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7 Best Tankless Gas Water Heaters in 2023 – Reviews and Buying Guide

If you’ve been into a grocery store lately, you can’t have failed to notice the price rises. Whether it’s a loaf of bread or a gallon of milk, costs are going up. In fact, inflation is at its highest point in 40 years and it’s still rising!

And if you’re watching your groceries bill with a worried eye, wait until you hear about energy prices. Energy is at a premium at a time when we need to be tightening our belts.

If you’re thinking about cutting back on hot showers to save money, then wait a hot second.

And don’t go skipping breakfast to save a few bucks. There’s a better way to save on your monthly budget.

In an era defined by rising energy costs, you can’t look past tankless gas water heaters for their exceptional energy and cost-efficiency. While the original price point might be off-putting for many people, it’s time to start thinking long-term.

So let’s take a deep dive into the best tankless gas water heaters. Are you ready for a tankless task?

The Best Tankless Gas Water Heaters in 2023

If you’re hot to trot, here’s a quick look at the best tankless gas water heaters on the market.

Premium Choice
Rinnai V65eN
Rinnai V65eN
  • Excellent 6.5 GPM flow rate
  • Highly energy efficient
  • Hefty 10-year warranty
View on Amazon →
Runner Up
Eccotemp i12-NG
Eccotemp i12-NG
  • Sleek black design makes it aesthetically pleasing
  • Glass touchscreen control panel
  • Fully automated
  • Designed for 1-2 persons household
View on Amazon →
Best For Easy Installation
Camplux Instahot
Camplux Instahot
  • 3.2 GPM flow rate
  • Excellent safety features
  • Designed for usage in small homes
View on Amazon →
Best Mid-Priced Condensing Unit
Noritz NRC66DVNG
Noritz NRC66DVNG
  • Impressive 6.6 GPM flow rate
  • Condensed heat lead to greater efficiency
  • Easy to use
View on Amazon →
Best For A Maximum Flow Rate
Rinnai RU199iN
Rinnai RU199iN
  • Whopping 11 GPM flow rate
  • Condensing design
  • 15-year heat exchanger warranty
View on Amazon →
Best For All-Round Efficiency
  • Impressive 9.5 GPM flow rate
  • Excellent 94% energy efficiency
  • Expensive
View on Amazon →
Best All Round Tankless Water Heater
Takagi T-H3-DV-N
Takagi T-H3-DV-N
  • 10 GPM flow rate
  • Made with commercial-grade copper in the heat exchanger
  • Excellent product for high capacity
View on Amazon →

Ready to give it some gas? Here are the best tankless gas water heaters for any budget in 2023.

1. Rinnai V65eN Natural Gas Tankless Hot Water Heater, 6.5 GPM – Best For Long Term Reliability

Rinnai’s compact tankless gas water heater is a space-saver that you can install almost anywhere in or outside of your home.

Rinnai V65eN
  • Energy efficient
  • Enhanced scale detection protects the unit
  • Compact and easy to install
  • Mid-priced water heater
  • Great warranties on offer
  • Limited flow rate

The wall-mounted unit preserves precious floor space and the heater’s modest dimensions make it perfect for a smaller home.

And with just a 6.5 GPM flow rate, it’s best suited to homes with a smaller hot water demand too. Families could max this out with a couple of simultaneous showers while someone else does the dishes for a change.

But for modest hot water requirements, it’s a premium unit with plenty going for it. By heating water on demand, it saves energy (not to mention your energy bill) and it’s rated by the Uniform Energy Factor (UEF) for its efficiency.

It’s a solid unit, built to withstand constant use. Rinnai builds most of their own components which ups the overall build quality and reliability. The enhanced scale detection reduces the risk of long-term damage from hard water and a hefty 10-year warranty for the heat exchanger secures your peace of mind.

It’s easy to use – just set your required water temperature up to 140°F, and leave it to run. And it’s compatible with Smart WiFi technology, but you’ll have to splash out separately on the wireless controller.

Bottom Line Rinnai’s V65eN is cost and energy-efficient. It’s well built and has a warranty to prove it, and it includes enhanced scale reduction – so it’s our best pick for long-term reliability. View Latest Price on Amazon →

2. Eccotemp i12-NG – Best On A Budget

Eccotemp’s i12-NG is a stylish tankless heater on a budget. It has a limited capacity, but for 1-2 person households it’s seriously cool and easy to use.

Eccotemp i12-NG
  • Stylish design that won’t ruin your kitchen’s look
  • Fully automated controls
  • Glass touchscreen controls
  • Built for DIY installation
  • Child safety lock
  • Super-limited flow rate

The glass and steel design and the sleek black finish give the i12-NG a modern look that will fit into your kitchen or bathroom’s overall aesthetic – this isn’t a traditionally industrial-looking tank. That makes a big difference if you’re installing the heater at the point of use.

