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Best Tankless Water Heater Gas 2018 – Tankless Water Heater Gas Reviews

A tankless water heater gas model is a convenient, cost-effective and energy-efficient way to provide hot water to a home or business. In order to help our readers select the models that are best for them, we researched and analyzed numerous professional tests and reviews of the most popular products on the market.

What Is a Tankless Water Heater Gas Unit?

image of Gas Tankless Water HeaterSince the late 1800s when people realized that having a convenient and consistent supply of hot water was possible, engineers have been innovating solutions for home use. The core goal of any water heater is to provide water at the appropriate temperature and exactly when needed. Although the concept of tankless has been around since those earliest days, it became clear that storage tanks were going to be a practical requirement until technology evolved. A tank allows the water to be heated in advance and drawn as needed.

In the 1970s, technology had advanced enough that the tank could be eliminated from the equation. This tankless approach was called on-demand water heating but also continuous flow, instantaneous and instant-on among other names. These units don’t retain water internally. Rather, the water flows through the device as needed, is heated in the moment and then delivered to the user. This approach eliminated the problem of running out of hot water, but it introduced another one: inefficiency during short water draws. Fortunately, modern innovations have begun to overcome this drawback, and it will be a non-factor sooner than later.

Just like tank-based water heaters, tankless water heaters are available in both electric and gas configurations. The first attempts were actually gas since use of electricity hadn’t become convenient enough to employ in that manner yet. By the 1970s, when these products were starting to become prevalent in Europe and Japan, both electric and gas were an option. Gas then and now has often been a preferred choice because of how inexpensive the fuel is compared to electricity. This usually makes gas a much more economical pick for heating the water in a home. In this context, the term gas can refer to either natural gas or liquid propane.

Natural gas is often the cheaper and cleaner option when available. However, when not available, liquid propane or LP is a fine option as well and can be stored in tank on the property of the home. Regardless of the fuel source—including electricity—many homeowners are switching to tankless and opting for it in new homes because it’s convenient and efficient and modern breakthroughs have overcome many of the faults that were once associated with the technology.

How Does a Tankless Water Heater Gas Version Work?

A tankless water heater gas model has four primary connections. The system has an inlet connected to the main cold water supply line so that it can draw water in. It also has an outlet connected to the main hot water supply line so that it can distribute hot water to the home. There is also a connection to the main gas supply line for the home, and this provides the natural gas or liquid propane that will be burned. Finally, there is an electrical connection. Even though these models run on gas, modern units use electricity to ignite the pilot, power circuit boards and so forth.

When there’s a draw on the hot water because someone started using the kitchen faucet or a shower, for instance, cold water flows into the system via the inlet. The pilot light is ignited, and it heats the heat exchanger. A heat exchanger is called such because it exchanges or transfers the heat from the flame to the water. The system also has an internal thermostat that gauges water temperature, and the exchange of heat is quite fast. Even in older, slower models, the delay is usually seconds at worst.

Many of the products featured in the tankless water heater gas tests of 2017 had a second heat exchanger rather than just one. This makes heating the water a two-stage process. Cold water is first heated by a stainless steel heat exchanger that captures latent heat. In a system with just one heat exchanger, that latent heat would simply be vented. This preheated water is then moved to the primary heat exchanger as described above.

Once the water is at the desired temperature, it flows into the hot water pipes and is available anywhere throughout the home where it is needed. Users are also able to adjust the desired temperature. Many modern systems have a digital display and control panel. Integration with home thermostats is an option, and satellite modules are an option too. As the desired temperature is increased or lowered, the flame output is adjusted accordingly.

These systems can be either point-of-use or point-of-entry. POU equipment is responsible for a particular station, such as a bathroom sink, or a zone, such as an entire bathroom. POE systems, which are also called whole-house/home, affect the main water source and supply hot water throughout the residence. Gas is generally favored for POE and electric for POU. There are scenarios in which POU equipment is used to augment a POE system, such as for the reduced lag time in certain areas of the home.

