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Best Natural Gas Tankless Water Heater Reviews [Top 5 In 2023]

best natural gas tankless water heater

Here is a complete guide to the best natural gas tankless water heater currently available on the market. In this review, we will list down the top 5 alongside with their pros and cons, and buying guides when you are about to purchase one for your home. If you are interested to see why we think they are worthy contenders, then keep on reading.

Quick Answer: The 5 Best Natural Gas tankless water heater

So who is our winner? For those who wants to jump straight to our final verdict, here are our top picks.

best value

  • Offers Advanced Safety Features
  • Durable and Efficient
  • Easy to Install
  • High Water Flow rate


  • Easy Installation
  • Compact Design
  • Energy Efficient
  • Good Written Manual

Why Gas over Electric Tankless Water Heaters?

When talking about water heaters, it is vital to know the different aspects of having gas or electric tankless water heaters. But, let’s not get ahead of ourselves just yet.For starters, gas tankless water allows you to have a higher supply of hot water.

Furthermore, they are a perfect investment if you have many family members who love to take showers. It will also give you enough hot water for dishwashing, laundry and other activities.

Meanwhile, the electric ones might be cheaper, but there are certain drawbacks that could make you go against them. If you want to know more about the electric type, check out our verdict on the best models that are available on the market today.

Top 5 Tankless Water Heaters Comparison Table

We have designed a comparison table below for your easy reference.

However, it is important to note that the positions are in no particular order of importance. Some models may be preferred by others, therefore, please do read in details, which models may suit you the best.

ProductFeaturesOur Rating

Takagi T-H3-DV-N
Dimension: 11.2 x 17.8 x 24.9 inches

Weight: 59 lbs

Flow Rate: 10 GPM

Max BTUs: 199,000 BTU/hour
Price $$

More Details

Rinnai RL75iN
Dimension: 14 x 9.3 x 23 inches

Weight: 50 lbs

Flow Rate: 7.5 GPM

Max BTUs: 180,000 BTU/hour
Price $$$

More Details

Dimension: 18.5 x 9.8 x 27.5 inches

Weight: 82 lbs

Flow Rate: 9.5 GPM

Max BTUs: 199,000 BTU/hour
Price $$$$

More Details

Navien NPE240S-NG
Dimension: 17.3 x 13.2 x 27.4 inches

Weight: 75 lbs

Flow Rate: 11.2 GPM

Max BTUs: 199,000 BTU/hour
Price $$$

More Details

Bosch 520P​​​​​N LP
Dimension: 8.7 x 16.7 x 25.8 inches

Weight: 35 lbs

Flow Rate: 5.3 GPM

Max BTUs: 117,000 BTU/hour
Price $$$$$

More Details

The 5 Top Rated Gas Tankless Water Heaters Reviewed

1. Takagi T-H3-DV-N - Best Tankless Gas Water Heater

Featuring an innovative design, the Takagi T-H3-DV-N heater is a perfect addition to your home or your restaurant. 

This indoor tankless water heater features a highly efficient water flow rate. When we compare it to electric water heaters, it is needless to say that you will have hot water almost immediately. It has a fantastic hot water flow rate of ten gallons per minute - more than enough for all your hot water needs.

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2. Rinnai RL75iN tankless water heater

This water heater is one of the current favorites on the market. Its design might look simple but its performance is solid. It will not take up too much space in your house so you don’t have to worry about insufficient storage.

If you have owned a similar model by the same manufacturer, you might be able to use the same venting ducts.

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3. Rheem RTGH-95DVLN Tankless Water Heater

If you have ever researched for the best tankless water heating units, then you probably already know that the electric ones are often the most energy efficient. However, that statement is not entirely true if you take a look at this model.

This indoor tankless water heater is 94% efficient, which is outstanding when compared to other tankless gas units. In addition, it is a safe heater to keep at your house. Its high-quality design allows you to feel secure, and it is highly unlikely that it will leak. Check out the video below for more detailed information.

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4. Navien NPE240S-NG Tankless Water Heater

Navien is a popular water heater manufacturer, and it's no wonder most people love their designs. The same goes for their NPE240S-NG natural gas model.

