The 7 Best Tankless Gas Water Heaters: An In-Depth Review & Guide for 2023

Are you looking for the best tankless gas water heater on the market? Look no further! 

We’ve got you covered with this list of the best gas-powered models available. Tankless gas heaters are more efficient than a traditional storage-tank water heater and take up less space and supply unlimited hot water. And compared to the electric tankless water heaters, they heat water faster, equip freeze protection, and are ideal for large homes and cold climates.

It also has a longer lifespan and requires less maintenance. So if you’re looking for a tankless water heater that will save you money in the long run and increase the value of your home, a gas tankless water heater is the way to go.

So what are the top gas tankless water heaters on the market? Here are our top four picks:

REVIEWS: The best tankless gas water heaters

1. Rheem RTGH-95DVLN Prestige

rheem prestige RTGH-95DVLN

Best gas tankless water heater for large homes

  • 9.5 GPM max output
  • A natural gas-powered indoor model with direct vent
  • Durable stainless-steel condensing heat exchanger
  • 199,900 BTU/hr heating capacity
  • Third-party efficiency tested by AHRI
  • Low NOx emission
  • Remote electronic thermostatic for desired temperature adjustment
  • Exclusive EZ-link feature for multi-heater connectivity for commercial setup
  • It can make noise when running

The Rheem RTGH-95DVLN Prestige is a top-of-the-line Energy Star-certified gas tankless water heater. It is 94% energy efficient and features a stainless steel condensing heat exchanger. Intelligent electronic controls increase energy efficiency and safety. In contrast, the third-party efficiency listing by AHRI ensures that you are getting the most out of your investment. The exclusive Guardian Overheat Film Wrap prevents water from getting dangerously hot. It also includes Low Nox technology for added environmental protection. 

Equipped with a remote electronic thermostat, the appliance permits effortless water temperature adjustment. Rheem RTGH-95DVLN is backed with a 10-year warranty on parts and labor.

On the drawback side, the heater may be noisier than some of the other options on the market. So be sure to place it in an area where you will not mind the extra noise!


  • Upto 9.5 GPM hot water output in warm climates
  • Whopping 94% energy efficiency
  • Exclusive GOFW layer to prevent water scalding
  • Low NOx output making it Eco-friendly
  • 10 years of warranty backing
  • Support multi-unit linear installation


  • It can be noisy when operating

2. Rinnai RUR98iN Ultra Series

Rinnai RUR98iN

Best Rinnai gas tankless water heater for cold climate

  • Large 9.8 GPM hot water output
  • Indoor tankless model
  • A condensing system that provides max efficiency
  • Tankless rack system (TRS/TRW) compatible
  • Offers both concentric and PVC venting
  • Up to 0.96 EF Factor 
  • WiFi capable
  • Includes built-in circulation pump
  • 12-year warranty on heat exchanger, 5-year on parts, 1-year on labor
  • Some people complain that Rinnai is not honoring the warranty

The Ultra Series Rinnai RUR98iN tankless water heater is among the best gas-powered heaters for multi-bath and commercial setups like laundromats(Find more on commercial tankless water heaters here). It has a flow rate of 9.8 GPM and offers maximum output with minimum space requirements – about the size of a small suitcase. Plus, its condensing technology ensures maximum efficiency. This gas model is designed for indoor installation and is compatible with the Tankless Rack System (TRS/TRW) and 1/2″ gas lines. Rinnai offers both concentric and PVC venting options right out of the box. 

The appliance has a built-in circulation pump, internal by-pass pipe for internal “re-circulation,” MC195T remote controller, thermal by-pass valve, and isolation valves. And if you’re looking for even more convenience, it’s Wi-Fi-capable so that you can control it from your smartphone. 

Finally, the RUR98iN comes with a 12-year warranty on the heat exchanger, a 5-year on parts, and a 1-year on labor (with an optional 5-year labor warranty), giving you peace of mind.

