9 Best Tankless Gas Water Heaters (2021) | Tankless Reviews

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The shortage of warm water supply during chilly winters is the worst nightmare for all. From burning woods for heating water to using home installed water heating units man has tried different possible means to fulfill his warm water necessity. Lately, with new advancements in science and technology energy-efficient, tankless water heaters were designed and have become immensely popular. Installing the best tankless gas water heater at home will provide for your whole family’s water need in no time.


To make sure you don’t get lost in products jumble we have picked the most efficient and affordable product options for you. Internet is loaded with a variety of product options, finding out the best one among them will require a lot of your time and effort. You can go through product details and use the link for direct purchase.


  Best tankless gas water heater

What benefit does a gas water heater offer? This question might arise in your mind. There are many reasons why buying a tankless gas water heater can be economical for you. Natural gas is cheaper than electric power so in long run less running cost. Tankless water heaters have a sleek design that occupies little to no space and it is best for people with small apartments.


Never run short of warm water supply. Yes, you read right tankless water heater supplies warm water continuously unlike their tank water heating counterparts. Although you will need to spend a hefty amount of money for purchasing and installing this unit with its durability in consideration this will be a perfect investment.


The list of best products we picked is next will all important features explained.


Rinnai V65IN Tankless Water Heater, Large, V65iN-Natural Gas/6.5 GPM

Rinnai tankless water heater is our premium pick product and has a 6.5 gallon per minute flow rate which means it is a great product for big family’s. Multiple faucets can be used at once with less reduction in flow rate. Tankless water heaters heat water on demand so the flow rate is affected if multiple faucets are turned on simultaneously. This unit has a mobile leak and scale detection app which saves your property from any possible damage caused by water overflow.



Individual parts can be replaced instead of the whole unit

20 years life expectancy

WiFi monitoring feature

Less carbon dioxide emissions



Requires professional installation


Key features :

Space-saving design:

This unit requires indoor installation but you don’t need to worry about a shortage of space. The unit is about the size of a small suitcase. This unit can be installed in any corner of your house even in nontraditional spaces like the attic or closet.

Energy-efficient :

You won’t need to worry about your bills after installing this unit. With the low level of carbon dioxide emissions and less energy use, this system will serve you for about 20 years which is a much longer duration compared to the tank water heating systems.

Sustainable :

Some products cost a lot for maintenance and this affects the budget and makes them a poor purchase. Rinnai water heating system is replicable so you can replace individual parts without having to buy a whole unit.

Leak detection :

A mobile app is used for detecting water leakage or scale build-up. The wifi monitoring feature keeps the unit connected to your mobile app and in case of any leakage water supply to the unit is automatically shut off this saves your property from any possible damage.


Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater, GRAY

Rheem tankless water heater has a compact design specially designed for residential use. This unit is 99.8 percent energy-efficient. No energy wastage makes this product a must-have. Rheem manufacturers have 100 years of experience and this makes their stand. Our editor’s choice product has a digital temperature display so you can adjust the temperature according to your needs.



Thermostat controlled display

Easy replacement

99.8 percent energy efficiency

Water-saving showerhead



Sufficient for small usage


Key features :

DIY installation :

The complete package includes adapters and compression water connections so a buyer can easily install the unit himself without any need for seeking professional help. DIY installation saves the expensive cost for professional help.

Highly energy efficient :

This system has 99.8 percent energy efficiency which means almost all energy is used for heating water and none gets wasted. This high energy efficiency feature saves your energy cost and makes the unit affordable for you.

Adjustable thermostat control:

A digital thermostat with the led display is present in front of this unit. This thermostat is used for adjusting water temperature according to the requirement. The temperature is adjusted in increments of one degree Fahrenheit.

Water-saving showerhead :

The showerhead has only a 1.5 gallon per minute flow rate which saves water drainage. This flow rate is enough for small usage but if you have a big family this unit will not be enough for you.



Tankless Water Heater, GASLAND Outdoors BE158 1.58GPM 6L Outdoor Portable Gas Water Heater, Propane Water Heater, Overheating Protection, Easy to Install, Use for RV Cabin Barn Camping Boat, White

If you are planning to travel during winter, a portable water heater is a must-have. Gas portable water heaters have a lightweight design that makes it easy to travel with this product.  The product has all the necessary safety features so any hazard can be prevented. This CSA approved safety best selling product is safe according to all standards. This unit gives you enough hot water while camping, hiking, or any outdoor sports.




Low water pressure needed

Energy saving

41000 BTU per hour water supply



Less durable


Key features :

Lightweight design:

The unit is designed especially for travelers so it is easily portable. You can get an instant continuous hot water supply no matter where you are. You can enjoy a warm water bath anywhere with this gas water heater.

Requires low input water pressure:

You just need 2.5 psi water pressure to operate. This makes it easy to connect it with any water source. The unit provides 1.58 gallons of water per minute. The temperature and flow of water are adjustable.

