Best Natural Gas Tankless Water Heater in 2018 – Reviews and Buyer’s Guide

Natural gas tankless water heaters have nowadays become more popular as the demand for efficient home appliances increases. Various natural gas tankless water heater brands manufactured by different companies are currently competing in the market. But for the best result, choosing the Best Natural Gas Tankless Water Heater is the most important part.

Natural gas tankless heaters usually deliver more consistent temperatures as well as a high volume of water while also managing to use up less energy as compared to the “tank” water heaters. Unlike other conventional units, these heaters are only active when needed thus saving an average of 45% on the consumer’s energy bills.

The best natural gas tankless heater models also provide hot water at once instead of having to pre-heat and store the water. This means that the water will not run out and it can be used concurrently in various areas of the house.


Top Five Best Natural Gas Tankless Water Heater in 2018 [Comparison Chart]

Natural gas tankless heaters are popular since they give the precise amount of hot water that you need. This type of heaters can save your money since you do not end up heating several gallons which just sit in the tank, waiting to be used.

An efficient gas hot water heater will save you considerable amounts of cash. However, the market is home to a wide range of hot water heater models and it’s important to choose the heater that best suits the family’s hot water needs.

Here are the top 5 natural gas water heaters:

#1 Rheem RTGH-95DVLN 9.5 GPM Indoor Natural Gas Tankless Water Heater

Rheem RTGH 95DVLN ReviewRheem RTGH-95DVLN 9.5 is a top-class water heating solution which runs on natural gas and also provides an unlimited supply of hot water to your whole family.

It’s very simple to use natural gas heater which comes with the remote control panel that’s designed for setting the output’s water temperature. You might also use the heater to display the fault codes.

With the up and down arrow buttons, you might change the default temperature setting which is set on 110 degrees F to 120 degrees F. The heater comes with the stainless steel condensing heat exchanger and it’s 94% efficient. The Rheem RTGH-95DVLN is also an ENERGY STAR rated natural gas tankless heater.

Operating at around 199,000BTUs, Rheem RTGH-95DVLN 9.5 is a high-performance natural gas tankless heater.

The Rheem heater contains the two-pipe direct vent system that connects up to 5 feet of 2-inch PVC pipe or 35 ft. of 3-inch PVC pipe.

Main Features:

  • The stainless steel condensing heat exchanger on the heater makes it 94% energy efficient
  • Rheem RTGH-95DVLN 9.5 has increased safety and efficiency with Intelligent electronic controls
  • The heater also has a two-pipe direct vent system which connects up to the 5 ft. of two-Inch PVC Pipe or the 38 ft. of three-Inch PVC Pipe
  • It also has a Low Nox model
  • The installation and servicing has also been made easy using the self-diagnostic system
  • The maintenance codes and temperature setting are easily viewable via the digital display
  • The natural gas tankless heater comes with the built-in electric blower
  • The Rheem RTGH-95DVLN 9.5 is equipped with the Guardian to overheat Film Wrap
  • The heater comes with the EZ link cable to connect 2 tankless units
  • The 120V power cord has also been included in the indoor models

Check out the complete list of Rheem Tankless Water Heater Reviews Now

#2 RINNAI RL94IN 9.4 GPM Natural Gas Tankless Water Heater

Rinnai RL94iN ReviewExperience the never-ending supply of hot water and a sculpted sleek water heater design using the Rinnai RL94iN Heater. Whether you’re building a spacious home or you are just remodeling the older home, it can be used in pairs, individually or in banks of 3 or more so as to supply your entire homes hot water needs.

The Rinnai RL94iN can be placed in almost any room, vent to the outside directors and has an integrated condensate collector. The natural gas tankless heater also requires no additional venting and it can be installed even in a recessed enclosure where it’s painted or textured so as to match with your home’s exterior home for a clean and inconspicuous appearance.

This Tankless Water Heater has also contained the commercial-grade heat exchanger for maximum durability. With this best gas hot water heater, homeowners will get the reliability of the commercial-grade construction as well as an industry-leading warranty of 12 years.

Main Features:

  • Sleek and modern design with a sculpted cover and silver finish
  • Significant space savings as compared to the tank-style heaters
  • Long-lasting design as well as the reduced risk of flooding
  • The heater also has the included isolation valves that ensure serviceable and professional installations
  • Applicable for both commercial and residential applications
  • Temperature range with standard MC-91 controller (included): 98F to 140F
  • The heater has Digital temperature control, troubleshooting and monitoring features.
  • The heater has an EZConnect feature for connecting two or more units. Three or more units can also be manifold using the MSA control board
  • The heater has a Residential Warranty of 12-year heat exchanger /1-year labour/5-year parts
  • The Rinnai RL94iN has a commercial Warranty of 1-year labour/5-year heat exchanger and parts

Check out the complete list of Rinnai Tankless Water Heater Reviews Now

#3 Rheem RTG-64XLN 6.4 GPM Low NOx Outdoor Natural Gas Tankless Water Heater

Rheem RTG-64XLN 6.4 GPM Low NOx Outdoor Natural Gas Tankless Water Heater ReviewRheem RTG is a well-known brand that’s popular worldwide for its eco-friendly, innovative, efficient and budget-friendly indoor and outdoor water heating solution.

