The Best Tankless Water Heaters Reviewed

We’ve dedicated this comprehensive write-up to helping you pinpoint the right tankless water heater for your needs. We’ve included complete reviews of all 7 of our favorite products, an overview of the top brands, and a buyer’s guide on how to successfully navigate the category when shopping for your own tankless water heater. Let’s get started!

Our top pick for the best tankless water heater of 2023 is the gas powered Rinnai V75iN due to its combination of performance and value. The energy efficiency of this unit will help you save money, while the 7.5 GPM flow rate will be enough for most homes’ hot water demands. However, everyone’s needs are different, so we recommend reading on for our complete review of this model and our other top picks.

When compiling our list, we scoured the market looking across the best brands and the top rated tankless water heater models. Then, we sorted through them carefully, highlighting each product’s unique features in the summary table below so you can quickly make the right decision. Let’s go!

Our List of the Top 7 Best Tankless Water Heaters

Top Picks
Best For
1. Rinnai V75iN
Best Value Gas Tankless Water Heater
  • Best Value Natural Gas
  • Indoor Installation
  • 7.5 GPM

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2. EcoSmart ECO 27
Best Budget Electric Tankless Water Heater
  • Best Budget Electric
  • Indoor Installation
  • Up to 6 GPM

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3. Rheem RTEX-18
Best Budget Electric Tankless Water Heater
  • Best Value Electric
  • Indoor Installation
  • 4.4 GPM

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4. Stiebel Eltron Tempra
Best Premium Electric Tankless Water Heater
  • Best Premium Electric
  • Indoor Installation
  • Up to 7 GPM

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5. Noritz NRC66DVNG
Best Premium Gas Tankless Water Heater
  • Best Premium Gas
  • Indoor Installation
  • 6.6 GPM

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6. Takagi T-H3-DV-N
Best High Volume Gas Tankless Water Heater
  • Best High Volume Gas
  • Indoor Installation
  • 10 GPM

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7. Bosch Tronic
Best Mini Tank Water Heater
  • Best Mini Tank
  • 7-Gallon Tank

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Tankless Water Heater Reviews – Our Top Choices Reviewed

1. Rinnai V75iN Review

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  • ThermaCirc360 technology
  • No more water wasting
  • Mobile app for remote control
  • Efficient and space saving
  • Easy to install and use
  • Expensive

No waiting time

There is no need to wait for hot water to come out your faucet! It will always be available when you need it. Now, you don’t have to choose between chores. You can run the dishwasher, do the laundry or take a shower without a problem maintaining hot water.

ThermaCirc360 technology and water savings

This innovative feature works by recirculating hot water through the pipes so that you will always have hot water when needed. You can also rely on water savings all the time when you choose this tankless water heater. There is no need to waste water each time.

Space saving

The Rinnai V75iN tankless hot water heater is also yours if you want to save space. It is not bulky, so it does not waste an inch of space. This indoor installation water heater is small yet efficient. It has a compact design, allowing for quick installation. It can fit a small suitcase that you can also set it up in a crawl space, an attic or a closet.

High water flow rate

The indoor installation water heater that runs on natural gas can offer you up to 7.5 GPM of water flow rate, making it one of the most effective around. However, it also varies based on the temperature of groundwater.

2. EcoSmart ECO 27 Review


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  • Compact, stylish design
  • Stainless elements for durability
  • Occasional bouts of cold water (if the problem persists, install a valve to control the flow rate)

The EcoSmart ECO 27 is a compact, highly efficient model with enough capacity to heat water for two showers running simultaneously. Reasonably-priced, it is arguably the best electric water heater if you’re on a tight budget. Ideal for a small household, cottage or cabin, it will save you up to 50% on electricity bills thanks to the patented modulation system, which increases its energy efficiency by up to 99.8%. For those interested in technical data points, this water heater has a flow rate of up to 6 gallons per minute.

Digital Temperature Control

Sure, any tankless water heater worth your money should allow you to control temperatures painlessly, right? Well, that’s what you get with the EcoSmart ECO 27, but with a little twist. It enables you to increase the temps in 1-degree increments. That way, you can set the exact temperature more precisely depending on what your own uses of the hot water.