It’s also becoming increasingly common for tankless water heater gas units to feature recirculation technology. What this does is recirculate hot water that has entered the pipes but gone unused. This not only makes the system more efficient but significantly cuts down on lag time. Many of the newest models are hybrid solutions. They have a small holding tank, which is kept full and heated and is used to provide hot water immediately. This eliminates lag time.

Advantages and Applications

The core application of these tankless systems is to provide hot water on demand. This approach is becoming increasingly prevalent due to all of the advantages it provides.

This trend will eventually cause conventional water heaters to become outmoded. Let’s explore the various benefits over tank-based and electric that were often cited in the studies and reviews we assessed.

From a usage standpoint, the greatest advantage of a tankless water heater gas unit is that the home will never run out of hot water. A family can take as many consecutive showers as needed with worry about draining the hot water tank. Elimination of the tank also means that homeowners are never at risk of flooding due to a ruptured tank. Leaks can still occur, but even these are generally less severe than a leaking tank unless left unchecked.

Cost Savings and Energy Efficiency

Not only do these require a lot less physical space in the home, they are more economical. In fact, the U.S. offers a rebate that most homeowners can take advantage of that is worth at least $300. On average, tankless models tend to last five to 10 years longer than tank-based systems because tank corrosion is a point of weakness. Finally, the EPA estimates that the average homeowner can reduce their energy costs by about 20 percent annually.

What Types of Tankless Water Heater Gas Models Are Available?

image of Tankless water heatersWhen choosing a water-heating solution fueled by liquid propane or natural gas, one of the first choices a consumer has to make is which type. There are three fundamental tankless water heater gas types: non-condensing, condensing and condensing hybrid. There’s also the matter of choosing equipment designed to be installed outside versus hardware that must be installed inside the home.

Indoor and Outdoor

There are pros and cons to the typical units that are installed indoors as well as the equipment intended for outdoor installation. The advantage of an outdoor unit is that it doesn’t require a specialized place. It can be installed almost anywhere on the home and have convenient access to gas, water and power. In addition, it vents directly and doesn’t require specific ventilation. The downside is that they must be built to withstand the elements, often require an enclosure and special precautions must be taken when temperatures drop below freezing. They’re often not a practical option in cold environments. The indoor units tend to be more practical, less expensive and easier to maintain, but there are some downsides, such as the need for ventilation piping and drainage for condensation.


Non-condensing technology is considered the first generation of tankless water heater gas and electric models. These have a heat exchanger that heats water on demand. They are able to achieve an Energy Factor between 82 and 85 percent. The models available for many years in Japan and Europe were non-condensing. It’s not the most efficient approach, but it is well proven and refined. In addition to lower energy efficiency overall—concerning short water draws in particular—a downside to this technology is hot exhaust. It requires particular ventilation made of stainless steel to be installed.


Condensing technology is the second generation. Like non-condensing, these units have a primary heat exchanger. However, they also have a second heat exchanger, and it reuses the heat from the exhaust to heat the water more efficiently. This approach results in an EF between 92 and 94 percent. As a result of the second exchanger, the exhaust is not hot and thus PVC can be used so that the ventilation is cheaper. These models do cost more, and there are still efficiency issues with short water draws.

Condensing Hybrid

Condensing hybrid was innovated in the U.S. fairly recently and is considered the third generation of tankless water heater gas and electric models. These systems feature a holding tank with the usual size being about 2 gallons. This reservoir compensates for the issue with short water draws and increases overall EF to as high as 96 percent. The Gas Technology Institute determined that this approach operates at 94 EF on a far more consistent basis than second-gen models. The downside is that this technology is leading-edge. It’s not as widely available yet, and these systems aren’t nearly as well proven and refined.

How Tankless Water Heater Gas Models Are Tested

Our team examined many different test results and reviews. By analyzing the tankless water heater gas tests of 2017 and paying particular attention to the winners, we we’re able to organize and condense testing protocols to what we feel are the seven core categories.

