Best Tankless Water Heaters – Buying Guide with Best Heater Reviews

We all are well aware of the fact that water is the most important element of life. Every being on this planet require water in some of the other form. Let it be drinking, taking a bath, washing vegetables, doing laundries, wiping the car or just any other need. 

A tank water heater consumes a lot of valuable space in a house. And if your house is small, you might be crying after installing a tank water heater to use the hot water. But ever since the invention of tankless water heater, the things have changed for people. 

Now, you just need to turn on the tap and hot water will start flowing. You can take a hot shower or wash utensils with hot water in fall season. 

With some really awesome heating performance, instant heating capabilities and endless hot water supply, tankless water heaters are becoming way too popular. 

Let us go through this complete buying guide and find the methods that can help you buy best tankless water heaters at cost effective price without compromising with quality. Apart from that, you can scroll through some of top-performing tankless heaters and make your buying decision according to features and customer reviews listed here.

Best Tankless Water Heater Reviews
Best Tankless Water Heater Reviews, Buying Guides, Specifications, Top Brands & more

13 Best-Selling Tankless Water Heaters – Comparison Chart

If you are here, you might be searching for some of the best tankless water heaters at cost-effective price. So, we have listed down 13 best water heaters without a tank that can perform really well at affordable budget.

Include 13 Water Heaters – best Selling

Best Tankless Water Heaters Reviews

Helping our readers to find the best appliance is our ultimate goal. This is why we have reviewed some of the best instant water heaters in the market in 2019. A brief comparison explaining about the features and what customers says have been made among these top-rated water heaters. 

Rheem RTEX-13 240V Heating Chamber Residential Heater

If we consider the number of sales, this is the best-selling residential tankless water heater on Amazon. If I have to recommend buying a water heater without a tank to someone, Rheem RTEX-13 240V Heating Chamber Residential Heater would be my first recommendation. 

  • Perfect for Studio Apartments: It is the best appliance to have installed in a small bathroom. It has a flow rate of 4 gallons per minute. You can get hot water within few minutes once the device is turned on.
  • Easy to Operate Digital Controls: As all the digital temperature settings are given externally, temperature control becomes easier with this device. The current temperature is visible on the small screen given at the front. You can increase the temperature by 1° Celsius at a time. 
  • Short Waiting Time for Hot Water: The hot water starts flowing in just 15 seconds once you turn it on. Also, the temperature stays stable while you are using the water heated by this heater. In short, you don’t have to wait much for hot water once it has been installed.
  • Easy Installation: The multiple stranded wires make the connection much easier. It takes mere one hour to hook it by yourself. But make sure you follow the instructions before carrying out the installation.


  • Cost-Effective Price
  • More Energy Savings & Less Energy Costs
  • It is compact and weighs just 4 pounds, saving a lot of space.
  • The water temperature is maintained for a long time even if this tankless heater is turned off.
  • The installation process is easy to carry out.


  • It is not suited for a big house or bathroom.
  • It supports only one faucet at a time.Rheem RTEX-13 240V Heating Chamber Residential Heater Price

EcoSmart ECO 27 Electric Instant Hot Water System

Another awesome water heating system that I have recommended to my friend is EcoSmart ECO 27 Electric Instant Hot Water System. The compact size of this appliance makes it easy to install anywhere, let it be kitchen, bathroom or your washroom. 

  • Temperature Range: You can easily set a wide temperature range on this device i.e. 80° F to 140°F. As it’s a small water heater, it is capable of heating 3 gallons of water flow per minute. It’s ideal to use in places with sub-tropical climate. 
  • Two Shower Support: It maintains a steady 3gpm flow rate even in cold weather conditions. This can reach to 6gpm in warm areas. That’s why it supports two showers simultaneously. As the machine is turned on, you can get the hot water supply within minutes and the water stay hot even after a long period of time when the device is turned off.
  • Excellent Quality: The Copper and stainless-steel components in the heater ensure high corrosion resistivity and provide effective heating mechanism. All its heating components are readily available, just in case any part malfunctions when warranty expires.
  • Energy Efficient: The self-modulating technology powered appliance only draws energy when it is needed by you. It can save up to 50% of heating costs in long run.


  • It is ideal fir for bathroom, kitchen and washroom all-together.
  • You get unlimited water supply.
  • Self-modulated technology to save on energy spent.
  • Easily adjustable temperature control buttons.
  • You can save at least 12 cubic feet space after installation.


  • Sometimes, you may find fluctuations in temperature.
  • Unable to produce hot water at high flow rate.EcoSmart ECO 27 Electric Instant Hot Water System Price

Rinnai V75IP 7.5 GPM Indoor Low NOx Tankless Propane Water Heater

One of the world’s renowned brand Rinnai manufactures the best tankless water heaters that works on propane as major power source. It requires venting for indoor installation. One of the best equipment manufactured by Rinnai for residential houses is Rinnai V75IP 7.5 GPM Indoor Low NOx Tankless Propane Water Heater.