Generous Flow Rate

The ECO 27 will give you up to 3 gallons of hot water per minute in areas with temperatures as low as 37 degrees Fahrenheit. In areas where the temperature of the incoming water is high, such as the southern United States, it can heat nearly 6 gallons per minute. Theoretically, this means that you can power up to four showers and a sink at the same time without running out of hot water. Brilliant!

Other notable highlights include digital temperature control and easy-to-replace elements.

For our full review of the EcoSmart ECO 27 follow this link

3. Rheem RTEX-18 Review

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  • Rheem Reliability
  • Precise Temperature Settings
  • Install In Tight Spaces
  • Energy Efficient
  • Not For Larger Homes

The Rheem RTEX-18 is nearly our top choice among electric water heaters in our list and provides great value as either a whole house solution (typically up to 2 Bathrooms) or in a point of use application.  It is so compact that it provides a lot of flexibility in installation locations, it could even fit under the counter.  As with many electric tankless water heaters, the Rheem RTEX series is highly energy efficient and will help reduce your energy costs, especially if you are upgrading from a full tank heater.  Note that installation will require 240V and adequate circuit protection, so make sure you have the proper electrical requirements.

Small / Compact design with big output

This electric tankless water heater is great for a tight installation, whether it is under the counter or in the back of a small utility room, the compact casing (less than 19″ on the longest dimension and less than 4″ thick) can fit in most spaces.  However, don’t let the size fool you, this heater still packs enough power to be the hot water source for a small to medium size house (great for up to 2 bathrooms).  Flow rates can exceed 4 GPM. 

Easy to operate and maintain

Buyers of this electric tankless water heater will appreciate the digital temperature display and ease & precision for changing temperature.  Just use the dial on the front to set your ideal temperature in 1 degree increments.  This unit is also easy to maintain and very durable.  Most of the heating elements are easily interchangeable and widely available from many sellers due to the widespread distribution of Rheem. 

Advanced Self-modulation

This technology is designed to increase energy efficiency and reduce your costs.  This feature quickly heats water when you need it to provide instant hot water on demand.  When you don’t, the heater conserves energy, saving you money. 

4. Stiebel Eltron Tempra 29 Plus Review

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  • Five-star performance
  • Energy efficient
  • Automatic flow rate
  • Relatively expensive

Leading off our best water heater reviews is this model by Stiebel. A high-end unit and one of the most powerful tankless water heaters you can find, it is a great pick if you live in cold regions where the temperatures of incoming water can drop to as low as 40 degrees Fahrenheit. It is a brilliant choice if you’re looking for a heater with a high flow rate (this thing can heat up to 8 gallons per minute depending on the temperature of the incoming water).

Advanced Flow Technology

The Stiebel Eltron touts a brand-exclusive technology that adjusts the flow of water automatically when it senses that the demand is higher than the heater can handle. Do you know what this means? Well, it means that you’ll always enjoy the hot water at constant temperature, unlike most heaters that start to produce cold water when the flow exceeds the heating capacity.

True Thermostatic Temperature Control

The Eltron isn’t in our best water heater roundup by some fluke. It is one of the few models that adjust power based on the temperature of the incoming water and flow rate. It will modulate its power output to match the heating demands of the incoming water to maintain the desired temperature of the water coming out of your showerhead or tap. Nice!

Intuitive Temperature Display

You’ll never have to guess the temperature at which the Eltron is heating water. It has a large display that shows you the temps in an easy-to-read digital format. Besides, it has a highly responsive dial selector that allows you to set the temperatures anywhere between 86 to 140 degrees Fahrenheit. In short, this tankless heater is excellent in every way. We only wish it was cheaper.

We go into more detail with our Stiebel Eltron 29 Plus Tempra review.

5. Noritz NRC66DVNG Review

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  • High Efficient
  • Compact Design
  • Remote Thermostat Included
  • Premium Price Point

The Noritz NRC66DVNG is a premium gas tankless water heater with a flow rate to support most residential needs.  This model is designed for an indoor installation, and produces low Nox emissions which can be vented using common PVC piping.  Noritz’s condensing technology helps produce a high 0.91 energy factor, which sets this unit apart from other gas tankless water heaters around this price point.  The NRC66DVNG is also the smallest gas unit in this review providing the maximum flexibility for installation, especially in small spaces

High performance in a small package

This model is one of the more compact gas tankless water heaters on the market, but still manages to match the output of much larger models.  Operating at up to 120K BTUs the NRC66DVNG can support a flow rate of up to 6.6 GPM, enough to operate multiple fixtures or appliances at the same time.  Additionally, the 0.91 energy factor ensures that the heat is applied in an energy and cost efficient way. 

