There’s a good number of reasons why many people are switching to tankless water heaters nowadays. An endless supply of hot water, lower energy bills, and additional storage space are to name a few. There are several different types of tankless water heaters. Some factors, such as lack of electrical power or better availability of natural gas in your area, will dictate which would be more suitable for you. If you are not sure if you should choose an electric or gas tankless water heater, our comparison with pros and cons for each product below might be of help.
However, if you have already made a decision in favor of the natural gas type, you might find our tankless gas water heater reviews below useful in your search. When choosing these top 6 products we researched and reviewed all the best tankless gas water heater models in 2021. These models are the most popular this year, they have been showing the best results of performance, and they are sure to provide you good quality for the money.
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- Rinnai RL94iN
- Max flow rate: 9.4 GPM
- BTUs: 9,900 - 199,000
- Energy factor: 0.82
- Dimensions: 9.3 x 14 x 23
- Other: Energy Star, 12-Year Warranty on Heat Exchanger, 5 Year Parts, 1 Year Labor for Residential Installations, Digital Controller
- Rheem RTGH-95DVLN
- Max flow rate: 9.5 GPM
- BTUs: 199, 000
- Energy factor: 0.94
- Dimensions: 18.5 x 9.8 x 27.5
- Other: Self-diagnostic system, digital display, 5-year parts and 5-year heat exchange warranty
- Takagi T-KJr2-IN-NG
- Max flow rate: 6.6 GPM
- BTUs: 140,000
- Energy factor: 0.81-0.83
- Dimensions: 6.7 x 13.8 x 20.3
- Other: Energy Star, 10 year heat exchanger and 5 year parts warranty, Inlet, outlet thermistors
- Takagi T-H3-DV-N
- Max flow rate: 10 GPM
- BTUs: 199,000
- Energy factor: 0.95
- Dimensions: 11.2 x 17.8 x 24.9
- Other: Energy Star, Computerized safety features, 15-year limited heat exchanger, 5 yrs limited parts
- Rheem RTG-64DVLN
- Max flow rate: 6.4 GPM
- BTUs: 11,000 - 150,000
- Energy factor: 0.82
- Dimensions: 14 x 10 x 26
- Other: Energy Star, Low Nox Version, UMC-117 remote control and 10-Feet of thermostat wire is included, 5-year parts, 12-year heat exchange warranty
- Bosch 520 PN NG
- Max flow rate: 5.3 GPM
- BTUs: 117,000
- Energy factor: 0.78
- Dimensions: 10.5 x 18.5 x 36.8
- Other: Energy Star, Piezo ignition system, 3 - 15 Years warranty depending on application
- 1 Top 6 Tankless Gas Water Heaters
- 2 Takagi T-KJr2-IN-NG Tankless Natural Gas Water Heater
- 3 Rinnai RL94iN Natural Tankless Water Heater
- 4 Rheem RTGH-95DVLN Direct Vent Tankless Natural Gas Water Heater
- 5 Takagi T-H3-DV-N Natural Gas Indoor Tankless Water Heater
- 6 Rheem RTG-64DVLN Prestige
- 7 Bosch 520 PN NG Therm Tankless Water Heater
- 8 Electric or Gas Tankless Water Heater – Which to Choose?
- 9 Conclusion
Top 6 Tankless Gas Water Heaters
Takagi T-KJr2-IN-NG Tankless Natural Gas Water Heater
The top rated gas tankless water heater is the Takagi T-KJr2-IN-NG. Its comprehensive features and sleek design clearly distinguish it from its many competitors. This small unit is marketed as the smallest model in the Takagi line-up. This model also has a similar option with specs for outdoor use.
The capacity of this Takagi model should be suitable for an average sized household that has 2-3 bathrooms. It has the input of 140,000 BTUs per hour which in retrospect offers the performance of a 40-gallon tank water heater. Its maximum flow rate of 6.6 gallons per minute means that you can have simultaneously several applications in use.
With the weight of 33 pounds and measurements of 20 ¼ x 13 ¾ x 7 ¾ inches, this is not the smallest tankless water heater on the market. However, for the size, it offers a much larger water heating capacity compared to many other competitors.
Takagi T-KJr2-IN-NG can be mounted on a wall or placed under a sink, and you will need a 4-inch stainless steel venting line for the installation. We would recommend getting a professional for this, as proper installation will ensure that there’ll be no safety concerns in the future.
