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Best Gas Water Heater Reviews: Propane, Natural Gas Hot Water Heaters

Tankless technology is becoming more and more popular, and this guide aims to reveal which is the best gas water heater that can replace your conventional storage tank unit.

Tankless gas water heaters come with multiple advantages. Producing hot water on demand, they don’t need to consume gas when not in use, reducing your gas bills with up to 40%.

Here's a list of Best Gas Water Heater

That’s a nice chunk to save, but not the only reason to consider replacing your old water heater.

A tankless water heater of the right capacity produces instant hot water for all your household activities. You can use a shower, washer, and the kitchen’s sink contemporarily without running out of hot water or having to settle for a lower temperature.

Compared with their electric counterpart, the tankless gas water heaters perform better in cold weather, a great advantage if you live up north. Furthermore, gas is cheaper than electricity, so these units beat the electric regarding long-term running costs too.

But if you want to take full advantage of a tankless gas water heater’s benefits, it is important to select the right unit. You must consider capacity and volume output among an array of other things.

The market offers a bountiful range of options, and finding the right water heater can be daunting and confusing. Luckily, we’re here to help. We’ve asked our experts to roam the market and identify the top seller, best-in-class, and the best budget gas water heaters running on either natural gas or propane. Check them out below.

Best Gas Water Heater Reviews

  • Takagi T-KJr2-IN-NG - a top-seller product praised for its reliability.
  • Rinnai RUC98iN - the absolute best. A gas water heater that won’t let you down.
  • Ridgeyard RSQ-12YHB - our best budget option that doesn’t compromise on quality.

1. Takagi T-KJr2-IN-NG Gas Water Heater

Takagi T-KJr2-IN-NG is one of the most popular gas tankless water heaters on the market, a product praised for its reliability and relatively low price.

This is one of the smallest units manufactured by the brand, with a caloric power of 140,000 BTU per hour. This translates into an energy factor of around 0.83, just what it takes to heat cold water in the colder climates.

This indoor water heater runs on natural gas,offering one of the most cost-effective solutions in the long run, and provides an average temperature rise of 40°F in cold climate and 60°F in warm climate areas.

Takagi T-KJr2-IN-NG

 This corresponds to a flow rate of about 2.9 GPM to 3.8 GPM, depending on the water demand and input water temperature. At these flow rates, the heater can typically supply one low-flow shower and a lavatory basin or an appliance at the same time.


  • Takagi T-KJr2-IN-NG brings a cost-effective and environmentally friendly water heating solution and is designed to support radiant floor and hydronic baseboard heating applications besides supplying hot water on demand. Perfect for a smaller apartment or standard two-bathroom American home, this tankless water heater is dependable and easy to control.
  • The remote temperature controller brings further value for money, allowing you to set or change the desired water temperature to meet specific demands.
  • Four preset temperature ranges let you choose an output temperature from 113, 122, 131, or 140°F. 
  • Besides all above, the fully modulating unit also incorporates safety features including an air-fuel ratio sensor, exhaust and water temperature safety control, and an overheat cutoff fuse. Moreover, you can also rely on the internal freeze-protection system during the colder months.
  • The tankless water heater supports horizontal and vertical installation.


  • Like most tankless water heaters, the Takagi T-KJr2-IN-NG comes with an indicative flow rate which depends on the actual temperature of the input water and the hot water demand at any given moment.
  • This means the real flow rate could be lower, which is typically not an issue for most domestic applications but influences the unit’s performance during peak demand.
  • A thing the manufacturer doesn’t specify is the unit needs recalibration when used at elevated altitudes. Most natural gas water heaters do, but we’d have expected a reliable manufacturer to be clear about it.

Takagi T KJr2 IN NG Gas Water Heater Video Review

If what you’re after is best in class performance and don’t want to settle for anything less, the Rinnai RUC98iN is no doubt the best gas tankless water heater your money can buy. Yes, you can expect this workhorse to have quite an impact on your bank account, but the investment is well worth every dime.