Noritz quality reputation

Noritz specializes in tankless water heaters, it is all they do.  Such focus on tankless technology has made them a leader in terms of quality and reliability.  They have also built a world class customer service organization, providing support and assistance with any aspect of installation of service.  Noritz also controls all aspects of manufacturing, ensuring quality parts and construction throughout the unit

Long lasting, backed by a leading warranty

As you would expect from a company with as strong of a reputation as Noritz, their heaters are extremely durable require minimal maintenance. Noritz also supports their quality claims with some of the best warranties in the tankless water heater market, up to 12 years on certain core components.

6. Takagi T-H3-DV-N Review

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  • Can link with up to four heaters with no additional tools required
  • Comes with factory-installed power cords
  • Allows PVC venting
  • Expensive but deservedly so

The Takagi T-H3-DV-N is the best on demand water heater in this collection if you want a model that can rival the traditional tank heater. Gas-powered, this unit has a flow rate of a whopping 10 gallons per minute the highest of any water heater in the roundup. If you’re scouting for a single tankless heater that can take care of all your hot water needs, this one is it.

199,000 BTU Per Hour

The Takagi T-H3-DV-N thrives on its iconic power. With its superior output, this heater will provide a continuous supply of hot water for up to four bathrooms at the same time and three in a colder climate. It also has an commendable 0.95 Energy Factor. It is an ENERGY STAR certified model as well.

Computerized Safety

One of the primary concerns you should have about choosing your tankless water heater is its ability to keep you and your family safe. The brains behind Takagi T-H3-DV-N know this very well and as such, have automated this unit’s safety functions. From the built-in diagnostics and temperature controls to internal freeze protection systems, everything about this heater regarding safety is on point.

Revolutionary Heat Exchanger

The Takagi T-H3-DV-N comes with a durable commercial grade copper heat exchanger. This specific function allows it to heat water on demand within seconds. And then there is the direct power vent that gives you plenty of options for where to mount it within your home. Other notable highlights include the electronic ignition for ease of operation and the ultra-low NOx condensing technology to control emissions.

7. Bosch Tronic 3000 T 7-Gallon Review

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  • Compact and lightweight
  • CFC-free foam insulation for optimal energy efficiency
  • Glass lined tank for extended use
  • Affordable
  • Stylish design
  • Supports multiple placements
  • Not ideal for large homes

Our reviews wouldn’t be complete without mentioning the 300T by Bosch Tronic. A cost friendly option, this is a perfect pick if you don’t have the money to splurge on the more expensive models. Make no mistake about it though; this unit may be affordable, but it doesn’t fall short on functionality.

Compact Build

The Bosch Tronic 3000 T is the smallest water tank on this list. Yes, it’s even smaller than the Takagi T-KJr2-IN-LP. So compact is this thing that it can fit under a sink cabinet. And, because it has an attractive, trendy design, this heater will blend seamlessly with your interior décor.

Point of Use Installation

You can mount the 3000T virtually anywhere, indoors and outdoors. The beauty of it is that unlike other models that require venting, this is a point of use heater, which, by extension, means that it is a plug and play unit. In fact, all you have to do to get it to work is to tap into your cold water line and mount it directly simple and straightforward. With such flexibility, this heater is great for your garage, patio kitchen, basement wet bar or powder rooms.

Reasonable Heating Capacity

The Bosch Tronic 3000 T may be small, but its heating ability is impressive. It heats water at a temperature range of 65 to 145 degrees Fahrenheit, which is enough for most needs in a typical household. Meanwhile, the flow rate of 7 gallons per minute is more than enough. Note: the 3000 T is also available in 2.5 and 4-gallon capacities.

We go into more detail with our full review of the Bosch Tronic 3000 T.

Tankless Water Heater Brands

Numbers indicate that some tankless water heaters brands are more popular than others. These manufacturers have set the bar by consistently churning out top models backed by a reliable performance. If you’re scouting for the best tankless water heater, there’s every chance that you’ll end up with one of the following brands.