The efficiency for the T-KJr2-IN-NG is rated at 0.81-0.83. The possibility to considerably save on the electricity bills is what makes this model a hit among so many consumers. For easy maintenance, there are inlet and outlet thermistors for monitoring the temperature level.
Additionally, there are several safety features to ensure consistently safe operation of the unit. They include internal freeze protection system, air fuel ratio sensor, and a water and exhaust temperature safety control.
Rinnai RL94iN Natural Tankless Water Heater
The next best natural gas tankless water heater comes from the popular Rinnai brand. This Energy Star qualified RL94iN model provides a good range of features, quiet operation and consistent efficiency.
One of its advantages is the high water heating capacity which is rated at 9.4 gallons per minute at 30-degree rise. You can use this water heater for both residential and commercial needs. The high volume allows installation for up to 5 plumbing appliances.
The natural gas input is rated between 9,900 and 199,000 BTUs. A digital controller allows you to set the desired temperature. Moreover, an advanced feature of this natural gas tankless water heater is that you can set different temperatures for different appliances. So you can have two appliances working simultaneously and each will have its own water temperature.
The temperature range starts from 98 degrees to 140 degrees. If you will be using the unit for commercial installation, you will need to additionally purchase a commercial controller which will provide the water temperature range from 98 to 185 degrees.
For the installation, you will need to vent the unit to the outside using concentric venting system. As with any other gas tankless water heater, we would recommend getting a professional to help with the installation.
This model was launched in 2011 and ever since has been at the top of the market. It’s one of the pricier models, but with Rinnai RL94iN you can be sure that you are getting the best buy for the money. Its 12-year warranty on the heat exchanger, as well as 5 year on parts, backs up the quality of this product.
Rheem RTGH-95DVLN Direct Vent Tankless Natural Gas Water Heater
Rheem RTGH-95DVLN comes from the Prestige series of the brand and offers a top notch water heating solution. It runs on natural gas and can provide an endless supply of hot water to an average sized household.
This tankless natural gas water heater provides a highly efficient water heating solution. It uses condensing technology which works by using exhaust gasses to heat the incoming cold water. With 94% energy efficiency rating thanks to the stainless steel condensing heat exchanger design, this model is also Energy Star rated and certified by AHRI.
With 9.5 water flow rate, the RTGH-95DVLN is capable of handling high hot water demands. If you have even higher demand applications, you can connect this unit to a second one to get them operating as one. For this purpose, the package comes with an EZ-link cable.
The remote control panel and intelligent electronic controls provide easy use of the appliance, using which you can set the desired output water temperature. Using up and down buttons, you can set the temperature up to 120 degrees. The digital display shows the chosen settings and the maintenance codes generated by the self-diagnostic system.
Other benefits of this system include an environmentally friendly Low NOx burner, built-in electric blower, freeze protection, and the possibility of being linking in up to 20 unit manifold installations (optional MIC-185/MICS-180 manifold control assembly).
Takagi T-H3-DV-N Natural Gas Indoor Tankless Water Heater
One more Takagi highly rated tankless gas water heater is the T-H3-DV-N model. It offers the highest water heating capacity on our top 6 list, rated at 10 gallons per minute. In addition to being used as a water heating appliance, it can also be used with hydronic heating systems and radiant floor systems.
The high capacity of this model makes it suitable for up to 4 bathrooms or multiple uses of applications at the same time. Though if you live in a colder climate, it might be more suitable for a 3 bathroom house.
In addition to high capacity, T-H3-DV-N also has high efficiency. It offers ultra Low NOx condensing technology, complying with the regulations, and gas inputs of up to 199,000 BTUs.
To guarantee its quality and efficiency it comes with an Energy Star rating and a 15-year limited warranty on the heat exchanger and 5 years on parts if the unit is installed for residential use.
This tankless water heater is designed to be environmentally friendly due to the inclusion of PVC venting to its construction. So even though the unit is powered by natural gas, there’s no heated air coming out of the exhaust.
The main heat exchanger utilizes copper alloy, while the second one utilizes stainless steel that gives better corrosion resistance. You can link the model to multiple units: up to 4 without the use of a Multi-Unit Controller, or up to 20 if using the Multi-Unit Controller. To keep the water heater safe in operation it includes a freeze, surge, overheat protection, and also troubleshooting diagnostic codes.
Rheem RTG-64DVLN Prestige
Rheem RTG-64DVLN also provides an efficient and affordable solution to residential water heating. This natural gas powered unit was specifically designed for indoor use. It also meets the Ultra Low NOx regulations, making it safe for the environment.
