Best Tankless Water Heaters 2017 – Reviews and Buyer’s Guide

Water heaters are one of those things that we don’t often think about, until something goes wrong. A water heater going out is a big deal; without hot water, you can’t bathe, wash clothes, and properly clean your home. If you are faced with having to replace your water heater, you should definitely consider investing in a tankless water heater.

When it comes to replacing certain household appliances, it can be easy to choose the cheapest replacement option. But when it comes to what is “cheapest,” the initial outlay of purchasing an appliance is not all we should take into account. You should also consider how much a potential appliance may save you in energy usage and thus, cost. A lot of people balk at paying extra for something that claims to be efficient or environment friendly, but this is actually a really short-sighted mentality.

  •    TYPE
  •    FLOW RATE
  •    PRICE
  • 6.6 GPM
  • $$$
  • 6 GPM
  • $$
  • RHEEM RTE-13
  • 4 GPM
  • $$
  • 4 GPM
  • $$$$
  • 9.8 GPM
  • $$$$$

What is a tankless water heater and how does it work?

how a tankless water heater works diagramIt helps to know how a traditional water heater operates. You have a large tank full of water that is kept heated at all times so as to be available whenever you need it. This might seem like a good way of doing things until you really start to think about it. Why keep water heated at all times, even when nobody is using it? Doesn’t this seem like a waste of energy? Certainly, there is a better way.

Sometimes, tankless water heaters are called point-of-use water heaters, which essentially means that water is heated when and where it is needed, or “on demand”. This is opposed to keeping a full tank of water ready and hot at all times. A tankless system still provides instantaneous hot water. When you turn on the tap in a tankless system, the water runs over a heated plate or coil and is then released through the tap.

Basically, with a  tankless water heating system what you get is hot water when you need it, but without the waste involved in keeping water hot at all times. With this system, it heats your water as you need it, which can save  energy and also money in the process.

The pros and cons of a tankless water heater

There are advantages and disadvantages of both tankless and traditional water heaters that should be taken into consideration when choosing which will work best for your needs. However, it should be stated that, overall, when it comes to efficiency, return on investment, and reduced utility bills, tankless water heaters beat the traditional models every time.

Let’s start off with the cons and then we can move on to what to love about tankless water heaters. The biggest complaint about them is that initially, they cost more than a traditional water heater. These systems often need to be installed by a professional and depending on what type of system you choose (gas, electric, portable, indoor, outdoor) the wiring in your home may also need to be updated or a venting system installed.


  • more energy efficient – up to 40% savings
  • instant and endless hot water
  • more precise heating control
  • saves space
  • long service life


  • higher initial cost
  • less powerful systems can only supply water to one outlet at a time
  • gas powered units have special venting requirements

One of the limitations of on demand systems used by tankless water heaters is related to flow rate which is typically measured in gallons per minute (GPM). Because water is heated “on demand” the supply of hot water is restricted by how fast the unit can raise the temperature of the water to the desired level. Less powerful units, therefore, may only be capable of supplying hot water to a single shower or faucet at a time. Flow rates are also affected by the temperature of the water entering the system which is why people living in cold climates require a higher capacity system in order to generate the same flow rates as those produced by less powerful units installed in areas experiencing a warmer climate. Other potential issues with regard to maintenance and inconsistent water temperature have, for the most part, been overcome by recent upgrades in new and improved tankless water heaters.

One of the most salient advantages of a tankless system is that you are not wasting energy to keep 40+ gallons of water heated at all times. This not only saves energy by way of reduced electrical use, it will also save you money on your utility bills. These savings will, over time, help to offset the initial outlay spent in installing said system.

Many tankless water heaters come with a longer warranty and longer expected lifespan. A lot of traditional water heaters are only covered under warranty for about 5 years. Tankless heaters are often under warranty for 10 or more years and their lifespan can be double the traditional model.

How much can I expect to pay?

Generally speaking, the higher the flow rate of the unit in question, the more you can expect to pay. Gas powered systems offer the highest flow rates and so the most expensive units are gas powered, some of which can generate flow rates of up to 10 GPM. To avoid spending more money than necessary, therefore, you should first determine what your minimum flow rate requirements are. This is calculated based on your household’s overall demand for hot water taking into account the local climate and it’s effect on the initial water temperature. An important consideration when calculating demand is the number of simultaneous points of use. So-called “whole house” systems are designed for high demand scenarios such as those common in large family homes. Manufacturers often publish charts to help prospective customers determine the most suitable product for their particular requirements.

