rate it offers
  • A stainless steel vent comes in the package


  • Energy efficiency is depressingly low: just 79%

 Final Verdict 

AIf you want a gas heater which doesn’t turn your house into a den of harmful gases – while also delivering a respectable flow rate, your search ends with the Eccotemp FVI-12.

Rinnai RUC80iP Ultra Series Propane Tankless Water Heater


Judging by the number of reviews this heater has got, you’d know that it is relatively new on the market. However, judging by its features, you’d know that the Rinnai RUC80iP – like its predecessors, means business. Features Do you know what the most notable feature of this heater is> It is Wi-Fi ready.Thanks to this feature, it allows you to adjust its temperature from a tablet or smartphone.

What’s more, if you want to check whether your product is original or not, you can also register its product code to find the same. More importantly, if your spouse has gone to the washroom and has forgotten to turn the heater on, you don’t have to get up from the couch to turn it on. Rather, with the Rinnai RUC80iP, you can turn the heater on from your tablet.

Finally, ending our praise of the Wi-Fi technology, it also sends you periodic maintenance alerts, hence making sure your heater lasts longer than most. After surprising us with its Wi-Fi technology, this heater boasts yet another feature which most others can only dream of: a combo of high water flow rate and ultra-low emissions. Yes, despite churning out 8.0GPM, it has ultra-low NOx emissions, meaning it would keep your carbon footprint down.


  • Have Ultra-low NOx emissions
  • Has a 96% energy efficiency
  • Two venting options: Concentric and PVC
  • 8GPM Flow rate
  • Comes Wi-Fi ready


  • Cannot be installed indoors

 Final Verdict 

If you think you have the space to install your tankless heater outdoors – not that it would take much space since it is compact, the Rinnai RUC80iP is a must-have. 

Rheem RTGH-84XLN

Outdoor Natural Gas Condensing Tankless Water Heater Low Nox


If you have a large household and multiple members demanding hot water at the same time, the Rheem RTGH-84XLN deserves a favorable glance. Features Most of us are usually concerned with energy savings, and not water savings.

This heater, however, saves both. For, it gives you the option to decrease the water flow in the pipes until it reaches the desired set point. Consequently, you can save as much as 1,1100 Gallons of water per annum. Another notable feature of this heater is its low fixture capability.

While it has a maximum water flowrate of 8GPM – meaning it can provide hot water to multiple showers at the same time, this heater will start delivering hot water at 0.40GPM. That is, even when the water demand is low, this heater won’t let the temperature to fluctuate.

Also, while most Rheem heaters are already famous for their ease of installation, this one will help you in its service as well. Yes, when it’s time for maintenance, the Rheem RTGH-84XLN will start displaying warning codes on its LCD screen, hence forcing you to take notice.

Lastly, to make sure you have maximum ease while operating this heater, two features come into play, the first of which is the built-in electrical blower. It takes the gases from inside the heater to the outer surroundings, hence ridding your home from unnecessary heating. Second, it comes with a remote control, meaning you won’t have to walk to the heater to operate it.


  • Saves both water and energy
  • Is Compatible with low-flow fixtures
  • Displays periodic maintenance alerts on its screen
  • Comes with a remote control and built-in blower
  • Capable of operating at high altitudes


      • Not the most compact

     Final Verdict 

    If you ask me, this heater gets a four-and-a-half star rating from me. It isn’t perfect, but it isn’t far enough from being perfect either. What’s more, it might last decades before needing a replacement.


    Your search for the best gas tankless water heater ends here. In addition to reviewing the good points of the heaters under our consideration, we also compiled the bad ones from the gas tankless water heater reviews. Hence, depending on your needs – and the capabilities of the heaters, the onus is now on you to make a choice.

    Best Gas Tankless Water Heaters
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    Best Gas Tankless Water Heaters
    A guide to help you out choose one of the Best Gas Tankless Water Heaters.
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