Best-Selling Tankless Gas Water Heater Reviews 2020: Buying Guide, Reviews & Useful Tips

Best-Selling Tankless Gas Water Heater Reviews 2020: Buying Guide, Reviews & Useful Tips

One of the most frequently used heating machines powered by natural gas is tankless gas water heater. The best part is that the using cost is very low. There are a number of gas water heaters available in the market such as indoor type, whole home type, portable, outdoor type and many others, but you need to choose the one that fits to all your needs. While choosing a tankless gas water heater, you should consider your actual requirements.

In this post, we will list down some of the best gas water heaters and provide you with some suggestions needed to choose the best one for your house.Best-Selling Tankless Gas Water Heaters

Best Tankless Gas Water Heaters Available in the Market

Some of the best models of gas water heaters without a tank available in the market are listed alongside with their features, pros and cons. This will help you making a good buying decision. Go through the brief tankless gas water heater reviews and know more about them.

1. Rinnai RUC98iN Ultra Natural Gas Tankless Water Heater

Rinnai is one of the best brands when it comes to natural gas water heater. This model by Rinnai is one of the hot-selling type in 2019. It can be installed indoor and comes with twin pipe installation giving you more choices for venting.

Top Features

  • Large Flow Rate: It gives a high flow rate of 9.8 gallons per minute and can easily support a large house with 3-4 bathrooms and multiple kitchen faucets simultaneously. You can even use it for the commercial purpose when you cascade few of them together.
  • High Temperature Range: The maximum temperature reaches to 140 Fahrenheit while the minimum is 98 Fahrenheit. You can adjust the temperature depending on your hot water requirement. For commercial purposes, the temperature can be raised to 185 Fahrenheit using a commercial remote.
  • Highly Energy Efficient: It requires power ranging from 15200 to 199000 BTU per hour. The efficiency reaches up to 95% which means that energy is seldom wasted during the unused period. It can save your heating cost extensively.


  • You are offered with two venting options – concentric PVC or twin pipe.
  • It just requires 2 watts to keep the machine up and running.
  • The hot water starts flowing within 20 seconds.
  • It offers 5-year warranty on heating parts.
  • It can used for commercial purpose if you cascade a few of them together.
  • It works very quietly unlike other gas water heaters.


  • It requires professional aid for installation.

2. Rheem RTG-95XLN Low NOx Outdoor Tankless Natural Gas Water Heater

It is an outdoor tankless gas water heater. This means that it doesn’t require any venting kit to be installed. Moreover, it is available in both propane and natural gas variant.

Top Features

  • Large Flow Rate: It delivers up to 9.5 gallons per minute flow rate which means that it can serve a complete house having multiple bathrooms and kitchen faucets. You can even use it for commercial purposes by cascading many of them together.
  • High Energy Rating: The energy efficiency of this unit can reach up to 94% making it one of the most efficient gas tankless water heaters. It proves to be environment-friendly as it emits less carbon dioxide.
  • Remote Control Available: The machine uses EcoNet smart home technology and this enables you to control the machine remotely through an app. As it’s an outdoor machine, you can adjust the gas power and water temperature while sitting at comfort of home.


  • The stainless-steel heat exchanger provides you with option to connect both vents when the water demand turn high.
  • It is available in both propane and natural gas variant.
  • It offers a standard 10 years warranty on all heating parts.
  • It is available with remote control.
  • As it is an outdoor machine, no ventilation is required.
  • It supports multiple bathrooms and kitchen faucets simultaneously.
  • The hot water supply is constant.


  • It requires professional assistance for installation.

3. Takagi T-KJr2-OS-NG Outdoor Natural Gas Tankless Water Heater

It is one of the natural gas tankless water heater model that is best suited for a small-sized or mid-sized family.

Top Features

  • Decent Flow Rate: It is suitable for mid-sized or small-sized houses delivering a flow rate of 6.6 gallons per minute. It can support 1-2 bathrooms along with kitchen faucets simultaneously.
  • Stylish & Compact Design: The T-KJ2 series is light in weight and compact in design in whole line of Takagi tankless water heaters. It saves a large area, no matter whether the installation is indoor or outdoor.
  • 150 Fahrenheit Temperature: The maximum temperature for this unit reaches to 150 Fahrenheit while the power needed is 140000 BTU per hour. It delivers the energy efficiency of around 83%, saving some of your heating cost.


  • It is compact in shape.
  • Available in both propane and natural gas variant.
  • It delivers constant hot water supply.
  • You can install it easily.
  • It supports two bathrooms simultaneously.
  • It demands minimal maintenance.


  • It makes noise while working.
  • Professional assistance is required for installation.

4. Naiven NPE-240-A Tankless Gas Water Heater

Naivan NPE-A series is one of the best tankless water heaters that are also considered as the water heater of future. Its technology has been patented and the heater is crafted to deliver optimal performance.