Navien is a manufacturer of a premium line of gas tankless water heaters with a focus on energy efficiency. In fact, their standard condensing unit reaches an EF of 0.99, which means there is very little loss in energy when the unit is operating. You should, however, expect to pay a bit more for their products than other tankless brands. Additionally, Navien does not sell their products online, so you’ll need to find a certified dealer or installer in order to purchase one. If you’re interested in learning more, check out our Navien tankless water heater review, where we go much deeper on this brand.


Rheem has been perfecting the art of making top-notch tankless water heaters for more than nine decades. This company thrives on innovation and smart technology. Their best selling model is the Rheem RTGH-95DVLN, a powerful gas-powered heater with brilliant EF. For a company whose motto is to give you intelligent appliances for comfort, this manufacturer based in Atlanta Georgia will indeed continue to find its way into homes for years to come. You can read reviews of Rheem tankless water heaters for details on various models.


EcoSmart claims to give you a heater that will work twice as fast as those from other manufacturers. Their models are small and a hit with homeowners who don’t have a lot of space. And, just as the name suggests, EcoSmar’s mission is to generate and distribute quality green products. By the look of things, they’re doing exactly that and the consumers seem to agree. All EcoSmart water heaters have ETL certification so they’re safe to use. Did you know that EcoSmart is the only electric tankless water heater brand whose models have a FIDE certification? Well, now you know.


TAKAGI has made a name for making tankless water heaters with ridiculously high flow rates. Their electric models are compact too. But, it is the commendable performance that has made this brand a crowd favorite. Their water heaters seek to give you the best possible flow rate even in high altitude areas. In short, TAKAGI lives up to its slogan of giving you endless hot water! See our TAKAGI tankless water heater reviews for more on different models.


While Rinnai is a relatively new entrant into the market, it has cemented its name as a brand to reckon when it comes to making world-class tankless water heaters. Based in Nagoya, Japan, Rinnai manufactures both electric and gas-powered water heaters. Fans applaud their excellent customer service and the long warranties attached to their model. In essence, this shows that Rinnai believes in the quality of their products and are not afraid to stand by it. We’ve reviewed a range of Rheem tankless water heaters in detail.

Stiebel Eltron

Stiebel Eltron is a Germany manufacturer of home heating appliances that has been plying its trade since 1924. Their tankless water heaters use state of the art mechanisms and are also one of the most advanced. They’ve proven to be a popular choice for people living in high altitude areas to due to their brilliant temperature rise. Stiebel Eltron claims to give you access to clean and crisis-proof heating solutions and we couldn’t agree more.

Bosch Thermotechnology

Bosch is yet another Germany tankless water heater manufacturer with headquarters in Wetzlar. This brand is all about making small and highly energy efficient units with the frugal homeowner as the target. Those who’ve used their water heaters remark that they provide hot water instantaneously, further justifying the company’s invented for life motto. See our Bosch tankless water heater reviews for more on different models.


Artmor, a rising name in the tankless water heater industry, boasts innovative engineering and cutting-edge designs. Notably, their units are designed with a dual filtration system which ensures longevity and reduced maintenance. Many consumers have also praised Artmor for their commitment to sustainable practices, evident in their eco-friendly materials and energy-saving technologies. Dive into our comprehensive Artmor tankless water heater review to discover why this brand is making waves.

Benefits of a Tankless Water Heater

The number one reason you’d want to install a tankless heater in your home is cut down energy bills. Tankless units can help you save up to 40% on your monthly utility bill. Now, that’s more than 30% efficiency in comparison to a tanked water heater.

Other than being healthy for your wallet, tankless water heaters bring forth a myriad of benefits including;

You’ll Never Run Out of Hot Water

Tankless water heaters, by design, are on-demand heaters. In essence, this means that they’ll provide you with hot water whenever you need it. Think of them as heaters that allow you to enjoy the hot water at the press of a button.

Besides, you’ll never experience standby heat loss with these models. It is also worth noting that these heaters only require enough power to heat the amount of water needed at any given moment.

Unmatched Durability

Is your old tanked water heater nearing the end of its lifespan? Well, a standard tankless water heater will last you five to ten years longer compared to a tanked version. While most tankless models are high-end with high-end prices, the durability, by extension offers value for your money in the long run.

Compact Design

One of the major differences between tankless and tanked water heaters is that you don’t need a lot of space to mount the former. In fact, a tankless water heater should save you space and offer multiple placements on your wall. Most models that we’ve reviewed above offer indoor and outdoor installation complete with an anti-freeze kit. You can even opt for a smaller unit that can fit under your cabinet or closet for closer point of use.