Gallons Per Minute

Conventional equipment is rated based on the number of gallons it can hold along with its first-hour rating or FHR. These measures don’t apply to tankless solutions, which are measured by gallons per minute or GPM. Tankless means on demand. In other words, hot water isn’t stored. It’s created and delivered as required. GPM is a measure of continuous hot water. The ideal GPM depends on the size of the home and family. There may be many sources drawing hot water at once, including showers, dishwashers and faucets. In terms of rating these products, GPM is generally assessed within the context of cost. The goal is to answer the question how much each gallon per minute is costing the consumer over the expected lifespan of the appliance.

Energy Efficiency

On average, heating water amounts to about 20 percent of residential energy costs. The EPA has thus placed great emphasis on water-heating technologies for the home both in terms of the standards it establishes and the way it rates equipment. This focus was very evident in the tests and reviews that we studied as well. There are numerous ways in which efficiency is assessed but perhaps none is more prevalent than UEF. Consumers can use UEF to compare tankless water heater gas versions, but they can also use it to compare to all manner of household appliances rated in this manner.

Anti-Scale and Anti-Sediment Measures

Depending on where a person lives and how hard their water is, the buildup of sediment and limescale can be a serious concern. These accumulations can reduce the efficiency of these appliances and thus increase the total cost of ownership. Therefore, these heaters tend to require descaling on a periodic basis. Many of the tests we reviewed gauged products based on how they informed users, such as digital displays and LED notifications as well as how convenient and effective the flushing and descaling mechanisms were.

Ease of Maintenance

Along with descaling and flushing, there are often other maintenance requirements, such as cleaning the heat exchanger. Our team focused on how simple and intuitive these measures were as well as how effective they were. Will a seasonal inspection by a plumber be good enough for the non-DIYer? On the other hand, what all will the do-it-yourselfer have to know and do in order to keep his or her unit in peak condition?


Reviewers often emphasized warranties as a means of protecting the consumer investment. Note that these warranties don’t cover labor, and comparisons focused on what the coverage entailed. There may be five-year coverage for leaks, for instance, but only one-year protection for exchangers, electronics, elements and so forth. When available, reviews also included customer service experiences and the ease or lack of the warranty process.

Ease of Use

Testers often rate these products based on ease of use, which is subjective but provides buyers with a concept of the learning curve. It’s important to note that tankless is still new to the majority of homeowners and ideally, a unit should be simple enough that a child can interact with it. The tankless water heater gas test winners tended to be models that offered advanced features but were able to deliver them through a simple and user-friendly interface.

Pay Attention to These Important Factors When Choosing a Tankless Water Heater

image of an automatic tankless water heater Choosing the right tankless water-heating solution for a home is a big undertaking. This is an investment as well as a choice that the homeowner will live with for probably 15 to 20 years and hopefully longer. Toward that end, we’ve identified four core aspects that buyers should really pay attention to when making their choices.

Environmental Factors

Homeowners should assess environment factors before researching possible product choices. Is propane or natural gas an option or both? Is the necessary indoor space available for a tankless system? Are the gas and electrical sources easily reached? Perhaps only an outdoor tankless water heater gas style system makes sense for this home. There are dozens of basic questions that need answers so that consumers can pare down the available choices more easily.

GPM Requirements

It’s important to select a tankless water heater gas type that provides enough gallons per minute for that particular home. This calculation doesn’t have to be precise and are achieved with averages. For instance, the industry estimates that a shower requires 1.0 to 2.0 GPM. If a home has three showers, then 3.0 to 6.0 is required. Bathroom faucets are estimated at 0.5 to 1.5 GPM or 1.5 to 4.5 for all three, or 4.5 to 10.5 GPM for the showers and faucets together. By doing this for an entire home, one can determine the overall GPM that the household will require.