You also need to take into account the installation requirements which will vary depending on the type of system to be installed. The venting required by indoor gas powered units often makes them a more expensive proposition although other expenses are sometimes incurred when installing electric powered units too. These usually take the form of certain upgrades to your house’s electrical system. There may be other installation requiremnet

As a rule of thumb, you can expect to pay about twice the amount you’d pay for a traditional water heater. There may also be some associated costs of installation or electrician services that will need to be factored into the cost as well. It is quite hard to really give a good price range since there are so many factors that affect overall cost.

Different types of tankless water heaters

There are three main types of tankless water heater in regular use that we will briefly describe below. These include: portable tankless water heaters, electric tankless water heaters, and gas-powered tankless water heaters.

Portable tankless water heaters

lady showering outdoors using portable tankless water heaterPortable tankless water heaters offer a mobile hot water solution, allowing you to enjoy the benefits of instant hot water anywhere. They are powered by either natural gas or propane and are primarily designed to be used as portable showers. As such most come equipped with a shower head and hose. Portable units are especially popular with campers but can also be used for a variety of other chores around the home. They can be connected to a garden hose for cleaning a car or boat or even washing a pet.

Compact and relatively lightweight, these systems only require a suitable water source. If you have a need  for hot water on demand in a remote location, a portable tankless water heater is a versatile and effective way to have hot water whenever and wherever you need it.

Electric tankless water heaters

An electric tankless water heating system is one that, as the name implies, is run off of traditional electricity. All things considered, electric tankless water heaters are more efficient and cost effective than their gas powered counterparts and have several other advantages as well. For those reasons, electric units are generally the preferred option. This is especially true for point of use applications and for users living in warm climate locations.

It should be noted that electric tankless water heaters are cheaper to buy than their gas-powered counterparts given similar specifications, and installation is also less expensive as well.

With an electric tankless water heater, you have no emissions and it can be run off alternative energy like solar or wind power. They are smaller in size and do not require regular maintenance or special ventilation, which means they can be installed in far more places than is suitable for a gas powered unit.

Although installing an electric water heater is typically cheaper than a gas powered unit, there are sometimes additional expenses which add to the overall cost. In particular, electric tankless water heaters have certain minimum electrical service requirements. Before purchasing, therefore, you should ensure that your household electrical service capacity meets those requirements. If it doesn’t, you will either need to find a suitable alternative or have your electrical service upgraded. If you choose the latter option, you should get a quote from an electrician so it can be factored into your cost analysis.

Gas-powered tankless water heater

If your home is currently connected to a gas line then you may consider installing either a propane or natural gas powered system. While they are generally more expensive to buy and install, gas powered units are slightly cheaper to operate and can generate higher flow rates making them a good choice in colder climates or where water pressure is an issue due to heavy demand.

With a gas-powered tankless water heater, you will need professional installation as the system must have proper ventilation. These systems tend to have the highest flow rates, giving you the best water pressure possible. These systems do require regular, annual maintenance, however, to ensure that they are operating safely and efficiently.

It should be noted that while gas powered units are slightly cheaper to operate, they are less efficient compared to electric water heaters and predicted increases in gas prices will eventually negate their current cost advantage. Furthermore, while it’s true that gas powered units can generate higher flow rates for any given temperature rise compared to electric systems, a properly sized electric unit is generally equal to the task in terms of flow rate across a broad range of end user requirements.

What size tankless water heater do I need?

Another common question when it comes to choosing the best tankless water heater has to do with the appropriate system size. How do you know how big a system you need?

In simple terms, tankless water heater performance is evaluated on the basis of flow rate, measured in gallons per minute. The most important factor affecting flow rate is the difference between the desired temperature and the temperature of the ground water entering the unit (referred to as temperature rise).

Choosing a suitable unit involves establishing your required or peak flow rate based on hot water consumption patterns and then matching this with a suitably rated unit, taking into account the required temperature rise.

It’s important to remember that flow rates are relative and that stated flow rates generally reflect best case scenarios. Actual flow rates will vary depending on circumstances.

So basically, you need a system (or multiple systems) that has the right flow rate for your water usage needs. To determine what your needed flow rate is, you will need to consider how many different items you will be running off said system, considering those things that are run concurrently. After you have your list, you can find their individual flow rates and add these up.