Eco-Friendly Operation

Gas tankless water heaters have near zero emissions and are, therefore, safe for the environment. Most gas-powered models use low NOx technology to keep emissions as low as possible. Even the electric tankless water heaters don’t generate harmful greenhouse gas. Moreover, these heaters come with innovative features to prevent scalding water from reaching your showerhead or faucet.

Easy to Operate

It doesn’t require a lot of knowledge to operate a tankless water heater. The hardest part of using these models is installation. Once you’ve mounted yours all you need to do is to set the temperature on the unit’s dial and you are good to go. You may even choose a model that supports remote control for hands-free operation.

No Possibility of Flooding

Unlike tanked heaters, you’ll never have to worry about possible flooding caused by a ruptured tank. This goes back to the point that tankless heaters are safe for you and your household. Speaking of safety, some models come with an integrated system that detects internal faults as they occur and give you a warning in advance.

See? There is indeed more than one reason you should purchase a tankless water heater. The only thing you should remember is to check the flow rate of the unit you plan to get before spending your money on it. At the end of the day, you want a model that can handle your hot water needs, whether it is for residential or commercial applications. Note – We will explain about water flow and why it is important in greater detail in our buyer’s guide below.

How Does a Tankless Water Heater Work?

In order to make the most out of your tankless water heater, you must understand how it operates. But before then, let’s start by breaking down how a tanked water heater works. The traditional heater system has a large tank that holds and heats the water. To give you hot water, the tank heats continually to ensure that the water stays at a constant temperature. The energy needed to keep the water hot when you are not using it is known as standby heat loss.

Tankless water heaters, on the other hand, only heat the water when you need it, which means that there’s no standby heat loss. In fact, it is the lack of standby heat loss that makes tankless heaters more efficient.

The Heat Exchanger

A tankless water heater uses a heat exchanger to increase the water’s temperature. A heat exchanger is a device that works by transferring heat from one source to another and is common in car radiators, air conditioners, and refrigerators. In this scenario, the incoming flow of water activates the heat exchanger. In other words, when you turn on your hot water tap, it triggers the incoming water to circulate through the exchanger which in turns heats the water at your preferred temperature.

The Lag Time

Tankless water heaters are available in two options; whole house and point of use heaters. Whole house heaters are typically large, costlier and can work with more than one outlet at any given time. Point-of-use heaters, however, are small with the capacity to heat one or two outlets. Due to their size, they can fit in your closet or under a cabinet.

One benefit of this type of heater is that you can install it close to your water outlet to avoid water loss caused by lag time (the amount of time it takes for your water to reach to the faucet). In big households, the lag time can run up to several minutes. Theoretically, this means that while your utility bill may be going down, your water consumption will be going up. So, consider pondering about the lag time and how it affects your budget before deciding to go tankless.

As you may have already figured out, tankless water heaters come in either electric, natural gas or propane models. Almost every other point of use unit on the market is electric. Whole house models are natural or propane powered. Of course, the model you go with and the heating source that best works for you depend on a host of factors. Again, we shall look at these factors in our buyer’s guide that is coming right up.

How to Choose the Best Tankless Water Heater [2023 Buyers Guide]

While you may read water heater reviews to determine which the best model to choose is, it goes deeper than that. The thing is, tankless water heaters are expensive, and you can’t afford to make an error when selecting one for your household. What follows is a compilation of the most important considerations to make.

The Energy Efficiency

As stated, one of the benefits of going tankless is the energy efficiency these heaters have to offer. It, therefore, makes perfect sense to weigh how much the model you intend to purchase will save you in terms of utility bills. So, be sure to look at the Energy Factor (EF) before buying as it determines the overall efficiency. The higher the EF, the more efficient the water heater is.

Even then, a high EF doesn’t necessarily translate to lower operating costs. Electric systems, for instance, have a higher EF in comparison to their gas counterparts. But, because gas is relatively cheaper, they tend to offer a lower annual operating cost. Here is a practical example.

A gas-powered heater can give you a 70 degrees Fahrenheit temperature rise if it has a flow rate of 5 gallons per minute. However, an electric model will only deliver up to 2 gallons per minute for the same temperature rise.