And with just a 3 GPM flow rate, you’re unlikely to be using hot water in two places at once with this tankless heater.

Controlled by a touchscreen and including fully automated settings as well as a child safety lock, it’s an intuitive system that you can choose to set and forget. However, there’s no remote control or smart control features – Eccotemp has put simplicity at the forefront of the model.

It’s also designed for DIY installation and includes all standard fittings required for a seamless installation. Great for those who like to do the work themselves.

Bottom Line A super stylish small tankless gas water heater. While the flow rate is constricted, for modest hot water requirements this is a great option at a low price point. View Latest Price on Amazon →

3. Camplux Instahot Instant Water Heater – Best Tankless Gas Heater For Easy Installation

Another really stylish tankless gas water heater that’s designed for modest use in small homes and cabins is Camplux’s Instahot Instant Water Heater.

Camplux Instahot Instant Water Heater
  • Additional safety features and child lock
  • Stylish model suitable for indoor installation
  • Super easy installation
  • Great value for money
  • Limited flow rate – suitable for small households only
  • Tech support falls short

The black glass fronting and LED control panel gives this the look of a giant smartphone and it’s just as intuitive to install. Temperature and pressure information on the screen let you adjust the system to perfection.

With a 3.2 GPM flow rate, this isn’t a model for big families with high water consumption but for a hot water hit in a small household, it’s a great value option. It’s also exceptionally easy to install, with intuitive instructions and simplified venting. Gas connectors and horizontal venting are included with the unit.

The 6-in-1 Protection ensures that the heater works safely and the child lock feature further protects your family.

Note, however, that for every 1000’ over 2000’ elevation the heater loses around 10% efficiency and it’s vulnerable to freezing in harsh conditions. With care, this heater can perform in your mountain cabin but it’s best suited for milder climates.

Bottom Line For easy use and super easy installation, Camplux’s instant water heater goes with the flow. View Latest Price on Amazon →

4. Noritz NRC66DVNG – Best Mid-Priced Condensing Water Heater

Condensing heaters tend to be higher-efficiency and easier to vent than non-condensing tankless water gas heaters and Noritz’s NRC66DVNG is a perfect example of this optimized technology.

Noritz NRC66DVNG
  • Condensing heater leads to greater efficiency
  • Simplified venting with PVC piping
  • Remote temperature controller
  • 6.6 GPM flow rate
  • Designed for indoor use
  • Some wastewater produced

That means you can vent this model with regular PVC piping, rather than stainless steel – so you can expect a simplified setup and exceptional efficiency from this water heater.

The efficiency also allows it to produce more hot water, faster – giving you an impressive 6.6 GPM flow rate – enough for 2 to 2.5 bathroom households’ hot water requirements.

While the Nortiz requires indoor installation and won’t cope with freezing temps outside, it’s not the most stylish model so you’ll probably want to stash this heater in the basement or closet. However, a remote temperature controller gives you complete control from a distance of your tankless gas water heater.

Nortiz hasn’t gone to the lengths of including everything you need for installation, including the valve kit. If you’re planning on a DIY install, make sure you shop around for the necessary ingredients.

It’s a mid-priced unit that offers good value for the flow rate it offers. And the condensing design should make for a cheaper installation.

Bottom Line Exceptionally efficient and producing a decent flow rate, this is a great tankless gas water heater of the condensing design. View Latest Price on Amazon →

5. Rinnai RU199iN Natural Gas Condensing Tankless Hot Water Heater, 11 GPM – Best For A Maximum Flow Rate

Rinnai’s RU199iN features condensing technology and an astonishing flow rate – but it comes with an extraordinary price tag. Can it justify it?

Rinnai RU199iN
  • Phenomenal flow rate
  • Condensing design for exceptional efficiency
  • External pump reduces the wait time for hot water
  • Easy venting
  • 15-year heat exchanger warranty
  • Eye wateringly expensive
  • Large size & indoor installation take up space in your home

The whopping 11 GPM flow rate makes this model unstoppable no matter what your hot water requirements may be. Four bathroom households can shower and flush to their heart’s content without any loss of flow.

The external pump reduces the wait time for hot water once the heater fires up too, and Rinnai’s Circ-Logic recirculation system smartly defines the recirculation pattern to fit your hot water usage. That means you’ll have endless hot water and it’s always on tap.

The condensing tankless system is more efficient than non-condensing models, and it’s also cheaper to install. Despite the extraordinary price tag, this will save you money immediately as well as in the long run.

And a 15 year warranty on the heat exchanger gives you long-term peace of mind. Because Rinnai builds most of their components themselves they’re renowned for competent build quality.

There’s also the option of smart control via WiFi to bring your home’s hot water heating system into the 21st century.