Flow Rates

Consumers should also pay attention to flow rates. How much water is needed at any one time. Note that in the GPM section, we offered GPM as ranges. If those two example showers are never operated simultaneously, then an estimate closer to the low end of the range is probably more accurate. If, on the other hand, both showers are used at the same time often as family members prepare for work and school, then an estimate closer to the high end may be more accurate.

Required Temperature Rise

Consumers should determine the required temperature rise for their particular homes and choose an appropriate model based on that value. The first step is to determine average ground temperature. The EPA tracks this data for us at:
Subtract the average ground temperature from the desired in-home water temperature, which is typically 120 degrees Fahrenheit. This value is the required temperature rise. The rise for a home in Miami, for instance, would be 120 minus 77 equals 43 degrees whereas the rise in Maine, on the other hand, would be 120 minus 42 equals 78 degrees.

An Overview of Seven Leading Manufacturers

After assessing many tankless water heater gas tests, certain manufacturers rose to the top. These are the companies—in no particular order—that are innovating and responsible for many of the best brands, models and features currently available.

  • Rheem
  • Noritz
  • Eccotemp
  • Westinghouse
  • Marey
  • American Standard
  • Bosch

Rheem was founded in 1925 and develops water heating as well as HVAC and pool and spa technologies. The company is a global provider and the largest manufacturer of water heating products in North America.

Noritz is a Japanese company and among the most prolific manufacturers of tankless water heater gas and electric styles. The company launched Noritz America in 2001 in order to meet the sharply increasing demand in that area of the world.

Eccotemp is a family-owned and -operated company based in South Carolina that’s relatively young only having been established in 2004. This brand has a large presence in major retail chains in the U.S. and has become the number one manufacturer of portable tankless solutions.

Westinghouse is an iconic brand and its tankless water heating solutions are one way that it lives on. These products are well regarded industry-wide for their performance, efficiency and overall refinement.

Marey has specialized in tankless water heating since 1955. That makes this Puerto Rico-based brand one of the most respected names in the industry in North America and throughout the world.

American Standard is among North America’s biggest plumbing and building names and has been supplying consumers and contractors for more than 140 years.

Bosch is a global German company, and its water heating technologies are just one way it’s built its name. It’s on-demand heating solutions have long been popular in Europe and are now enjoying great success in North America as well.

Purchasing Online versus Buying Locally

image of man buying best tankless water heater onlineAn interesting choice facing homeowners considering the tankless water heater gas style is whether to purchase online or buy local at a brick-and-mortar shop. Certainly, there are some consumers who might never consider the Internet for such a substantial acquisition. Nevertheless, more and more shoppers are turning to the Web for items that were once considered exclusive to local retail. That includes automobiles, clothing, food, household appliances and even water heaters. There are many benefits, which are becoming increasingly difficult to ignore.

Internet Purchases Are More Convenient

A prevalent theme among consumers who were surveyed is that making purchases online is simply more convenient. Any reservations generally had to do with the cost and the size of the product. Shopping for a system like this locally often means traveling from one store to another, and sometimes those locations may be 30 minutes or further away. With the Web, each online store is only a click away. Better yet, consumers are not restricted to local business hours. If a person prefers to shop late at night from bed after the children have been laid to sleep, that’s a perfectly fine option.

Brand, Model and Feature Choice

Shopping locally lets consumers deal with sales reps in person, and many people enjoy that. The flipside, however, is that the buyer is often limited to the brands and models that are more popular or more readily available in that region. That may not be an issue for those who live in major metropoles, but for the average buyer, it generally means selecting from just a subset of the brands, models, configurations and features that are actually available on the market. The selection on the Internet is much better. No matter how obscure the particular model or feature a consumer has interest in, there will be a shop online and likely dozens or more that carry it.