  • Powerful Built: It delivers a maximum BTU of 180000 and the flow rate reaches as high as 7.5 gallons per minute. It can easily support up to two bathrooms at a time. 
  • Easy Installation: If you are well versed with copper soldering skills and know a bit plumbing, you can install it by your own. Otherwise, you may require a professional aid. It offers 10-year warranty for heat exchanger and 5-year warranty for other parts.
  • Endless Hot Water: You need not to wait for more than 10 minutes to get hot water. The only glitch here is that, it is bit noisy when it warms the water. This is due to propane power design.
  • Low NOX Design: You need to install the venting facilities in case you are installing it indoors. This ensures that the wasted gas is sent out. The low NOx design ensures the reduction in emissions of carbon dioxide (CO2).


  • It is a powerful machine with strong built.
  • Additional controller features are available.
  • Offers 10-year warranty for heat exchanger and 5-years for other parts.
  • Capable of handling two-showers simultaneously.
  • Ideal for mid-sized family.


  • Makes noise while working.
  • You need proper venting of you are installing it indoors.Rinnai V75IP 7.5 GPM Price

Rinnai RUC80iN Ultra Series Tankless Heater

Rinnai RUC80iN Ultra Series Tankless Heater is another solid machine from Rinnai that has the best reviews on as well. Apart from using it as a residential heater, it can also be used as a commercial tankless water heater. 

  • High Temperature Range: For residential use, it offers a high temperature range from 98°F to 140°F. But if it is used as a commercial water heater then the temperature can go up to 185°F. You need to buy the commercial remote separately.
  • Heavy Water Flow Rate: It offers a water flow rate of 9.8gpm which is relatively high as compared to general residential water heaters. It can easily be used to supply hot water to 4 bathrooms. You get constant water flow.
  • Highly Efficient: The power required by this device ranges from 152000 to 199000 BTU per hour. It delivers a thermal efficiency of 0.95. Therefore, it is powerful enough to be used in houses with big families or commercial stores. It saves you big heating costs every month.
  • 2 Venting Options: It offers two types of venting options – one is concentric PVC and the other is twin pipe. You can choose any of the method as per your requirement. The heating is really fast and takes just 20 seconds.


  • Unlike most of the propane heaters, it doesn’t make noise.
  • Offers two venting options.
  • High flow rate.
  • Works in both commercial and residential sector.
  • Highly energy efficient.
  • You just need 2-watt consumption to keep it up and running.


  • Professional aid is required for installation.
  • You have to buy commercial remote to change temperatures for commercial use.Rinnai RUC80iN Ultra Series Tankless Heater Price

Takagi T-KJr2-IN-LP Indoor Type Tankless Water Heater

If I talk about a nicely built tankless water heating machine, then Takagi T-KJr2-IN-LP Indoor Type is one that I would recommend for indoor purposes. It is the lightest and most compact heaters available in Takagi product line and best suited for studio apartments.

  • Awesome Flow Rate: It offers an extraordinary flow rate of 6.6gpm in cold regions at a cost-effective price range. This rate can even drop 3-5 gallons if there is extreme cold.
  • High Temperature Range: It offers temperature range up to 150°F. The power input required per hour is around 140000 BTU, producing a thermal efficiency of 81%. It is not powerful enough for a whole big house, but small or mid-sized families can still use it.
  • Highly Efficient: This is a propane type machine and needs venting too. Though the upfront cost may be little higher, but in long term, the cost can be reduced significantly as it saves energy.
  • Long Service Life: Without a tank, the heater only turns on when hot water is required. Therefore, no corrosion occurs. Therefore, you can use it for long run. Moreover, you have a good cost overall.


  • It is compact in design and light in weight.
  • Digital remote is available along with the piece.
  • Suitable for middle size and small house
  • Offers a large temperature range.


  • It is noisy.
  • Venting is required if you don’t have any open vents.Takagi T-KJr2-IN-LP Price

Stiebel Eltron Tempra Plus 24 kW Tankless Water Heater

One of the finest instant heat water heaters in this list is Stiebel Eltron Tempra Plus 24 kW Tankless Water Heater. It needs 240v power to operate under ideal conditions. Though it is small in size, it is capable enough to be used for commercial purposes. 

  • 5gpm Water Flow Rate: This unit is capable of providing 5 gallons of water per minute. The water is heated up to 54°F at water flow rate of 3gpm. It operates in areas where supplied water is under 45°F. It can be utilized in two bathrooms simultaneously. 
  • Technically Advanced Design: It is equipped with self-modulating technology to heat water only when it is required by you. The advanced flow control system controls the constant temperature along with water pressure in different flow levels. 
  • Full Power Modulation: It supports total power modulation. 99% energy efficiency ensures that no water is wasted during the process. Moreover, it is designed with high-level electronic parts and is equipped with reliable body built.