This is a seriously big water heater and, despite the space-saving tankless design, it still takes up a large amount of wall space. So it’s no surprise that Rinnai recommends professional installation, too.

Bottom Line A truly premium tankless gas water heater with an almost endless capacity and 21st-century features. View Latest Price on Amazon →

6. Rheem RTGH-95DVLN 9.5 GPM Indoor Direct Vent Tankless Natural Gas Water Heater – Best For All-Round Efficiency

Rheem’s maximum capacity tankless gas water heater offers a substantial flow rate and extraordinary efficiency, both with regard to energy and water.

  • Impressive flow rate
  • 94% efficiency
  • Remote electronic thermostat
  • Compatible with PVC venting
  • Additional water-saving setting
  • More compact size
  • Top tier price tag
  • Challenging installation for the DIYer

First, the efficiency: Combining an impressive 94% energy efficiency with added water-saving settings that can save you over 1,000 gallons a year, this expensive unit might turn out to save you big bucks in the long run.

And the 9.5 GPM flow rate is adequate for all but the most water-demanding households. Several showers and the kitchen sink can run at once without any pressure drop.

The condensing system means you can install it with PVC piping to vent, rather than expensive stainless steel venting. However, installation is highly complex and any errors will quickly void the warranty, so a Rheem certified engineer install comes recommended, adding to the price tag.

It’s a compact unit that will fit into any water closet – which it benefits from, as the industrial design isn’t built for a modern kitchen or bathroom. Control is via a remote electronic thermostat which gives you quick and easy access to temperature adjustments.

Bottom Line Rheem’s impressive efficiency makes this condensing tankless gas water heater stand out from the crowd. Despite a hefty price tag, its water and energy-saving will help your wallet in the long run. View Latest Price on Amazon →

7. Takagi T-H3-DV-N – Best All Round

As your family grows, you face a conundrum: less space than ever, but increasing demand for hot water. Takagi’s T-H3-DV-N provides the solution: premium flow rate within a compact unit that saves space wherever you install it.

Takagi T-H3-DV-N
  • Great value for a high capacity
  • Impressive 10 GPM flow rate
  • Fully automated and computerized safety features
  • Copper-alloy heat exchanger for better heat transfer
  • 15-year warranty
  • Still an expensive model
  • Indoor use only

With 10 GPM of hot water accessible, you’ll have virtually limitless capacity for hot water in your house. The highly efficient condensing design loses less heat and Takagi has replaced steel for commercial-grade copper in the heat exchanger for a better heat transfer – up to 25 times better in fact.

And while it doesn’t come cheap, for 10 GPM it’s hard to find a better value high output water heater on the market. The 15-year warranty and exceptional efficiency boost the value of this heater too.

Safety features are fully computerized, taking the stress out of water heater safety. The thermostat controls are integrated into the model, making temperature adjustment a bit of a hassle if you’ve hidden it away in your water closet or basement.

Installation is relatively straightforward and Takagi has a great reputation for customer service so if this is your first tankless gas water heater install, you’re in good hands.

Bottom Line Balancing efficiency, price, and capacity, this is an impressive water heater that ticks all the boxes. View Latest Price on Amazon →

Before You Buy: The Tankless Gas Water Heater Buying Guide

Splashing out on a tankless gas water heater is a big decision. Here’s everything you need to know to find the perfect heater for your home.

Why Tankless?

Imagine keeping 50 gallons of water warm, day in, day out, for when you need it. Pretty inefficient. Tankless water gas heaters heat water up when you need it, making them far more efficient than conventional water heaters.

What Are The Pros Of Tankless Heaters?

Tankless heaters are increasingly popular – here’s why.

  • They’re between 30% and 50% more efficient than conventional heaters.
  • Energy efficiency lowers your energy bills.
  • Because there’s no huge water tank they’re much more compact.
  • You’ll never run out of hot water.

What Are The Cons Of Tankless Heaters?

But there are a few downsides to tankless heaters.

  • They tend to be more expensive than conventional heaters.
  • There’s a short lag between turning on the hot tap and the water heating up while the heater kicks in.
  • They require venting so installation can be more complex.
  • In hard water areas, scale build-up can be a problem.

Why Are Gas Water Heaters Better Than Electric?

Tankless water heaters can be powered by electric or gas – but gas is a popular option because they’re so much cheaper to run. The cost of natural gas to power your tankless water heater will save you money every month on your utility bills.


Condensing water heaters are more efficient as hot gasses are captured and used as a secondary heat source. If you’re looking to optimize the efficiency of your heater, condensing water heaters are a great choice but don’t forget they produce wastewater from the gas as it cools and needs to be appropriately drained.

Flow Rate

Tankless gas water heaters produce endless hot water, but they can only produce so much hot water at once. This capacity, measured as the flow rate in gallons per minute (GPM), is important to get right for your home’s hot water requirements.