Top Features

  • Built-in Buffer Tank & Recirculation Pump: This natural gas tankless water heater is designed with ComforFlow technology. It has an inbuilt buffer tank and recirculation pump to reduce the Coldwater sandwich, saving your water bills by reducing the time of getting the hot water. It needs just one second to supply you with hot water.
  • External Interface Installed: Its external interface is well equipped to show the water temperature and error codes. You can turn the button on and off to adjust the temperature quickly.
  • Condensing Stainless Steel Heat Exchanger: It is designed with patented condensing technology. The dual stainless-steel heat exchangers recover the extra heat, reducing the energy consumption and emission of carbon dioxide. It also keeps the exhausted temperature fairly low.


  • Short waiting time for hot water.
  • It is pretty powerful.
  • It uses intelligent preheating technology to make your life easier.
  • It is good at keeping temperature stable.
  • It can adjust the water temperature quickly.


  • It makes a little noise while working.
  • You have to buy its remote control separately.

5. Noritz NRC661-DV-NG Tankless Hot Water Heater

This unit by Noritz offers average flow rate reaching up to 6.5 gallons per minute and is suited for mid-sized houses.

Top Features

  • Average Flow Rate: As compared to other gas tankless water heaters at this range, the flow rate is relatively lower, but it can still support hot water needs of two bathrooms and kitchen faucets together. If you use it in colder areas, then it can only support a single bathroom and kitchen faucet.
  • Dual Heat Exchangers: It has two heat exchangers made from different material set – one from stainless-steel and other one from copper. Both of them last for longer period of time and are corrosion resistance. It also comes pre-installed with freeze protection devices.
  • Highly Energy Efficient: The gas consumption is between 15000 to 120000 BTU per hour while the thermal efficiency reaches to 93%, helping you save a large amount of money.


  • It is compact in design.
  • It works quietly.
  • It can be vented with Schedule 40 PVC pipe and fitting.
  • It has got a low NOx design resulting in less carbon dioxide emission.
  • It comes with freeze protection system.


  • Requires professional assistance for installation.
  • It results in cold water sandwich.

The Best Natural Gas Condensing Water Heaters

Because of the individual working principle of the natural gas tankless hot water heater, most of the leading brands make their heaters as condensing types, thereby reducing the energy consumption and greenhouse gases emission.

Some of the best natural gas condensing tankless water heaters we would like to recommend you are as follows:

1. Naiven NPE-240-A Tankless Gas Water Heater

Most of the Naiven tankless water heaters are made with condensing technology as it helps to reduce the emission of greenhouse gases and energy consumption too by recovering the extra heat that is lost in non-condensing water heaters.

There are a number of Naiven natural gas water heaters to choose from. You can select them according to your requirements and budget.

2. Noritz NRC661-DV-NG Tankless Hot Water Heater

It is another awesome condensing gas tankless water heater that is worth recommending. It has got two heat exchangers – one made from stainless steel while the other one made from copper. The NOx design makes its more efficient in saving the energy and heating costs while reducing greenhouse gases emission.

What is a Tankless Gas Water Heater?

A tankless natural gas water heater is a heating machine that is majorly powered by natural gas. It is capable of heating water in few minutes and supports the constant hot water supply that doesn’t happen in case of tank-based water heaters.

When you have installed this heater at your place, you never have to worry about running out of hot water. Moreover, it is energy efficient and gives you more savings on your energy bills and also reduces your heating costs to a large extent.

Why you should choose Tankless Water Heaters?

Some of the reasons to go with tankless water heaters over tank-based heaters are as follows:

1. They are Environment Friendly

As compared to petroleum-based fuels, the tankless type gas water heaters are much cleaner and emit 45% less carbon dioxide as compared to other non-gas water heaters.

2. More Efficient

As compared to the non-gas tankless water heaters like electric ones, the gas water heaters are 3 times more efficient and makes use of up to 90% of usable energy. The efficiency can reach up to 95% in some cases.

3. More Economical

The actual cost of tankless gas water heater is low as compared to others and they are more powerful too. A gas-powered tankless hot water heater is capable of saving 30% of your heating bills, according to a professional survey.

4. More Reliable

The natural gas gets transferred and used through the underground pipelines in case of gas tankless instant hot water heaters. This gas can be used for multiple applications simultaneously. Therefore, it is safe and more reliable.

What are the Different Types of Tankless Gas Water Heaters?

Having different installation spots and applications, the tankless gas water heater types are as follows – outdoor type, indoor type, portable type and whole home type. Here, we provide you with basic definition for each type and what is the fundamental difference between each type along with best use case for each type.

1. Indoor Gas Tankless Water Heater

The indoor gas tankless water heater is heating machine which can be installed indoor (either in bathroom or kitchen or under the sink). The major key to indoor heater is ventilation. It demands ventilation kits to be installed so that the gas emitted during the process is directly thrown out of the house.

If it is installed near point of use, then it will take only few seconds for the hot water to flow and the primary waiting time will get reduced to a large extent. You can check some of the best reviews of indoor water heaters to know more.

2. Outdoor Gas Tankless Water Heater

As the name suggests, the outdoor tankless water heater is installed outside the home. In order to reduce the waiting time for hot water, it is often installed behind the wall of bathroom or kitchen. It requires no ventilation as the gases emitted are directly thrown out. You need to ensure that it stays protected during the bad weather conditions.