Sticker Price and Total Cost

Price is a crucial consideration as well, and it may be the lower prices online that are driving more and more consumer to make big purchases via the Internet. The big component here that favors the online retailers is overhead or what businesses refer to as fixed costs. These include rent, utilities, insurance, employee salaries and benefits and so forth. These fixed costs are lower for the online business for a host of reasons, and the seller is able to pass those savings on to the consumer without making less than the brick-and-mortar shop would. Often, it is not just the sticker price that is lower but the total cost of ownership both in the near-term and the long-term.


Whether a homeowner chooses to purchase their new system online or locally, delivery of that tankless water heater gas unit will likely be necessary. These products are often heavy and cumbersome. Local retailers generally charge extra for these deliveries because they outsource to local small businesses that can provide such services on demand. For online stores, deliveries are integral to their operations and they’re often able to provide this service at no additional charge due to the contracts that they have in place with the major delivery companies.

Returns and Exchanges

Many of the people surveyed who had never dealt with a return or exchange with an online store were surprised to find that those who had considered it easier. This was true even with large and expensive home appliances. The reason is that the cost and logistics of a local return generally fall on the consumer. Online, many stores process returns without restocking fees. Additionally, stores can schedule a carrier to pick up the return at the customer’s home. In the case of exchanges due to a defective product, a missing part or a consumer needing a different model, the online retailer is often able to ship in advance of the return being received.

Professional Installation

Other concerns consumer had related to professional installation. Often, the larger local chains will seek to pair these sales with the install. Such services are available online as well. Many retailers coordinate with local plumbers to have tankless water heater gas models installed or can direct the consumer to services that do. Better yet, many consumers benefit from decoupling the hardware purchase from the installer selection in terms of overall cost and convenience.

Our Verdict

During our assessment of these products, we found that consumers who bought online were generally more satisfied with their purchases than those that did not. Those results didn’t surprise us because of the sheer amount of advantages ecommerce offers consumers, and that includes the ease with which shoppers can research their decisions. Buying local is still a perfectly fine option, but it’s hard not to recommend the Internet for both the cost and time savings.

Interesting Facts & Advice

Tankless water heating is a fascinating invention, and being able to use natural gas makes this significant home utility more affordable and environmentally friendly. Technological advances have allowed natural gas pipes to reach more homes in the U.S. than ever before.

In addition, natural gas is so abundant worldwide, the International Gas Union estimates that there’s enough of it to meet all of the world’s energy and electricity needs for the next 250 years! In areas where natural gas is not yet easily accessible, liquid propane can be used instead. This does require installation of a tank, but many service providers offer ways to offset those initial costs for customers who agree to a service contract.

The History of Tankless Water Heaters

image of tankless water heater The first tank-based approach to water heating was introduced in the late 1890s in the United States. Despite the inefficiency of these early attempts, tankless configurations weren’t far behind. In fact, there were tankless inventions just several years later, and in 1929, Stiebel-Elton not only invented the first electric tankless product but made it commercially available. Gas-powered also became available about this time and actually became more popular due how much more efficient they were.

Efficiency was of course relative. The early tankless equipment simply couldn’t compete with tank-based and so that became the standard. It wasn’t until the 1970s that advancements in efficiency would evolve enough to become commonplace. By the 1980s, tankless solutions had become the standard in both Europe and Japan. It wasn’t until the 1990s that they became readily available in the U.S., and it’s taken almost three decades to effect real change. Nevertheless, the U.S. has finally embraced this approach, and this renewed interest motivate breakthroughs that resulted in condensing hybrids.

Figures, Data and Facts About Tankless Water Heater Gas Units

Natural gas is among the most affordable energy sources around. Due to its abundance in North America, prices are at the low range globally and remain consistently low rather than fluctuate like many other fuel sources do.

In fact, the average price for natural gas in the U.S. in 2017 is $13.05 per thousand cubic feet. To give readers an idea of how prices continue to decrease, consider than a decade prior in 2008, that price was more than two dollars higher at $15.76. At the 2017 prices, the average homeowner can heat the water in his or her home for an entire year for about $200 to $300.