For single-person households or couples, a capacity of 3 GPM may be adequate but larger homes with multiple bathrooms could require 10-11 GPM to facilitate showers around the house.

Size and Design

Tankless gas water heaters are always considerably more compact than water heaters with tanks, but space is always a consideration. Due to the requirements of venting, you should ensure there’s enough room around your heater for it to properly breathe.

Most tankless hot water heaters are wall-mounted, further saving space. The largest ones will take up a great deal of wall space, however. Space will be a consideration as to whether the heater fits in a utility closet or basement, or is mounted closer to the point of use.

Design becomes important if you’re mounting the heater in your kitchen or bathroom. In 2022, a number of brands have upgraded the aesthetic of their heaters with black glass and stainless steel designs that will match your modern kitchen. Others still look more industrial and are best hidden in the basement.


Because of the requirements of gas lines, electrical ignition, and water pipes, tankless gas water heaters are complex and often expensive to install. A DIY installation is an option, but ensuring your plumbing and piping are in place beforehand will help the job go smoother.

Despite being more expensive initially, condensing tankless gas water heaters are actually easier, and cheaper, to install because they have simplified venting requirements and PVC venting can replace more complex stainless steel.


Lastly, elevation plays a significant role in the performance of your tankless gas water heater – particularly important if you’ve got a cozy mountainside cabin. Many heaters will lose around 10% efficiency for every 1000’ above 2000’, and often this loss of efficiency might undermine the cost-saving impact of gas power.

Tankless Gas Water Heater FAQ

Your burning tankless gas water heater questions are answered here. Hands up!

How Do Tankless Gas Water Heaters Work?

Tankless gas water heaters heat water on demand. When you turn on your faucet or shower the tankless gas water heater will begin heating water with a gas burner, using a thermostat to gauge the temperature of the water coming in and heating it to the desired output temperature.

What Does A Condensing Water Heater Do?

Condensing heaters are more efficient because, thanks to a second heat exchanger, they use the hot gas produced by the water heater as a secondary heat source. The gas is additionally used to heat your water and, once cool, condenses into wastewater. Condensing water heaters must therefore be drained appropriately.

Will A Tankless Gas Water Heater Save Me Money?

Tankless gas water heaters cost more to purchase, but they’re highly efficient and use less energy to heat your water. The Department of Energy calculates that for homes with moderate hot water consumption, tankless gas water heaters are between 24% and 34% more efficient, and, for gas-powered tankless heaters the savings could be over $100 a year.

With an average lifespan of around 20 years, a tankless gas water heater can certainly save you money in the long term.

Are Gas Tankless Water Heaters Cheaper Than Electric?

Gas-powered tankless water heaters cost more to purchase and are usually more expensive to install. But because natural gas is cheaper than electricity, your energy bills will be lower with a gas water heater. The Department of Energy estimates that for moderate hot water consumption, the difference between gas and electric could amount to savings of $64 a year.

Can I Install My Own Tankless Gas Water Heater?

Many tankless water heaters are advertised as suitable for home installation, but connecting water and gas lines makes it a complicated and high-consequence job. Condensing tankless water heaters are easier to install than non-condensing systems.

Does Hard Water Damage A Tankless Gas Water Heater?

Hard water can damage a tankless gas water heater due to the build-up of scale within the system. When installing a tankless gas water heater it’s a good idea to consider installing a water softener upstream of your water heater to protect your appliances.

What Is A Cold Water Sandwich On A Tankless Gas Water Heater?

A cold water sandwich occurs when warm water sitting in your pipes comes out instantly when you turn on the faucet. This warm water is followed by cold water from outside your home before the water heater finally kicks in and the water turns hot.

Cold water sandwiches are common for tankless heaters and you often need to wait a few seconds before you get your hot water. Modern heaters have a recirculating loop which helps water flow back to the heater instead of sitting in your pipes.

Wrapping Up…

Tankless gas water heaters are a compact and efficient addition to any home and with cheaper running costs and impressive lifespans, they’re a great option for the budget-conscious household.

And while they have a reputation for expensive price points, brands like Eccotemp and Camplux are proving that for modest hot water requirements you can find tankless gas water heaters on a modest budget.

Meanwhile, Takagi and Rinnai are producing exceptionally powerful gas water heaters that will keep you getting into hot water with your whole family!

If your water heater is coming to the end of its lifespan, you have to consider going tankless. It’s time to turn up the heat on tankless gas water heaters.

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Eric Phillips

Hi, I’m Eric, a Plumber, Home Repair Expert and Chief Editor behind Dripfina. I first became interested in water purification and water safety when I spent a couple of years traveling the world. I not only learned the importance of keeping my own water fresh and pure (yes, sometimes the hard way…) but I also saw how important water is as a resource worldwide. Read more about me...

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