Much more powerful than our top-seller above, this unit doesn’t lack popularity despite its hefty price.

One of the most efficient indoor models, this water heater is also powered by natural gas and features condensing technology with two heat exchanges developed to improve the unit’s performance.

Rinnai RUC98iN

As a result, this tankless water heater can output energy of 15,200 BTU at 4.5 kWh, which goes up to 199,000 BTU at 58.3 kWh, its peak power.

This is more than enough for most domestic needs, and the unit provides a maximum flow rate of 9.8 gallons per minute, just what it takes to provide an endless hot water supply for residential or commercial applications.


  • Packed with attractive features, the Rinnai RUC98iN appeals to those who need a reliable and energy efficient unit. One of the features that differentiate this unit from the mass is the concentric/twin pipe venting which brings more ventilation options.
  • Assembling is also easy, and all it takes is minimal DIY skills to put this beauty up. You’ll still have to call in a certified plumber to assess the safety of your system, but this will cost you less than professional installation.
  • And the best part is that self-installation is accepted by the manufacturer, which means you’ll not lose your warranty.
  • Another great plus is the ultra-low emission of noxious fumes. With this water heater, you can sleep safely, while the noise level is also minimal.
  • Like most natural gas tankless water heaters, this product is designed to save on energy and consumes drastically less than a conventional storage tank or electric tankless unit.
  • For residential applications, the product is backed up by a 12-year limited manufacturer’s warranty.


  • Praised for the craftsmanship quality and high efficiency, Rinnai RUC98iN could seem flawless. Nevertheless, it comes with some minor downsides too.
  • One is the price. This unit is expensive, and although investing in quality always pays off, this tankless water heater may be out of reach for some homeowners. You will also have to pay attention to the handling of the unit, which is quite sensitive.
  • The lack of a remote controller is not exactly a drawback, but it would have been nice to have one on such an expensive thing.
  • And you’ll also have to pay attention to the service requirements. The manufacturer may cancel your warranty unless all service works are conducted by certified staff.

Rinnai RUC98iN Video Review

3. Ridgeyard RSQ-12YHB

Homeowners shopping on a budget or those searching for a portable gas tankless water heater will find what they were searching for in the Ridgeyard RSQ-12YHB. This propane-fueled water heater is perfect for a small studio apartment and also finds its place in a cabin or traditional one-bathroom home.

It can’t compete regarding output with our two picks above, but it can easily win all contests when it comes to affordability. 

Ridgeyard RSQ-12YHB

Cheap and reliable, this won’t withstand commercial use but will provide sufficient hot water for your bathroom and kitchen.

The propane system is slightly less efficient than the natural gas, but it features mobility. You can install this unit wherever as long as you can connect it to a water source. And when you need to move on, you can simply dismantle the heater and take it with you.

A convenient shower included in the pack even makes this water heater a splendid idea for camping.


  • This highly efficient propane tankless water heater is perfect to use in most settings, even when natural gas is unavailable. Its low water pressure start makes it ideal to use in the kitchen but also with low-pressure showers on a campsite or cabin.
  • An automatic electrical pulse ignition system ensures hot water on demand without any intervention from your side, and the flow rate is also surprising for such a small unit. In fact, this water tank provides up to 3.2 GPM.
  • Another great feature is the 20-minute timer protection and overheats protection, for improved fuel management and safety. Although you don’t have to connect this gas water heater to the main power outlet, you’ll still need two 1.5V batteries to power its electronic components, such as the temperature display.


  • As any propane water heater, this unit is a tad less effective, although more efficient, than a natural gas unit. You’ll have to pay attention to the fuel levels and change the propane tank as required.
  • Propane is also more expensive than natural gas, and if you consume a lot of hot water, this could result in higher running costs for the long-term.
  • Like the Rinnai above, this unit lacks a remote controlling unit. This isn’t necessarily a drawback, but it’s a nice perk that would undoubtedly add more value. Nonetheless, the analog settings are very easy to control and adjust according to your needs.