How to Install a Hot Water Heater Gas Model in 7 Steps

image of Water Heater Repair, Replacement, & Installation diagram Because a tankless water heater gas version requires connection to both a gas line and an electrical power source, it is generally recommended that the system be installed by a plumber who is licensed and ideally certified for the particular brand and model in question. Nevertheless, we’ve outlined here the seven steps required for a typical installation.

1 Remove the Old Water Heater

Before starting, take precautions, such as disabling the water supply, gas supply valves and power. Isolation valves and circuit breakers can be disabled instead in scenarios where it makes sense to do so. Drain the old equipment of all water. Disconnect the equipment and remove it from the area. Note that most jurisdictions have specific rules and regulations for disposing of and recycling such hardware.

2 Install the Gas Line

Unless a gas line is already in place for previous similar equipment, a new line must be installed. This can generally be achieved by installing a tee and valve in the preexisting gas line. Using black pipe or the flexible style of gas supply line, run a new line from the tee to the point where it can easily be attached to the new equipment.

3 Install the Water Lines

Using copper pipe, extend a new hot water line and a new cold water line from the existing water lines. Run these new lines to a location convenient to the equipment. Ball hangers should be used to secure the copper pipe to the walls. This will also ease the process of adding pipe insultation later. Apply flux to the pipe ends. Slide the pipes and connectors together. Solder the pipes together.

4 Mount the Water Heater

Choose an appropriate location that will allow venting to the outside easily. This equipment has to be mounted about 4 inches away from the wall. Therefore, if there is not already such a mount in place, one has to be constructed using 2-by-4 lumber. Once the mount is in place and secure, the heating unit itself can be mounted to that support.

5 Make All Necessary Attachments

Connect the sediment trap and the shutoff valve according to all manufacturer instructions and recommendations. The gas supply line is then connected to the shutoff valve. Next, connect the water line to the equipment valve according to all manufacturer instructions and recommendations. Enable the gas. Bleed the line if necessary. Test for leaks. Once no leaks are confirmed, disable the gas again until the installation is complete.

6 Install the Vent

Stainless steel vent pipe must be connected to the equipment, which will require a connector, hose clamp and heat-resistant silicone sealant. An elbow can be used to ensure that the pipe is pointing in the direction of the vent. Drill a hole from the inside to the outside through a joist or wall. Create an opening using a vent thimble and bore. Insert the flange and apply silicone caulk. It may be necessary to remove some siding and the like so that the flange sits flush. Those can be replaced after the flange has been secure and a vent pipe and hood are in place. Finally, install the interior flange and run a section of vent pipe from the equipment to the opening.

7 Turn on the Tankless Water Heater

Plug in the equipment. If a socket isn’t available, one will have to be installed. Insulate the hot water pipe that runs from the equipment to the main line. Enable the gas. Follow the startup procedures as provided by the manufacturer in the operations manual.

10 Tips for Care

All tankless water heater gas versions have specific maintenance requirements homeowners will need to adhere to in order to optimize performance, efficiency and life expectancy of the system. Note that the particulars vary from one brand and model to the next and that the details can be located in the appliance owner’s manual.

Safety Precautions

Before performing any of the care recommendations provided here, it is essentially to take measures to protect people and the system itself. These include:

Unplugging the electrical cord from the water heater.
Disabling the circuit breaker for the appliance at the electric panel.
Turning the gas supply off at the manual gas valve.
Turning the water supply off either at the main valve or an isolation valve.
Waiting for the unit and any contained water to be cooler than scalding hot.

1 Test the Pressure Relief Valve Annually

The best tankless water heater gas models will have a pressure relief valve to release water and relieve pressure whenever pressure rises above the allowed threshold. To check this device, simply lift and release the lever a few times. Each time, the lever should easily and smoothly relax into its natural position. This examination should be performed once a year.