There are a number of things to be considered while installing outdoor gas tankless water heaters and this is why we have created reviews for it. You can check them to learn more.

3. Whole House Tankless Gas Water Heaters

Hot water is needed in a house while taking bath, doing the laundries or washing the hands, especially in cold weather season. Thus, you need to install a whole house tankless gas water heater to meet the needs of your home.

The flow rate required is relatively higher as it will support multiple bathrooms and kitchen faucets simultaneously. To get some more information, go through the whole house tankless gas water heater reviews that we have collected from different sources and people.

4. Portable Tankless Gas Water Heaters

The portable tankless gas water heaters are small tankless gas water heaters that can be carried while travel or are installed in a recreation vehicle (RV). They are best suited for camping or travel purpose.

The flow rate is quite low in these type of water heaters as they are designed light in weight and compact in shape. Also, they are available at lower price as compared to other types. You can read the reviews on portable gas tankless water heaters directly on Amazon from here.

Best Selling Tankless Gas Water Heaters

  • Most Powerful One – Rinnai RUC98iN Tankless Water Heater
  • The Lightest One – Takagi T-KJr2-OS-NG Tankless Water Heater
  • The Most Energy Efficient One – Noritz NRC661-DV-NG Tankless Water Heater

Electric vs. Gas Tankless Water Heater

Electricity and gas are the two major power sources of tankless water heater system and many people get confused while making a buying decision between the two. Below is the comparison between the two:

Electric Tankless Water Heaters Gas Tankless Water Heaters
Pros ·         Do not emit carbon dioxide directly.

·         More affordable.

·         Don’t need ventilation.

·         Not affected by high altitude.

·         It is more powerful and support multiple bathrooms and faucets.

·         Lower cost than electricity.

·         Much safer to use.

·         Can easily heat water in cold climate.

Cons ·         It is less powerful and requires multiple units to support equal power as the gas type.

·         It requires more maintenance.

·         It is more expensive on heating bills and costs.

·         More expensive on price as compared to electric type.

·         Emit Carbon dioxide directly through vents.

·         It requires ventilation.

How to choose the Best Tankless Gas Water Heater – Buying Guide

There are a number of brands and models of tankless gas water heaters available in the market that most of us get confused while making a buying decision. But we need to think wisely and consider several factors before buying the gas tankless water heater from the market. Here are different factors that will help you choose the best tankless gas heater according to your requirements.

1. Flow Rate

If you need water heaters for camping or travelling purpose, you will require lesser flow rate of up to 2-3 gallons per minute. The portable or point of use type water heaters will do it for you. But when you are looking to install the water heater in your entire house having 3-4 bathrooms and multiple faucets, you will require a heater with higher flow rate of up to 10gpm. You know what is required for you house.  So, take the decision wisely.

2. Ventilation

As natural gas will be the major power source, the gas tankless water heater will require ventilation kits to emit the greenhouse gases outside your home. The universal ventilation kits are not suitable for each machine sometimes. You need additional PVC pipes or special ventilation method. Also, you have to look weather you will be going with indoor or outdoor installation. No ventilation kits are required in outdoor installation.

3. Size

The size of tankless gas water heater is another factor to consider while making your decision of buying. If you have a big house and space is not the issue, heater of nay size will do. But if you have a small house, you will require tankless water heater that is compact in design and shape and can easily adjust in any area without consuming too much space.

4. Energy Efficiency

How efficient the natural gas tankless water heater is? This is the question you must ask yourself before buying one for your house to save on heating bill. The gas tankless water heaters can reach up to 95% thermal efficiency while most of them can deliver an efficiency ranging from 60-80%.

5. Hot Water Waiting Time

Obviously, you will have to look which water heater can deliver lowest waiting time to save the cold water and thereby saving the water bills. The distance of installation will mater in this case, but the ability of machine to produce hot water quickly will also matter.


  • Venting kits are must to be installed for indoor installations.
  • You should not put inflammable things on water heating machine.
  • The heater should be installed keeping a safe distance in mind from water and other devices.
  • You should turn off the gas valve every time you stop using it.
  • Always read the instructions carefully before using.
  • Take help of professionals to install the machine.

Tankless Gas Water Heater Prices

The tankless gas water heaters are higher in price as compared to other types. Most of them are available around $1000 and there are installation costs as well. The using costs can be extremely low while the maintenance costs are negligible.

You can save a huge money on heating and water bills after installing the gas water heaters. The initial cost of installation and purchase is high, but you will enjoy the reduced electricity bills and water bills later after the installation.

Best Tankless Water Heaters Best Type
Rinnai RUC98iN Tankless Water Heater Most Powerful One
Takagi T-KJr2-OS-NG Tankless Water Heater The Lightest One
Noritz NRC661-DV-NG Tankless Water Heater Most Energy Efficient One

Natural gas tankless hot water heaters are becoming more powerful nowadays. Most of the leading brands like Naiven, Rheem, Takagi and Noritz ate doing their best to improve the performance of the gas type water heaters without a tank.

If you are looking to buy gas tankless water heaters, then this guide would come handy for you. You can check some of the best water heaters running on gas directly from Amazon.

Leave a Comment