Comes with a showerhead:

The unit has a shower end at the water output end so you can easily use the water for your needs. Moreover, these designs make water wastage less likely and are convenient for bathing while traveling.

High safety system :

The overheating protection feature saves water from becomes unbearably hot. Similarly, an anti-freezing drain prevents water from collecting inside the unit and affecting function.

Rinnai RUC98iN Ultra Series Indoor Natural Gas Tankless Water Heater, Twin Pipe

With indoor installed units the amount of space occupied is a major concern. The units placed on the floor occupy the space permanently moreover the nearby area needs to be clean and clear as well so the unit will not get damaged. Rinnai gas tankless water heater design is perfect for indoor installation. The unit has about 95 percent thermal efficiency which makes it budget-friendly.



Low nitric oxide emissions

Concentric and PVC venting option

95 percent thermal efficiency

Comes with a pressure relief valve



Expensive installation cost


Key features

Low nitric oxide emissions :

The low emission rate makes this product eco-friendly. Less environmental impact makes this product the best choice for the long run.

Less space needed:

This unit needs indoor installation so the design is according to need. A small compact design fits the space and won’t occupy much area. The unit is installed on the wall so floor space is not occupied like the traditional tank water heaters.

Natural gas fuel:

The unit is powered by natural gas. This benefits the buyer due to its low cost and easy availability. Using a gas heater causes less monthly bill cost than electric ones.

Concentric venting:

A Concentric vent has both input and output pipes. Concentric venting makes the vent cooler and this offers enhanced safety benefits.


Eccotemp i12-NG Tankless Water Heater

Eccotemp tankless water heater has a sleek modern design that gives a visual appeal to the product. Glass front panel gives the unit a very good look. The elegant design unit can provide 3-gallon water per minute that works only on demand and this feature reduces unnecessary energy consumption. The energy-saving mode of the unit adjusts usage according to needs and prevents any unnecessary water wastage.



Self electric ignition system

No pilot light needed

Sleek design

Reduced energy consumption



Does not work above 5500 feet


Key features


Touch screen LCD at the front shows both output water temperature and gallon per minute flow rate. This unit has an impressive 3 gallon per minute flow rate.

Horizontal vent:

This heating system has a stainless steel horizontal vent kit. The system comes pre-assembled and is easy to self-install. A power cord that works with a 120 volt supply is used for powering the exhaust fan and the digital temperature display screen.

Automated unit:

This system is a fully automated system that needs no pilot light. Gas is consumed only when hot water is on.

3 gallon per minute flow rate:

The flow rate of this system is enough for use by a small family. Opening multiple faucets at the time will affect the flow rate.


Takagi T-H3-DV-N Condensing High-Efficiency Natural Gas Indoor Tankless Water Heater, 10-Gallon Per Minute, 199,000 BTU

Takagi heating system is apt for heavy residential use like space heating or domestic recirculation. This unit is well suited for both residential as well as commercial purposes. This unit can be used at about 10,100 ft altitude. The output supply is enough for 3 to 4 faucets at a time. The required gas input is 100000 BTU. Due to low nitric oxide emissions, the negative impact on the environment is very less.


Pros :

10 gallon per minute

Copper alloy heat exchanger tubing

Works up to 10,100 ft altitude

Built-in water temperature control panel



Loud noise while functioning


Key features

Enhanced safety features:

Takagi has installed many safety features in their unit for the protection of the unit and its durability. The freeze feature inhibits water from freezing inside the system and the overheating system maintains water temperature at standard limits.

Better heat transfer:

Commercial Grade copper alloy is used for primary heat exchange. This ensures 25 percent better heat transfer than stainless steel.

Low nitric oxide emissions :

The use of eco-friendly products is important for saving the environment from all harmful effects. Low nitric oxide emissions prove the product safe for use in apartments, residential buildings, and commercial places.

Works at high altitude :

This system can be used at 10,100 ft altitude. With just 199000 BTU gas input this system will have enough continuous water supply to be used for 3 bathrooms.


Rheem RTGH-95DVLN 9.5 GPM Indoor Direct Vent Tankless Natural Gas Water Heater

If you own a traditional tank water heater and remain concerned about energy cost, it’s the right time to replace it. The gas tankless water heater will cut down your monthly energy costs. Gas water heaters are more energy-efficient and affordable in long run. Rheem water heater can provide you continuous water supply, unlike the traditional ones. Replacing the older unit will also free up a considerable amount of space.



Smart electronic control

94 percent energy efficient

Industry-standard built quality




Takes time to heat


Key features

Saves space :

If you own a small living space this product will solve your space occupation concern. The compact design fits into a small space and works efficiently.

Smart electronic control :

Smart control enables better energy usage by device. This feature also allows for better safety of the patient by avoiding any leakage or overheating of water.

High quality built:

Due to frequent testing and certification by various organizations, the unit has the high-quality performance. The unit is designed to match the industry-standard quality and last for a long time.