The Size

Of course, you can only invest in a specific tankless water heater if it can meet your needs. You have, therefore, to examine the model’s temperature rise and the flow rate. At the very least, you should expect your tankless water heater to deliver anywhere between 2 to 5 gallons of hot water every minute. And as we’ve seen, gas-powered water heaters can provide a higher flow rate in comparison to electric systems. To be safe, confine yourself to finding a unit with a flow rate of 8 gallons per minute. Better yet, you can use the following guidelines.

  • Bathroom faucet: 3.0 – 5.0 gallons per minute
  • Shower: 1992 4.0 – 8.0 gallons per minute
  • Kitchen faucet: 3.0 – 7.0 gallons per minute

Also, keep in mind other appliances that you may need to use such as washing machines and dishwashers. Other than that, you need to calculate the temperature rise to make sure that you are selecting the right model. To do so, deduct the temperature of the incoming underground water from your preferred hot water output temperature.

Let’s say the incoming water temperate is 50 degrees Fahrenheit, and you set your output temperature at 120 degrees Fahrenheit. In such a case, you need to choose a tankless unit that can heat the incoming water at a temperature of 70 degrees to reach your desired temperature of 120 degrees. You should remember that the temperature rise will keep fluctuating throughout the seasons, all-round the year. Plus, the temperature of the incoming water will have an impact on the flow rate and speed of your heater.

The Fuel Type

This is indeed a critical decision to make when shopping for a water heater. The best on demand water heaters should offer a continuous flow of hot water while helping bring down your energy costs. By now, you know that there three fuel types to choose from; electricity, propane, and gas. The fuel available in your area of residence determines the type of tankless water heater that you select. It is always important to compare the cost of each fuel type before making your decision.

Other Equally Important Considerations

The Fuel Supply Line -Your line of fuel supply has to be sized to provide the power needed to deliver instant water whenever you need it. Most gas tankless heaters have an output of about 200,000 BTU.

Ignition: There are three types of ignition systems. Expensive models have a complex ignition system in comparison to cheaper units. It is worth noting that the simpler the ignition system, the less the savings the heater will claim.

Venting: Gas tankless heaters require venting for proper functioning. While you can let the vents run through the rough horizontally, you’re better off picking a unit that supports category III venting for better combustion. Even then, it is essential to note that you’ll ONLY require venting if you pick and indoor gas tankless water heater.

Lastly, if you decide to go with an outdoor gas tankless water heater, you should make sure that it’s robust enough to endure the beating of weather elements. Select a model that features an anti-freeze kit.

Frequently Asked Questions

And now, we list down the most commonly asked question in regards to tankless water heaters.

Is it possible to replace my existing tanked water heater with a tankless option?

Yes, it is very much possible. However, we must mention that you have to address some specific requirements before you can go tankless. First of all, you have to know that gas heaters (if you decide to go that route) require a special vent pipe. You’ll also need to have access to a stable gas supply line that will not only feed your water heater but also other appliances connected to that gas pipe. If you invest in an electric water heater, you will need a bigger gauge wire and breakers than the ones you’re currently using with your tanked water heater.

Is it safe to install a tankless water heater in my attic?

Okay, to begin with, it is impossible to give a definite yes or no answer to this question without seeing your plumbing piping. Nonetheless, before you decide to install mount a tankless water heater in your attic, you must be sure that you will not create a possible water siphoning condition. This is because your heater should not have air in the lines. Water siphoning, irrespective of the type of heater you are using may damage your system when there is not enough water in the lines.

I would like to install a tankless water heater in my vacation cabin or home. Is it possible to drain all the water when I’m not using the system to prevent freeze damage?

Yes, it is possible with most models. However, we recommend that you check with the manufacturer just to be sure. If you are given a green light to drain it, all you need to do is to empty both lines to and from your heater. Keep in mind that as long as there are no check valves, that is enough to drain all the water. And, just to be sure that there is no water in the heater we suggest that you empty in two halves. One before and after the unit, you should also consider blowing air through your water heater.

Is it advisable to install my own tankless water heater?

Well, in most cases, we wouldn’t recommend that you install your tankless water heater. In fact, almost all the time, the local plumbing code doesn’t allow you to do so. It may also interfere with the warranty and that is something you don’t want to do. Other than that, there’s every possibility that you might damage your heater even when you have the experience.