People who need hot water instantly without compromising on the energy consumption and the utility bill must have this amazingly efficient tankless water heater.

The Rheem RTG-64XLN’s output is around 6.4 Gallons Per Min and it’s low on the NOx emissions. You can get hot water easily for two bathrooms. In addition, you can use it from approximately 10 feet distance and also through remote control.

The fact that Rheem RTG is an outdoor heater which runs on natural gas simply proves that there shall be no safety risks that are involved when using it. This is a very reliable outdoor tankless water heater.

The fact that Rheem RTG is an outdoor heater which runs on natural gas simply proves that there shall be no safety risks that are involved when using it. It is one of the most reliable outdoor natural gas tankless water heater.

Main Features:

  • Digital displays on thermostat normally show temperature setting and error/ maintenance codes
  • The Rheem RTG has a built-in electric blower for forcing exhaust gas to the outside
  • The Electronic ignition is designed to increase efficiency
  • Supplied with the 120-volt power cord
  • Industry best of 0.26 GPM minimum flow rates and 0.40 GPM min. activation flow rates
  • Suitable for Outdoor use
  • Provides a minimum of 6.4 gallons per min water at 35 Degrees Rise
  • THE UMC-117 remote control has been included
  • Up to 10-Ft of a thermostat wire has been included
  • Needs gas input of between 11,000 to 150,000 BTU per hour
  • The heater features a Low Nox Version

Check out the complete list of Rheem Tankless Water Heater Reviews Now

#4 BOSCH 520 HN NG Therm Natural Gas Tankless Water Heater

Bosch 520 PN Therm Natural Gas Tankless Water Heater ReviewBosch is a well-known natural gas tankless heater brands which come up with a series of water heaters from time to time.

The Bosch Therm 520 HN NG is one such popular tankless water heater brand which was introduced into the market in 2011. The Bosch Therm 520 HN has the pilot light and also offers a Piezo push-button ignition system.

The natural gas tankless heater also utilizes the modulating gas valve so as to ensure a constant temperature at different flow rates.

The Bosch Therm 520 HN NG is the perfect tankless heater for smaller households and families that only use less than two hot water appliances at a time.

Main Features:

  • The Bosch Therm 520 PN has a Piezo ignition system which requires no electrical connections
  • It has a 78 percent thermal efficiency
  • The heater has a 117,000 BTU maximum input
  • The Bosch Therm 520 PN has a 5.3 gallons/minute capacity at 35 degrees F rise
  • It provides endless hot water for a single application at a time
  • It has a minimum activation flow rate of around 0.5 gallons/minute
  • The natural gas tankless heater also has high to low temperatures control
  • It has vents with the galvanized B vent
  • The Bosch Therm 520 PN has been built for serviceability and durability with 15-year warranty
  • The heater is available in LP and NG models

Check out the complete list of Bosch Tankless Water Heater Reviews Now

#5 TAKAGI T-KJR2-OS-NG Outdoor Natural Gas Tankless Water Heater

Takagi T-KJR2-OS-NG ReviewTakagi T-KJr2-OS-NG is Released in 2010, This outdoor Tankless Water Heater is one of the smallest tankless heaters in Takagi’s tankless line. This is small yet powerful unit might meet all hot-water needs of a small home or apartment having one or two bathrooms.

The Takagi T-KJr2-OS-NG Outdoor Tankless Water Heater is designed to practically do anything that a 40-gallon tank-type heater can do. Furthermore, the compact and wall mounted T-KJr supports the radiant floor or hydronic baseboard heating applications. It also provides hot water to plumbing fixtures as well as appliances.

The Takagi T-KJr2-OS-NG is environmentally friendly and cost-efficient.

It can also be converted into a direct-vent heater by using the optional TV10 conversions kit for installation in the garage.

Main Features:

  • Capacity: 1 to 2 Bathrooms
  • Flow Rate: Maximum of 6.6 GPM
  • Gas Inputs of between 19,500- 140,000 BTU every hour
  • Energy Factor Rating of 0.82
  • Inlet Gas Pressure of a Minimum of 5.0″ W.C. and a Maximum of 10.5″ W.C.
  • Dimensions of 20.3″ H by 13.8″ W by 6.7″ D
  • The Takagi T-KJr2-OS-NG has direct Vent Capability
  • The Takagi T-KJr2-OS-NG also has an electric Ignition

Check out the complete list of Takagi Tankless Water Heater Reviews Now

How To Choose a Best Natural Gas Tankless Water Heater

A natural gas tankless heater can just be the second largest energy user system in your home, after the heating and cooling system.