2 Examine and Clean the Elements

The elements should be checked and cleaned once a year. Use a dry cloth along with a motorized air duster or portable air compressor to loosen dirt and other debris from the heat exchanger, motor, combustion chamber, vents and fan. Look for obstructions, pipe defects, misshapen gaskets and any other signs of wear.

3 Check the Water Filter

The water filter should be inspected seasonally. Often, these can be cleaned to removed mineral deposits and other buildup. Check the flow sensor and ensure it is able to spin freely. If not, then it may be time to replace the water filter. The filter should always be replaced according to manufacturer recommended time frame.

4 Monitor Descaling Diagnostics Regularly

Practically all of the tankless water heater gas test winners that we considered incorporated diagnostic tools that alerted homeowners to the unsafe buildup of limescale and sediment. It is imperative to flush and/or perform the descaling procedure specific to the model and soon as possible once that notification has activated.

5 Inspect Flame Color and Pattern

All units are equipped with either one or two gas burners. Whenever homeowners perform regular maintenance, they should visually inspect the burner flame. The flame should be consistent and blue in color. If the flame is yellow or red, is smoking or has an irregular pattern, the system should be turned off and examined by a professional immediately to avoid more serious problems.

6 Keep Vent Passages Clear During Winter

It is paramount that vent passages not be covered by ice or snow. When it is snowing and during periods when ice is likely, homeowners should check the vents regularly and clear away any obstructions as soon as possible.

7 Take Precautions During Extended Wintertime Absences

Whenever a tankless water heater gas unit will go unused for an extended period during cold weather, it is necessary to prep the system. Never use anti-freeze. Instead, drain all of the water from the heater as well as adhere to any guidelines in the operations manual.

8 Flush According to Manufacturer Recommendations

These systems should be flushed when indicated, but many users will not get such notifications often because they’re not prone to limescale and sediment buildup. In these scenarios, the system should still be flushed with white vinegar however often the manufacturer recommends or once annually.

9 Consider Mitigating Water Hardness

Any homeowners with well water or city water who have high water hardness will need to flush and/or descale their systems more often. An option to combat this is to install a water softening system, and this measure can often be more cost-effective in the long run.

10 Schedule Professional Inspections as Needed

Even do-it-yourselfers should have their systems inspected by a licensed plumber who specializes tankless water heater gas types. Once every three years is a good rule of thumb. Homeowners who are more hands-off should have their systems professionally inspected annually.

Useful Accessories

image of tankless water heater There’s a number of useful accessories that homeowners can install or have on hand in order to make their water-heating more convenient, product and efficient. Based on the tests and reviews we assessed, we found four categories in particular that came up time and again.

Water conditioning

Water quality can play an important role in terms of efficiency, ease of maintenance and life expectancy. Homeowners who do not have ideal water quality for their equipment may want to consider water filtration. There are both point-of-entry and point-of-use options, and these can trap particulates before it becomes sediment, condition water so that it’s less hard and optimize pH for better performance.

Scale-Cutting Equipment

An alternative to water filtration is scale-cutting equipment that can be attached to the water line and prior to the tankless water heater gas unit. This measure can count down on scale quite a bit. It is a useful option when water filtration is overkill or in scenarios where conditioning is too costly or perhaps not feasible for other reasons.

Remote and Push-Button Modules

This equipment is generally controlled by dedicated control panels. Integration with a smart thermostat is also an option. It can also be useful to have additional modules. These modules can be used to adjust temperature or activate recirculation on points of use, such as in the bathroom. Remote modules are handheld and wireless. Push-button modules can be mounted at any convenient wall location.


There are also a number of supplies that homeowners will find convenient to have on hand. Perhaps have a bucket in the utility area for flushing. Cloths, cleaning utensils and even an air duster are handy for cleaning elements, exchangers and the like. Most manufacturers recommend using basic, undiluted white vinegar to clean out a tankless system. It is a safe alternative to chemical solutions.