You see, most houses don’t have the required electrical configuration for safety and best performance. Besides, you may have to install 240-volt wiring. And, unless you’re replacing a gas-powered tankless water heater, you will also need gas lines and a gas meter for the upgrade. We’ve not even mentioned the venting requirements with most gas tankless water heaters and the actual plumbing that goes into mounting the unit. In short, when it comes to installing a tankless water heater, you’re better off hiring a plumbing professional.

I read that you cannot install some tankless water heaters in certain areas. How true is that?

Yes, there are some states and cities that don’t permit the installation of specific models of tankless water heaters for various reasons. It is therefore essential that you check with your local authorities before ordering for your heater.

Note, particular heaters such as 3-phase or de-ionized heaters don’t come with a return policy. The last thing that you want is to get stuck with a heater that you can’t return or one you can’t install due to local code restrictions.

Why don’t any of my tankless water heaters show the first-hour rating?

Tanked water heaters show the first-hour rating. The amount of hot water the heater can generate in an hour when the tank is full typically determines the first-hour rating. The case is different when it comes to tankless water heaters. You see, a tankless option doesn’t start with a tank of hot water, so it is not practical to expect it to have a first-hour rating as is the case with the tank option. What you get with tankless water heaters is the gallons per hour rating. The number of gallons per hour that the heater can generate when you raise the temperature of the incoming water determines the flow rate.

Which is the best temperature to heat my incoming underground water?

Well, this is a personal question because the opinion of how hot the water should be may vary from one person to the other. You should also consider that the temperature of the incoming water may different at various times of the year. Even then, a lot of studies have tried to determine what most people find comfortable, on average.

Based on these studies, we can throw in the numbers to help you to narrow down the possibilities. According to research, most people are comfortable washing their hands at near body temperature. You are likely to walk into a shower that spurts water at a temperature of anywhere between 90 to 110 degrees Fahrenheit, primarily depending on whether you prefer a hot or cold shower. Almost everyone agrees that 58 degrees Fahrenheit is too cold for comfortable hand washing leave alone showering.

Exactly how much will a tankless water heater save me?

First of all, there is no dispute that going tankless will indeed save you money. The specific amount, however, depends on a number of factors. The cost of natural gas or propane, for instance, will determine how much money you end up saving. You may have to pay a more if you use lots of hot water. One thing remains clear though; you will never run out of hot water. And the best part is that you are totally in control of the temperature at which your unit heats the water.

How long will my tankless water heater last?

Tankless water heaters will last you long enough to return the value for your money. The type of installation and usage may also have a hand in the life expectancy of your heater. In general, most models on the market will last anywhere between 15 to 25 years. As long as you’re using quality water and the installation is on point, your model shouldn’t have a problem lasting for more than two decades.

There’s a catch though, even the best tankless water heaters require regular maintenance to stand the test of time. You have to clean yours on a regular basis to remove scale deposits and so on. This not only keeps your unit running efficiently, it also helps prevent common instant gas hot water problems. If you have an outdoor gas tankless water heater, you should ensure that you install it in a place where it’s relatively safe from weather elements such as snow and heavy rainfall. Latest models come with a self-regulating internal mechanism that alerts you about any malfunctioning which also helps increase the durability.


Tankless water heaters have their place, now and in the future. With the world shifting to green and sustainable energy, it is almost impossible to imagine that tankless water heater will become obsolete. The best part is the fact that these units not only heat the water relatively fast but also do so without using a lot of energy which means more money in your pocket. And hey, who wouldn’t like to make some savings, especially if it is on recurring bills such as utility? The point that we are trying to make here is that you’re better off getting a tankless water heater, now more than any other time.

As is the case with any home appliances though, you have to shop right. Add the fact that most tankless water heaters don’t come cheap means that you have every reason to exercise due diligence before splurging. After all, you want to be sure that you are investing in a model that will indeed meet your hot water needs for years to come.

We hope that the info provided here has brought you closer to choosing the right model for your situation. Most importantly, we trust that our reviews have helped shed light on why you would opt for one model over the other.

Manufacturers will continue to innovate, bring new models with the latest technology, features, and functionality to market. As they do, we will continue to update our rankings and the information available on this page. Finally, you’re welcome to shoot us any questions you may have regarding tankless water heaters via the form on our contact page, and we will get back to you.

Good luck with your purchase decision and your new tankless water heater!