Water Filter maintenance :

The water filters need once monthly cleaning for better performance. Filters can be cleaned by closing the shutoff valve and unscrewing the filter. The filter is then cleaned using water and replaced. At the end open the valve.


Noritz NRC66DVNG Indoor Condensing Direct Tankless Hot Water Heater, 6.6 GPM – Natural Gas

Noritz holds the pride of introducing the first energy efficient, modern water heating system. This quality product can provide 6.5 gallons of warm water per minute. If you face warm water issues every winter due to a big family this product will help you out. Fuel by natural gas this product gives you a continuous water supply. Electric water heaters will not work in power out and cost much more so installing a natural gas water heater is economical.



Advanced heat exchanging design

Thermostat control

Includes a 6-inch power cord

Highly efficient performance



No warranty


Key features

Remote thermostat control :

The temperature of the unit can be adjusted by the thermostat control. The remote function makes it easy to control the unit from distance and adjust water according to need and prevent overheating.

6.5 gallon per minute water flow rate:

The highest flow rate is 6.5 gallons which will be enough for use by most of the families. The water supply is quick and continuous so you won’t need to wait for long to get warm water from your faucet.

Condensing water heater:

The use of Condensing technology makes the system super efficient and a good option for long-term investment. The operating cost for a Condensing water heater is less than all other options available.

Vented with standard PVC pipes :

Schedule PVC pipes and fittings are used for venting this unit. Adapters are available and can be purchased online for different venting options. This modern energy-efficient system can be Self-installed by following the instructions manual.



Without using a storage tank, water can be heated directly through a tankless water heater. These types of heaters provide continuous hot water as they never run out of water. Instead of storing hot water, these tanks’ fewer heaters provide you hot water on your own demand. To your surprise these heaters have one more benefit that houses with water heaters installed sold out easily and more quickly than those without tankless water heaters installed.



8.4 gallon per minute flow rate

Outdoor installation

Low nitric oxide emissions



Filters need to be purchased separately


Key features

Space- efficient:

Rheem water tankless heater manufacturers have done a great job by designing it in a way that it covers less space compared to others. As it is a big issue that many people don’t have much space in their homes so they try to buy those things which give them multiple benefits. Keeping that in mind Rheem water tank fewer heater manufacturers made it with multiple features so that buyers will like it.

High efficiency:

Rheem water tankless heaters are made in a way that they are highly efficient. It has multiple benefits like it can provide hot water at a rate of 8.4 gallons per minute. Another feature which is loved by most people is that it saves energy cost of 108 dollars per year as compared to other heaters.

No maintenance:

Almost everything required maintenance from time to time. This is quite hectic for people. That is why Rheem tankless heater manufacturers made these heaters in this way that they don’t require much or almost no maintenance compared to other ones.

Long warranty:

Things with long warranty are mostly purchased nowadays therefore Rheem water tankless heater manufacturers made these heaters with a life span of more than 20 years. As its parts can be easily replaced so it increases its lifespan.

Ultimate Buyer’s Guide to Buy a Best tankless gas water heater

Are you are still confused about choosing the right product after going through the list of products above? Don’t worry we aim to make your task more easy for you so we have listed the most important features to look for in the best tankless water heating unit next

Energy efficiency :

With heating systems, it is important to make sure the monthly energy cost of your purchased product will be within your budget. Almost 99 percent efficient gas water heaters are available so choose the product that provides efficient results at low cost.

Temperature display and control :

Most units have a digital temperature display at the front so you can easily adjust the temperature according to your requirement.

Design :

The compact design of the heating unit needs less space. You can install the unit into any available space inside your home or nontraditional places like the attic or cabinet. If you own a small space looking for a sleek design product is a must.

Safety features:

High-level safety features ensure better protection from any possible damage. Overheating and freezing prevention safety features protect the product from damage. Similarly, the leak detector feature will make sure your property is safe from water damage.



Overall best tankless gas water heater:

Rinnai V65IN Tankless Water Heater, Large, V65iN-Natural Gas/6.5 GPM is the overall best tankless gas water heater. You can adjust the temperature using a mobile app with wifi monitoring. The flow rate is enough for home daily use.


Best tankless gas water heater for travel :

Tankless Water Heater, GASLAND Outdoors BE158 1.58GPM 6L Outdoor Portable Gas Water Heater, Propane Water Heater, Overheating Protection, Easy to Install, Use for RV Cabin Barn Camping Boat, White is best to the water heater for traveling because of its lightweight. The unit is highly energy-efficient and needs minimal water pressure so you can enjoy a continuous warm water supply during your travel.


FAQs about best tankless gas water heater

What is the difference between gas and electric tankless water heater?

Electric power heaters have a higher monthly cost than gas water heaters. Although electric water heaters are more energy-efficient high electric bills make the unit more expensive than gas ones.


How many fixtures can be used with a water heater?

Tankless water heaters heat water on demand. The water is not stored but heated during travel through pipes so using multiple fixtures decreases the water flow rate. The water is continuously supplied but if multiple faucets are used at once water flow rate will be much less than mentioned.

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