While people are generally happy with this product, some have complained that Rinnai does not always honor the warranty. 


  • It has a 9.8 GPM max flow rate for big families and cold climates
  • Highly-efficient condensing water heaters
  • Built-in re-circulation for faster hot water delivery in large homes
  • An array of safety features for peace of mind
  • Upto 12 years of warranty


  • It can be out of budget for some people
  • Warranty claims with Rinnai can be a hectic experience, as the case has been with some customers

3. Takagi T-H3-DV-N

Takagi gas tankless water heater

Best natural gas tankless water heater for commercial use

  • High-efficiency natural gas indoor model
  • 10 GPM output/ 199,000 BTU
  • Computerized safety features, including freeze, overheat, surge protection, and troubleshooting diagnostic codes
  • Ultra-low NOx emissions
  • Commercial-grade copper heat exchanger for 25x better heat transfer than stainless steel
  • Heats at up to 140F while advertised as 180F
  • Energy star certified
  • A lot of people have complained of leakage within a few years.

The Takagi T-H3-DV-N is a high-efficiency natural gas unit that can shell out up to 10 GPM of hot water, making it an ideal water heater for large household needs in cold climates. It has a compact and space-saving design. It equips intelligent freeze, overheat, surge protection, and diagnostic codes for easy troubleshooting. With a gas input of 199,000 BTUs, the T-H3 can heat up to four bathrooms in warmer climates or three baths in colder climates.

However, please don’t go by the advertised 180F maximum heating temperature; the heating limitation of Takagi is 140F. Also, many users have complained about leakage issues within the first few years of use, so if you plan to buy this model, maintain it regularly.


  • Upto 10 GPM flow rate is ideal for commercial setups
  • Built for cold climates with a range of freeze protection features
  • Superior copper alloy heat exchanger for efficient heat transfer
  • Requires only 120V power input


  • Slightly overpriced
  • The water heater may not be as durable and can leak within a few years

4. Eccotemp FVI12-LP

Eccotemp FVI12-LP

Best budget propane tankless water heater for small home

  • Liquid propane-powered indoor model
  • Upto 4 GPM hot water flow
  • Perfect for any small home, cabin, or apartment.
  • Silent operation with minimal noise
  • Safe 120v electronic ignition system
  • 0.65 activation flow rate
  • ‎2-Year limited warranty
  • ‎80-140F temperature control
  • Some users have experienced not-so-smooth customer service

If you are looking for a gas-fired tankless water heating solution for your small home, apartment, or cabin, then Eccotemp might be the right choice. The FVI12-LP is a high-capacity indoor unit with upto 4 GPM output in warm climates of Florida. It’s also quieter than most other tankless water heaters. Eccotemp features a safe electronic ignition system and requires 120volt input. It uses 1/2″ NPT pipe fittings and has manual thermostatic temperature control. What’s not so exciting about this tankless unit is its activation flow rate which is slightly on a higher node, plus not so welcoming two years only limited warranty.


  • Best budget gas tankless heater for tiny homes
  • Delivers up to 4 GPM max hot water output
  • Requires only 120v input for electronic ignition


  • The 0.6 GPM activation flow rate is slightly high, so the heater won’t ignite if you open the 0.5 GPM tap.
  • It comes with only a two-year warranty
  • Warranty claim experience can be rough if the situation arises.

5. Camplux CA318 LP

Camplux CA318 LP


  • Upto 3.18 GPM hot water flow
  • Trendy design with black tempered glass front panel 
  • Available in gas & LP variant
  • Easy to use LED display controls.
  • Equips anti-freezing and dry combustion protection along with flame failure device
  • Temperature control ranges from 95-149F(35-65C)
  • It comes with child-locking technology
  • Horizontal stainless steel vent pipe.
  • 82,000 BTU heating capacity

The Camplux CA318 is a high-performance tankless water heater that delivers hot water at up to 3.18 GPM, making it suitable for households with multiple people or medium demand. It features automatic temperature control and child-locking technology, making it easy and reliable. The trendy aesthetics and easy-to-use LED display make it a great addition to any home, and the safe electronic ignition system eliminates worries about accidental fires. The appliance also incorporates a horizontal stainless steel vent pipe for indoor installation. It has an 82K BTU heating capacity and is available in liquid propane and natural gas options.