If you are looking for a space-saving water heater, this could be the best tankless water heater for you. You can hang it on a wall - it will not take up any floor space in your home.

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5. Bosch 520PN LP Tankless Water Heater

If you have a small family that doesn’t require a great quantity of hot water, then this Bosch model will spark your interest.

For starters, it is not a bulky water heater so you will not have any trouble finding enough storage space in your home. In addition, the design also features the Piezo technology that allows you to ignite it without using electricity.

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Gas Tankless Water Heaters Buying Guide

Before you go out and purchase this heating unit, it is vital to mention a few key factors you should be paying attention to. To help you reach a better decision, here is a list of things you should consider:

The Size of Your Household

You might have a large family that tends to use multiple hot water fixtures at the same time. Because of that, a gas model would be a fantastic choice. However, if you live alone or in an apartment, you probably don’t need a whole-house water heating system.

It is vital to determine your needs beforehand. Otherwise, you will probably spend a lot of money on a unit that just won’t pay off in the future. For smaller sized heater, check out our review here.

Can You Install It Properly?

Before you install these tankless water heaters, you have to check if your house can accommodate them. As you probably already know, these types of water heaters require you to meet certain venting demands. It would be best if you could hire a technician to check if you can fulfil all the requirements.

Can You Pay for the Installation?

In regards to our previous point, the installation of a tankless water heater will probably cost you a lot more than you might have thought. Therefore, before delving further into the matter, it would be wise to calculate the costs in advance and see if your budget can handle them.

Will You Be Able to Survive the Fluctuating Gas Prices?

We all know that installing one means that you will have higher electricity bills. However, electricity rates are somewhat stable. Meanwhile, gas prices could surge in the next couple of years.

The decision is yours, and it will depend on your needs and preferences. But, it is important to take the flow rates into account before making your purchase of the best tankless water heaters.

What Kind of Technology Are You Looking For In Tankless Water Heaters?

Some tankless water heaters come with digital displays and a variety of safety precautions. However, the least expensive options often feature an outdated technology. Still, that doesn’t mean that they are poor quality, although there is a high chance they will fail you in the near future.

What To Do If The Tankless Water Heaters Breaks Down?

This type of heating units are known for their complicated repairs. Even if you find a fantastic technician, it still means that you will have to pay a high fee. These tankless water heaters are complex, and they require more maintenance than you might think.

Can You Afford an Annual Maintenance Fee?

This is an investment that could last you for more than 10 years. However, if you don’t take care of it properly, it can easily break down.

You have to schedule annual maintenance for it, and a technician should properly clean it every year.

Even though you might think you can do it all by yourself, these tankless water heaters have complicated parts, and you will quickly lose your patience servicing them.

>> Looking for the best tankless water heaters to incorporate with your home's floor heating system? Check out this article <<

Gas Water Heater Installation

If you are looking to purchase a gas tankless water heater, then you probably want to know how you can install it. However, even though DIY projects are a fantastic way to test your own skills, we would highly recommend you to contact a professional to install it for you.

There are many guides online that could help you install this type of tankless water heaters properly. Besides, if you have already installed one before, you will be happy to know that the process hasn’t changed that much.

Nevertheless, installing these heaters are not a simple task. A professional will be able to do it quickly and without too much hassle. In addition, he will know how to do it safely. One wrong move when installing this sort of heating unit and you could damage it forever.

Gas Water Heaters Common Problems

We have already mentioned that these units can sometimes experience a few problems. In addition, those issues can lead to expensive repairs that could easily make you go over your “water heater maintenance budget.”

Here are some of the most common problems you will probably encounter.

Mineral Buildup

It goes without saying that it is important to take proper care of your unit. Even the traditional water heaters are prone to mineral buildup.

The scaly buildup can seriously impact your maintenance costs because it will be difficult to remove it if you have left it that way for too long. Therefore, it is, without a doubt, wiser to just contact a technician every year and have him check your water heating unit thoroughly.

A professional will know how to clean it properly, and he will also check it for any other faults.

Warning Messages On The Display

If your tankless water heater has a digital display, there could be some alarming messages there.