The condensing heat exchanger that utilizes stainless steel provides 82% efficiency. For an improved efficiency, the device includes intelligent electronic controls. RTG-64DVLN is listed by AHRI which practices environmental stewardship which shows that this device really is efficient. Moreover, this product qualifies for federal tax credit.
At 35 degree rise, the model will output up to 6.5 gallons per minute which is its maximum water heating capacity. With this capacity, This Rheem model is ideal for 1-2 bathroom applications. If you have higher hot water demands, you have the option of connecting this unit to a second one. The package includes an EZ-link cable to connect them together. You can also manifold it to up 6/20 units depending on which manifold control assembly you’ll be using.
RTG-64DVLN uses a concentric venting system with a built-in condensate collector. To minimize the fluctuations of water temperature, there’s a hot programming feature.
To provide easy servicing, the model’s features include a self-diagnostic system. You can view the maintenance codes on the digital display, on which you also view your temperature settings. For safe operation, there’s additionally a freeze protection.
Bosch 520 PN NG Therm Tankless Water Heater
Bosch 520 PN NG is one more winning natural gas model in 2021. It also packs many interesting features, providing the best kind of user experience. It’s suitable for a whole house application. However, the 5.2 gallons per minute water heating capacity might be suitable for only 2 applications.
This energy efficient tankless gas water heater supports up to 117,000 BTUs, which is a quite high input for a product of this range. The 78% efficiency ensures that you can continuously save up on your energy bills.
This Bosch model runs on natural gas without any electricity required, not even for the ignition. It utilizes Piezo ignition system which works with the use of a small turbine inside the unit which utilizes the power given by the energy of the water flow and ignites the burner. So with just a push of a button, the system ignites.
A modulating gas valve maintains a steady water temperature level, even if the water flow fluctuates. The 520 PN NG includes a galvanized B vent for the venting of this water heating system.
Electric or Gas Tankless Water Heater – Which to Choose?
There are different factors that might dictate which type would be more suitable for your household. For example, if natural gas was more available in your area or if there’s lack of electrical power, then you would probably choose a tankless gas model. On the other hand, electricity is cheaper in most areas, so you might opt for the electrical type. Below we’ve broken down some factors that could influence your choice, and compared the two types against each other.
- Price. Typically, electric models are more affordable. Most of the products you will find in the $500-700 price range. There are pricier models, but you can easily find a very reliable water heater in that range. Gas powered models, on the other hand, are mostly in the $1000-1200 price range. The lower priced options will generally offer much lower water heating capacity and might offer a lower quality of performance. If the product is offered from a more reputable brand, the price of a gas-fueled unit might even be higher.
- Installation Ease and Cost. As for installation, the electric option also wins over the gas type. Electric tankless units are generally much cheaper to install and the whole process is much simpler. It just requires an adequate electrical connection. In some situations, if the user has some basic electrical knowledge, he might be to install the unit without professional help. Gas tankless devices require more complicated and expensive installation. You will need a professional to carry out the venting requirements, which will include confirming venting options, gas line size, and fresh air supply. The venting requirement also decreases the gas unit’s installation options.
- Flow rates. Here the gas option has the advantage as it generally offers higher flow rates. On an average model, you will have about 8 gallons per minute flow rates. On some models, you can even have up to 10 GPM if used in warm climates. Electric models have an average of about 3-4 GPMs per minute in warm climates. Lower in colder climates. On some of the more advanced models, they offer up to 8 GPM in warm climates.
- Operating cost. Natural gas might be slightly cheaper but it is projected to rise in the future, while electricity costs are more stable and its price will probably not rise dramatically. Since tankless units are a long term investment that can last as long as 20 years, it makes electric models cheaper to operate.
- Environmental impact. Again, an electric option has the advantage. Both types have a small size which leaves a small environmental footprint with lesser manufacturing and ultimate disposal. However, unlike the gas type, electric tankless units don’t have any greenhouse gas emissions. Gas water heaters also increase reliance on fossil fuels.
- Maintenance. While electric type requires no regular maintenance, the gas units require it to be performed annually.
Going tankless is a good way to save up on energy bills in the future. If you have decided that gas fueled model would be more suitable for your household, then in this article we have presented the best tankless gas water heater models that have been the most popular in 2021. They are known to show consistent performance and have been proven to give reliable quality. Reading the tankless gas water heater reviews should help you understand which model would make a better fit for the requirements of your home. However, if the gas and electric options comparison have persuaded you to opt for an electric tankless unit, you can find a best tankless electric water heater by following the link.