The Camplux Instahot is the perfect choice if you don’t use a large amount of hot water.


  • Ideal for tiny homes, cabins, and barns
  • Available in NG and LP fuel options
  • Stylish design
  • Freeze and dry combustion protection


  • Not for multi-bathroom houses



Best portable outdoor gas tankless water heater

  • Upto 1.58GPM hot water output 
  • Overheating protection
  • Ideal for use in RV, cabin, barn, camping boat
  • Low 2.5 PSI water pressure is needed for heater ignition
  • Upto 41,000 BTU heating capacity
  • Equips flame failure, anti-freezing, & overheating protection
  • Automatic gas shut off on unexpected flame failure
  • 11.5% energy-saving technology. 
  • It may not be as durable and long-lasting.

Gasland BE158B is a portable gas water heater for outdoor use. The heater can also be installed indoors in cabins or barns if a flue pipe or duct is installed and well-ventilated. The unit has a maximum heating capacity of 41,000 BTU/hr. It has crucial safety features, including overheating and a flame failure shield to ensure your family’s safety. The tankless water heater is CSA-approved as safe per Canadian and US norms.

However, many complain that the product did not last more than a season before it broke down. To top it off, the compact and lightweight structure is not as durable as some people would like. Overall, the Gasland Outdoor BE158B Tankless Water Heater is a decent product at an affordable price tag. Still, it has some drawbacks you should be aware of before purchasing. Find top RV tankless water heaters here.


  • Portable and lightweight, that’s best for outdoor use
  • Ideal for RVs and off-grid use
  • Requires minimum water pressure for activation


  • Many people complain about its durability and that it doesn’t last more than a season.
  • Ideal for single fixture use only

7. Rinnai RL94iN

Rinnai RRL94iN

Best non-condensing gas tankless water heater

  • Non-condensing natural gas indoor model 
  • Shells out up to 9.8 GPM max output
  • Equips original Circ-Logic technology to match your hot water usage pattern
  • Includes 12-, 5-, and 1-year residential warranty for exchanger, labor, and parts, respectively
  • Up to 40% more energy efficient than the conventional tank model.
  • Smart WiFi connectivity is available
  • A lot of people noticed poor service and inconsistent hot water

If you’re looking for the finest heater for the money, the Rinnai RL94IN is an excellent choice. It provides up to 9.8 GPM of hot water in warm climates, making it ideal for use with up to six fixtures simultaneously. This intelligent water heater features durable construction and a range of safety features, including an automatic shut-off valve that prevents overheating for safer operation in residential and commercial applications.

The Rinnai RL94IN is the size of a small suitcase and can be easily installed in a wide variety of spaces.

Besides, the heater is provided with a self-diagnostic system that detects and alerts you of potential problems.


  • Compact size that’s easy to install in a variety of spaces
  • Can supply upto 6 hot fixtures simultaneously
  • Extensive residential and commercial warranty


  • Customer service at Rinnai can be a headache
  • Sometimes hot water temperature can be inconsistent 
  • Not easy to install for DIY enthusiasts and requires professional help

BUYING GUIDE: For the gas tankless water heater

tankless water heater buying guide
Appliance store

Size and capacity

The size of the tankless water heater is an essential factor to consider. To size a tankless water heater, you must ensure it’s big enough to meet your peak-hour hot water needs. For example, if you have two hot showers (1.5GPM) and a dishwasher (1GPM) running simultaneously, you’ll need a flow rate of at least 4 (1.5+1.5+1 = 4) GPM.