It could show an “Exhaust Blockage” message, which is an indicator that there are some issues regarding your venting. If you call a professional, he will use special equipment to check the pipes. The equipment will show even the smallest leaks which we often fail to recognize.

However, if you want to check where the problem is, you should first take a look at the pipes. They should be properly connected and in one piece. If there are holes, even tiny ones, it is essential to replace them as soon as you can.

A blockage could also indicate that there is something stuck in the vents. That could mean that there is a potential rodent infestation, or that birds or wasps have built a nest there. Whatever the problem is, a professional will know how to solve it.

Cold Water

As you probably already know, certain tankless water heaters require you to wait a little bit for the supply of hot water. However, if a family member has used the water supply before you, it could lead to cold water flow.

There is nothing to be alarmed about, though. That just means that there was a small amount of hot water stuck in the pipes when you went in to shower. The water heater started heating a new supply, and it just needed a bit more time to get it to you.

This all ties in with the position of the tankless water heater. If it's too far from your bathroom, then you will have to get used to it - there will be a small amount of cool water at the beginning of your shower.

Not Enough Hot Water

When you purchased them previously, you probably thought that it will be able to provide you with an endless hot water supply. However, if you are using too much of it in multiple locations at the same time, the heater could shut down.

There aren’t many solutions to this problem. You can restrict the hot water use in your house, or you could replace the heater with a bigger unit. In addition, you could also purchase a second unit that will allow you to use both tankless water heaters for different purposes.

When To Replace A Hot Water Heater

Your water heater probably has a decent warranty. But, that doesn’t mean that it will last forever.

There are some clear indicators that will tell you when it’s time to switch to a newer, possibly tankless unit.

For starters, if you notice that there is rusty water coming out of your showerhead, there is a fair chance that your water heater is rusty as well. You can try draining the heater, but if the water is not clear, you will have to replace it. Otherwise, it could start developing holes soon.

If your heater starts producing rumbling noises, then it is probably time to make the switch. Furthermore, if you notice any leaks, then it is better to get rid off it before it starts ruining your home. Leaks can destroy carpeting, as well as your belongings. Moreover, your house could get infested with mold.

Therefore, a gas tankless water heater is an ideal choice if you want to avoid these problems. It can last you for years, and because it doesn't have to use a tank, you will only have to service it once a year.

Frequently Asked Questions

1. Who makes the best gas tankless water heaters?

The best tankless water heater is the Takagi brand. It's T-H3-DV-N model is one of the best we have used so far. It is energy efficient, durable and has a superb flow rate.

2. Are Gas tankless water heaters worth it?

Tankless gas water heaters are worth the money because it can save you more money in the long run. If you have a large family that tends to use multiple hot water fixtures at the same time, it will be a wise choice.

3. How much does it cost to install a Gas tankless water heater?

The cost to install one is around $100 - $450, depending on the plumber's hourly rate. The average hourly rate of a plumber is $50 - $150 per hour.

Final Verdict

Takagi T-H3-DV-N Tankless Water Heater

Our research has shown all the pros and cons of different tankless gas units. However, the winner has to be Takagi T-H3-DV-N tankless water heater.

Its design lets you install it in your home or your restaurant, and it is a highly efficient unit that will certainly save you a lot of money. Furthermore, the safety precautions are a fantastic addition because they will give you an added sense of security while using it.

The installation process is straightforward, and the unit will certainly last you for years. Users often talk about its durability and its high-quality design, and the features it comes with will allow you to keep it in top-notch condition. Its qualities speak for themselves and, with just a few flaws, it is worthy of its price tag.

Although it went against some well-worthy contenders, the T-H3-DV-N is undoubtedly the best natural gas tankless water heater currently on the market.

Our Rating

What we Liked:

  • Durable
  • Superb Flow Rate
  • Advanced Safety Features
  • Energy Efficient

What we Disliked:

  • Only for indoor use

    Verner Ellen

    Hi, my name is Verner Ellen. I am a homebody whose interest is in getting the best home tools and equipments to help with the the everyday house chores. I also love fitness, cooking and grilling. Maintaining a clean and comfortable home is my lifelong passion.