As a result, it is important to make wise choices when you’re replacing an existing natural gas heater or when purchasing a new gas hot water heater.

Below are the factors to consider when choosing the best natural gas tankless water heater for your home:

Size and CapacityCompatibilityEfficiencyCostsYour hot water needs
The best way of determining the size of the natural gas heater that you want is its “first-hour rating” or the “recovery rate.” This is simply the maximum amount of the hot water that can actually be heated and then supplied within one hour starting with cold water. The first-hour ratings of natural gas heaters normally range from 41 to more than 131.

Generally, natural gas heaters have a higher first-hour recovery rate than the electric water heaters that have the same storage capacity. As a result, when you buy a natural gas tankless heater, you should take its size and capacity into consideration so as to get the best heater for your entire home needs. Natural gas storage heaters range in size from 20-80 gallons of capacity.

You should check to see whether your home has an access to the natural gas lines before purchasing the natural gas-fuelled heaters. Even if natural gas is available in your home area, it might be quite expensive to add the gas line to your home. Natural gas heaters also have to be installed in locations which can provide proper ventilation to the outside.

As a result, before you head to the market to buy a new natural gas tankless heater, you should always think about its compatibility with your home.

The energy efficiency rating of a natural gas heater is normally stated in terms of its EF (energy factor). The EF refers to the ratio of energy delivered as hot water when compared with the total energy that is used by the heater over a 24-hour period. The ratings take the efficiency of the source of energy into consideration that heats the water, the heater’s standby energy losses, as well as the energy lost when the heater cycles on and off. The higher the energy factor, the more energy-efficient the gas hot water heater is.
In order to determine the actual costs of using a natural gas water heater, you should always look at both the buying price of the water heater and its total lifetime operating costs. In most parts places, a natural gas heater can operate for around half the cost of an electric heater although the natural gas heater might cost a little more.

Similarly, a natural gas heater with higher efficiency ratings might cost more than a natural gas heater having a lower E F. However, you can save hundreds of dollars over the heater’s lifetime thanks to its lower operating costs.

When buying a natural gas tankless heater, you should always take a clean look at the hot water needs of your home. The “First Hour Rating” (FHR) tell you the amount of hot water that a heater can provide in every hour. The First Hour Rating should match the amount of water which your household requires when you use most hot water every day.

Benefits Of a Natural Gas Tankless Heater

In case the idea of constantly heating water in a tank sitting in the basement sounds wasteful and inefficient to you, then a natural gas water heater might be the right option for you.

The best natural gas water heaters have always been full of promises. By heating the water only when you require it, the suitcase-sized water heaters could potentially save the homeowners a lot of energy as well as storage space.

In addition, the endless hot water supplies mean no more cold showers in your home. Here are the benefits of a natural gas tankless heater:

  • Natural Gas is Green: Natural gas is cleaner than the petroleum-based fuels. Natural gas emits fewer chemicals that associated with smog, greenhouse emissions and acid rain. The average natural gas tankless heater home emits 46 percent less carbon than the non-gas counterpart. Replacing non-gas tankless heater with the natural gas tankless heater prevents around 3,000 pounds of carbon (IV) dioxide from entering into the atmosphere each year
  • Natural Gas is Efficient: Natural gas reaches the home directly at more than 3 times the efficiency of the non-gas energy. While natural gas tankless heaters provide up to 90 percent usable energy, up to 78 percent of non-gas’ o energy is already wasted by the time it’s delivered to the home. As a result, the natural gas tankless heaters are more efficient to use.
  • Natural Gas is Economical: Natural gas tankless heaters cost up to half the cost to operate as compared to the non-gas counterparts. Homes with the natural gas tankless heaters save an estimated 25 percent on energy costs each month.
  • Natural Gas tankless heaters are reliable: Natural gas is normally delivered to your home through underground pipelines and provides nearly 100 percent reliable services. Homes with natural gas tankless heaters can still use hot water and even cook even when the power goes out.


There are several brands of natural gas heaters to choose from and each brand is slightly different from one another. Some brands specialize in providing the environment-friendly technology while other brands put their main focus on power and efficiency. You should, therefore, be sure that you find the right model which suits all of the needs of the consumer, based on size, design, preference and price.

However, you should try not to make the decisions solely based on how much money will be deprived of the pocket. When purchasing the best natural gas heater, you should make sure that it will be of high quality and it’s also able to last for many years so that you will not have to worry about the heater for at least one decade or so.

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