Frequently Asked Questions About Tankless Water Heater Gas Models

Along our journey to research all of the significant tankless water heater gas tests, we recognized some patterns with the types of questions that consumers had about these products. What we’ve done here is condense those hesitations into the 10 most crucial concerns.

Does a gas water heater smell?

Does a gas water heater smell?

A well-functioning unit does not smell. The fuel is delivered to the system in a closed manner. The fuel should not produce a smell when burning either. There may be a brief smell near the vent when a system fires up after a period of inactivity. In the event of a persistent or heavy smell, that is an indication of a problem.

Is there a difference between natural gas and propane?

Is there a difference between natural gas and propane?

Generally, the decision to use natural gas or propane in either a liquid or vapor form is a matter of availability. If both are available, then it is simply a matter of cost. Natural gas is generally cleaner and less expensive, but price can vary from one area to the next.

Why aren’t these products ENERGY STAR rated?

Why aren’t these products ENERGY STAR rated?

The gas models are. As of this writing, the EPA had not yet approved rating of electric models. The EPA has, however, recognized the energy efficiency of both the gas and electric tankless approach. Nevertheless, while the efficiency of the gas approach is quantifiable and thus comparable across water heater technologies, electric has proven to be more challenging.

How long does it take to install a gas system?

How long does it take to install a gas system?

A licensed plumber who is experienced with these installations can generally complete the project in three hours or less. This is of course without complications, so if running the gas line is challenging or conversion is necessary, the project can take longer. Regardless of difficulties, it will rarely take a professional more than a day.

Where is a gas system installed?

Where is a gas system installed?

Note that there are both indoor and outdoor models. Additionally, optimal placement depends on access to the fuel source, electricity and so forth. The area also requires enough combustion air, so common placement sites include utility rooms, garages, basements, attics and outside walls.

Can a new system be installed where the old conventional unit is?

Can a new system be installed where the old conventional unit is?

Yes as long as enough combustion air is available, which is not a consideration when choosing or designing a site for a conventional water heater. Note also that tankless models generally require a lot less space, and the digital temperature controller can be placed just about anywhere.

Is the tankless approach more energy efficient than tank-based?

Is the tankless approach more energy efficient than tank-based?

Yes. In tests performed for the Department of Energy as well as independent tests, tankless was demonstrated to be more than 20 percent more energy efficient than tank-based. If all hot water outlets in a home are attached to such a system, energy savings are estimated to be between 25 and 50 percent.

Is gas more energy efficient and cost effective than electric?

Is gas more energy efficient and cost effective than electric?

This is a matter of some debate. Both methods are very efficient. Gas is cheaper, so this approach is often more economical to operate. Others assert that the efficiency achieved by electric per unit consumed offsets that higher costs of electricity.

What does EF and UEF indicate indicate?

What does EF and UEF indicate indicate?

Energy Factor or EF is a measure of the overall energy efficiency of an appliance, including tankless water heater gas types. The Uniform Energy Factor was established by the DOE as a means of standardizing testing procedures. UEF is more useful for testing appliances across all household appliances.

Is it practical to convert from electric to gas?

Is it practical to convert from electric to gas?

It usually isn’t possible to convert an electric model to gas or vice versa. However, if natural gas is available, switching over via new equipment is no more difficult than a standard installation generally. If natural gas is not available at the home, propane may be an option.

Alternatives to Tankless Water Heater Gas Units

Homeowners who want a tankless solution but can’t opt for gas because it is unavailable or impractical should consider electric. Electric models are quite efficient in their own right, and it may eventually bear out that the fuel usage efficiency of these units does offset the added cost of electricity.

The conventional water heater is also an alternative, and while these are not quite as efficient as their tankless counterparts, the technology is well-proven, refined, and widely available.

Further Links and Sources

Our goal here is to provide consumers with all of the information necessary to choose the best tankless water heater gas styles for them and their homes. With that in mind, we’ve also included some additional resources to help buyers make their decisions.

EPA blog
U.S. Department of Energy
Builder Online
Family Handyman

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