Gas Water Heater Buying Guide

My purpose in this article is to help you find the best gas water heater for you. You now know which are some of your best options, but how to decide which of them fits your needs? Read our buying guide below to see which are the most important features to consider.

Propane vs. Natural Gas

Either propane or natural gas are great alternatives to reducing your monthly electricity bill, and both fuels are rather inexpensive. But if one is more energy efficient, the other is cheaper.

Propane contains twice the energy of natural gas, which means a cubic foot of propane can output over 2 BTU, whereas a cubic foot of natural gas outputs slightly over 1 BTU. It’s easy to understand a propane water heater needs less fuel to produce the same amount of heat as a natural gas one, but this doesn’t mean propane is necessarily better.

Natural gas is cheaper and comes with added advantages. You’ll have to connect your tankless water heater to the main gas line in your home, and you’re good to go. No more worrying about refilling the fuel or changing the tank.

On the other hand, propane is considered a green fuel, whereas natural gas produces greenhouse effect fumes. In the end, both are valid options, and you can choose based on your circumstances.

Consider Intended Use

What do you need a tankless water heater for? Your home? Your RV? Your log cabin in the woods?

Gas tankless water heaters come as indoor, outdoor, or portable units. The portable ones are always powered by propane, whereas you’ll have the choice of propane or natural gas with the fixed units.

Flow Rate and Temperature Rise

An important thing to determine when buying the best gas water heater is the desired flow rate and temperature rise you require.

Assess the flow rate by calculating how many hot water devices you want to use at a time. The table below contains the average hot water demands of the main devices, and you’ll have just to sum up the ones you use to determine the desired flow rate.

Fixture / Appliance

Flow Rate (gallons per minute)


2-4 GPM

Bathroom/kitchen faucet

2-7 GPM

Washing machine

3-4 GPM


1.3 GPM

To calculate the necessary temperature rise, subtract the temperature of the input water (the water entering the system from the main pipe) from the output (or desired) hot water temperature.

For example, if you want an output temperature of 120°F and the water entering your system is 50°F, the water heater must be capable of producing a 70°F rise in temperature at the desired water flow rate.

These specifications are typically disclosed in the product’s manual, so it should be easy choosing the right model for you.

To make accurate estimations, we recommend measuring the input water temperature via a pipe thermometer, especially if you live in a cold climate area, and round up the calculated results with about 50% to make sure your system lives up to the expectations.

Set Up Costs and Warranty

Before investing in a gas tankless water heater, also consider the initial set up costs and the warranty.

Although cheaper in the long run, gas water heaters have higher upfront setup costs than their electric counterparts, as these systems require proper venting or waterproofing feature in case you decided to go for an outdoor unit.

Installation usually requires professional aid, and some manufacturers will cancel the product’s warranty unless you prove certified installation. There are also some manufacturers who allow for a bit of installation flexibility, but the system will still have to be checked by a certified plumber before the first ignition.

The warranty is another thing to consider. Most manufacturers back their products with a warranty between 5 and 10 years for domestic use, but it’s a great idea to check before you buy.


We’ve introduced you to three of the best gas water heaters on the market, but which one is the best for you must still be determined based on your personal circumstances.

The Takagi is the unit that brings the best value for money for most people. It has great caloric energy and flow rate and is ideal for an average American home with two bathrooms and up to four members. Its flow rate can supply sufficient hot water to at least two fixtures, and you can improve the system’s efficiency by using low-flow showers.

The Rinnai satisfies all hot water demands, in either residential or commercial environments. It is ideal to use in all climates and won’t let down a big family. It does come at a hefty price, but its efficiency will pay off in the long run.

Lastly, the Ridgeyard is ideal for those homeowners shopping on a budget, but it will have slightly higher running costs due to the different fuel employed. This is the only propane water heater we featured due to its excellent energy efficiency. The water heater is also ideal to use in areas where natural gas is unavailable but will need recalibration at higher altitudes.


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