The number you are left with is going to be the flow rate you should look for to meet your household demands.

You will also want to determine how hot you want the water to be. For most common uses, people want hot water that ranges between 105-115°. This figure combined with the temperature of the ground water determines the required temperature rise which, in turn, determines the flow rate of the particular unit in question.

You can easily find charts online that give you a rundown on average flow rates and desired temperatures for many basic household appliances that can make it much easier to determine your overall requirements.


installing a tankless water heaterAs noted above, unless you really know your way around a tool box and know the ins and outs of installing water  lines and electrical systems, the installation of a tankless water system is something that is probably best left to the professionals. Yes, having a professional install your system will add to the cost, but it will also ensure that your system is safely and correctly installed.

Even if you have a professional install your system, it is still helpful to understand the basic process involved.

The old water heater will need to be removed, which will also involve turning off all water, gas, and power for safety. New gas or electrical lines, if needed, will then be installed. Once you have this taken care of, it is time to install your new water heater and connect it to your water system.

If you have opted for a gas-powered unit, this is the point at which ventilation would need to be installed. Once you have all the bits and pieces tightened and everything is in place, you can turn on your new water heater and check it out.

Before carrying out any installation work make sure you understand the terms and conditions of your unit’s warranty. In some cases installation must be undertaken by a licensed professional.

Tankless Water Heater Reviews

What follows is a brief review of some of the most popular water heaters from each category: electric, gas, and portable. We list their salient features, and touch on the pros and cons associated with each model so as to help make the selection process a bit easier.

1. EcoSmart ECO 27 Electric Tankless Water Heater

EcoSmart is a trusted and reputable brand that is known for making a range of environment-friendly appliances, pest control products, and more. This is an excellent choice for those who want a tankless heater that is efficient and has a low environmental impact and carbon footprint. This is an electric tankless system that features:

  • High flow rates perfect for cold climates
  • Save up to 50% on heating costs
  • Digital temperature control
  • Durable design

The system is well machined and finely constructed to be durable and stand the test of time. With the digital temperature control system, you can easily manage the temperature of the heated water. It also boasts a self-modulating flow sensor that helps to regulate the amount of heat needed.

The biggest complaint associated with this model is that in winter, in very severe climates, it can be difficult for the system to keep up. This means that sometimes you will get hot water, but at a reduced flow rate, which can be frustrating… Read full review

2. Rheem RTE 13 Electric Tankless Water Heater – best budget model

Rheem is another trusted manufacturer of water heaters and other quality home appliances. This system boasts easy installation without a lot of need for retrofitting as it is mounted via a standard 1/2” water connection. It has a maximum flow rate of 4 GPM (gallons per minute) making it perfectly suited for warmer climates or low to medium flow rate requirements. It has an on-unit control system with LED indicators that makes it easy to choose and monitor your water temperature. The system boasts:

  • Brass/copper heat exchanger for durability
  • On-unit temperature control
  • Compact design

Once again, if you are looking for a whole house system, this unit is unlikely to be your first choice. It is, however, an ideal water heating solution for smaller households. Please be aware this unit has specific electrical service requirements and so before purchasing you should check to see if your existing configuraion is compatible or not, and, if not, get a quote on how much it will cost to make the necessary changes…Read full review

3. Stiebel Eltron Tempra 24 Plus Electric Tankless Whole House Water Heater – best overall

Stiebel Eltron is a trusted and well-known brand that makes a range of household appliances, including a variety of tankless water heaters. This is an excellent, comprehensive heating system that can easily supply your whole home’s hot water needs with ease. This is a higher end model than the ones we have already reviewed, and the system features:

  • Digital temperature control
  • Single-flow sensor design
  • Advanced flow control
  • Heavy duty electronics

This is designed with German engineering expertise and is a very well received model. Of course, this high standard is reflected in the price tag but, all things considered, this is still a reasonably priced unit. To ensure trouble free installation, you are advised to check the electrical service requirements of this model for compatibility with your existing configuration…Read full review

4. Takagi T-KJr2-IN-NG Indoor Tankless Gas Water Heater

Takagi is a trusted brand that makes a range of high-quality household appliance and other products, including some very well designed, high-quality, gas-powered tankless water heaters. Their Indoor Tankless system is an excellent choice for those whose homes run on natural gas. It boasts one of the highest flow rates of any tankless heater, making it perfectly suited for homes that are heavy on their water usage. The heater boasts:

  • 140,000 BTU
  • 6.6 GPM flow rate
  • Advanced temperature control system

This unit can be tricky to install depending on your existing set up and so is best left to the experts. Moreover, the warranty becomes void if it is intstalled by anyone other than a licenced professional. You may also need to purchase additional hardware such as an exhaust pipe to get the unit up and running…Read full review

5. Rheem RTG-64XLN 6.4 GPM Low NOx Outdoor Tankless Gas Water Heater

This is another quality unit from Rheem, one of the most trusted and popular tankless water heater manufacturers. Unlike the previous model, this is a natural gas powered unit and is designed to be installed outdoors.  Outdoor installation has certain advantages including easier ventilation but it may not be a good choice in locations subject to severe winter temperatures. Some notable features of this unit include:

  • 6.4 GPM flow rate
  • UMC-117 control and thermostat included
  • Low nitric oxide (NOx) emissions
  • Next generation burner technology

This is a quality unit at a reasonable price and as such represents excellent value for money. Users have high praise for its ability to heat water quickly and maintain it at a constant temperature. It also features a .26 GPM minimum flow rate which is claimed as an industry best. Being an outdoor model makes it an especially good solution for an outdoor shower. As always, correct sizing is crucial to gaining a high level of customer satisfaction from this or any other unit…Read full review

6. Rinnai RUC98iN Ultra Series Natural Gas Tankless Water Heater – best gas powered unit

Rinnai is a popular maker of tankless water heaters and is well known for their quality and good design. This model is a natural gas-powered heater that can be installed inside the home with proper ventilation. It is 95% efficient, showing you just how much energy you save compared to a traditional heater. The Ultra Series also features:

  • 15,200 BTU
  • 12-year warranty
  • High flow rate

This is another good, whole-house option for those who have heavy water usage needs and/or those living in colder climates. Like the other gas models we have reviewed, the biggest complaint about this model is that it is more expensive than its electric counterparts but the extra expense for a high capacity gas powered unit such as this is definitely worthwhile and even necessary in some situations…Read full review

7. Eccotemp L10 Portable Outdoor Tankless Water Heater

This is another quality, versatile, and travel friendly portable water heater from the trusted brand, Eccotemp. Portable water heaters are a great way to take hot water camping, to a cabin that perhaps lacks modern plumbing, or for use outside. This heater features:

  • CSA approved gas regulator
  • Stainless steel rain cap
  • 74,500 BTU

The 2.64 GPM flow rating is better than average for a portable unit but still low when compared to indoor systems so you should manage your expectations accordingly. And, of course, the actual flow rate (as opposed to the advertised flow rate) will vary depending on local conditions. As with all tankless water heaters, and portable units in particular, there is a trade off between flow rates and water temperature. Overall, however, this unit performs well and is easy to set up and operate.

8. Camp Chef HWD5 Triton Hot Water Heater

This hot water heater is another great value and affordable solution made by Camp Chef. This is a great model for use in camping or other remote settings, giving you on demand hot water when and where you need it. Portable units such as this are also used for washing pets, cars and boats and can even be used to fill a paddling pool. The unit can be connected to a standard garden hose and includes the following features:

  • 1.5 GPM flow rate
  • 4 flow settings for shower head
  • Steel construction for durability
  • Automatic ignition

The design of this water heater is well thought out. The included brackets and free standing base give you a range of options for positioning the unit. It also features an 8′ shower hose and a convenient carry handle which folds down for storage. In terms of durability, however, there is some room for improvement but given the price, it is unrealistic to expect a bulletproof product.


If you are looking to replace your current water heater or are simply looking for a cheaper and more energy efficient water heating solution, it makes a lot of sense to consider a tankless heating system. With a tankless water heater, you reduce your energy usage and can dramatically cut your utility costs, without sacrificing hot water or water pressure. Furthermore, after installing a tankless system you can rest assured you will never run out of hot water again.

If you are looking to replace your current water heater,  or simply want a more efficient and cheaper hot water heating solution, it makes a lot of sense to consider a tankless heating system. With a tankless water heater, you reduce your energy usage and can dramatically cut your utility bills, without sacrificing hot water or water pressure. Whether you get a gas, or electric-powered model will depend on your requirements, as well as how your home is currently powered. These appliances will pay for themselves over time, providing your family with the hot water it needs, without all the waste.

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