Activation/ minimum flow rate

The Activation/minimum flow rate is the minimum water you need to call for the heater to activate and provide hot water. If your heater’s minimum flow rate is 0.7GPM and you open a faucet with 0.5GPM flow, the heater won’t start, and the water you get won’t be hot—so the lower the MFR, the better.

Temperature rise

The temperature rise is the difference between the incoming cold water and outgoing hot water temperatures. You’ll want to choose a model with a high-temperature rise if you live in an area with cold winters. 

The hot water output is inversely proportional to temperature rise. For, e.g. If your cold water is 50F and you want hot water at 95, then the max output will be higher than wanting the same cold water to heat to 105F.

BTU and Energy Efficiency

The BTU (British Thermal Unit) measures the heat output of the water heater. The higher the BTU, the more powerful the heater is. 

However, the BTU doesn’t tell you anything about the heater’s efficiency. To know about the efficiency, you must look at its Energy Factor (EF). The EF measures the percentage of the energy converted to hot water. The higher the EF, the more efficient the heater. For instance, a 0.84 EF, in simple terms, implies burning 1 dollar’s worth of gas; the heater uses 84 cents of it to heat water.

Fuel type

Gas tankless water heaters are mainly powered by two primary fuel types: propane and natural gas. Propane is usually more expensive than natural gas but is also more efficient. Each has its pros and cons. If you’re unsure which fuel type is best for you, compare fuel availability and price in your locality.


Climate is another critical factor when choosing a gas tankless water heater. If you live in cold climates, you’ll need a model that can handle low temperatures and offers built-in freeze protection. It helps the unit to operate in temperatures as low as -30 degrees Fahrenheit.

Condensing or non-condensing

There are two main gas tankless water heaters: condensing and non-condensing. Condensing tankless water heaters are more efficient than non-condensing models but are more expensive.

Condensing unit emits relatively cooler flue gas; thus, even cheaper, easier-to-install PVC venting will do. Non-condensing, on the contrary, discharges very hot exhaust gas, which demands expensive stainless steel venting. If you are on a budget, then a non-condensing model should be fine.

Additional features

Features like WiFi control and a built-in re-circulation pump are not necessary but can add convenience to your life. The WiFi feature allows you to control the heater from the comfort of your phone, and Re-Circ pumps help improve the hot water delivery time. Still, it can add to the unit’s overall cost.


When choosing a gas tankless water heater, it’s essential to look at the warranty. Some manufacturers offer up to 20 years, while others provide shorter warranties of 5 years or less. There is also varying warranty for labor, parts, and the whole system. Make sure you read all warranty details.

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FAQs: For the best gas tankless water heaters

What is the most reliable gas tankless water heater?

When shopping for gas tankless water, it’s best to with reputed brands like Rinnai, Rheem, Navien, and Eccotemp so you can get reliable performance from them round the clock. Some of the most reliable gas water heaters are mentioned above.

Which brand of tankless water heaters is best?

The best brand of tankless water heater is Rinnai, Rheem, and Navien, all of which are US manufacturer and are backed with robust warranty coverage. For more on u003ca href=u0022 data-type=u0022postu0022 data-id=u0022484u0022u003etop water heater brands, click hereu003c/au003e.

What is the downside of a tankless water heater?

While tankless water heater offers an edge over tank water heaters, there are still some downsides you should be aware of before opting for one. For instance, you can not enjoy hot water during a power outage as it doesn’t store hot water. So if you live in a region with power issues, think through or arrange a generator. Check u003ca href=u0022 target=u0022_blanku0022 rel=u0022noreferrer noopeneru0022u003ethe pros and cons of tankless heaters hereu003c/au003eu003ca href=u0022 data-type=u0022postu0022 data-id=u0022139u0022u003e.u003c/au003e

What size tankless water heater is needed for a shower?

If you need to supply hot water to a single shower or hot water tap at a time, then a 2 GPM tankless water heater is more than enough.

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