  • It operates without making noise.
  • It doesn’t have any mechanical switches.
  • This model is highly efficient and energy saving.
  • The compact design saves a lot of space.
  • It is used widely for commercial purposes and for residents as well.
  • It is fully power modulated.


  • It requires heavy duty wiring to operate at 240v power.
  • No more heating elements can be installed inside.Stiebel Eltron Tempra Plus 24 kW Price

Marey ECO150 220V/240V-14.6kW Tankless Water Heater with Smart Technology

It is another electric tankless water heater used under 220v or 240v power supply with 14.6Kw. It is designed using smart technology making Marey ECO150 220V/240V-14.6kW Tankless Water Heater with Smart Technology the best energy-saving electric water heater without tank.

  • Corrosion Resistance Element: It is a German-designed electric tankless heater that has a patented heating element made up of stainless-steel water channel. Therefore, it is corrosion resistant and eliminates the hard water easily. 
  • Easy to Operate: You can adjust the temperature easily. It has an LCD panel to display the temperature. It delivers a water flow rate of 2.5gpm. 
  • Stylish Compact Shape: The small and compact design ensures that it can be installed anywhere you want. It supports two sinks at the same time. It operates at a voltage of 220v to 240v and 70amp current.
  • Easy to Install: It is capable of offering hot water to you constantly without a pause. It weighs just 10.1 pounds and can be used for indoor as well as outdoor purposes. 


  • It consumes less energy and ensure cost-savings.
  • Corrosion resistant component is installed. 
  • It is light weight and designed with compactness.
  • It can be installed easily and provide steady hot water.
  • Activate by pressure ranging from 5 to 85 PSI.


  • It cannot be used in a big house.Marey ECO150 220V_240V-14.6kW Cost

Rheem RTG-95XLN 9.5 GPM Low NOx Outdoor Tankless Natural Gas Water Heater

It is a gas-based tankless water heater that is best for commercial purposes. Though it can be utilized by residential houses, but commercials can found better applications of Rheem RTG-95XLN 9.5 GPM Low NOx Outdoor Tankless Natural Gas Water Heater

  • Large Flow Rate: It offers an awesome flow rate of up to 9.5 gallons per minute. It can be utilized in at least four bathrooms easily. Once it gets heated up, you get hot water supply flawlessly. You will hardly run out of water while bathing if you are using it.
  • No venting Kits Required: Both propane and natural gas can be utilized for heating purposes. If you don’t have gas line, you can definitely use propane as option. As it is installed outdoor, no venting is required. It also saves energy to large extent.
  • High Thermal Efficiency: Its thermal efficiency is really high i.e. up to 94%. Together with low NOx design, it emits less Carbon dioxide (CO2) and saves your heating cost to large extent. 
  • Remote Control: The smart home technology – EcoNet that is utilized by this gas tankless water heater supports remote that can be operated with app. You can easily turn the machine on and off and adjust the temperatures as per your needs.


  • Natural gas and propane, both can be used for heating purposes.
  • The controls can be accessed via app.
  • It is highly energy efficient.
  • Its dual stainless-steel heat exchangers offer option to connect both vents when hot water is needed in large amount.
  • It offers 10-year warranty on heating parts.


  • It requires a professional to install this appliance.Rheem RTG-95XLN 9.5 GPM Price

Noritz NRC661-DV-NG Indoor Condensing Direct Tankless Hot Water Heater

Though it is of condensing type, it saves a lot of money. Noritz NRC661-DV-NG Indoor Condensing Direct Tankless Hot Water Heater uses more gas and waste extra energy while heating.

  • Large Flow Rate: It offers a flow rate of 0.5gpm to 6.5gpm. It can easily support two bathrooms at same point of time. It works cleanly without making any sound.
  • Highly Efficient Machine: The gas consumption rate is between 15000 and 120000 BTU every hour while the thermal efficiency reaches to 93%. Its low NOx design try to save energy losses and heating costs.
  • Double Vents: One of the heat exchangers is made up from stainless-steel while the other one is made from copper. It is vented with 40PVC pipe and fittings. It also offers up to 12 years of warranty n all heating parts.
  • Freeze Protection System: This protection protects the machine from getting frozen in very cold climate. It senses the cold weather automatically, beside giving you ability to control the temperature with remote. But you’ve to buy the remote separately. 


  • Freeze Protection System
  • Compact Design
  • Dual Venting options
  • Operates without making sound
  • High Energy efficiency


  • Cold water sandwich.Noritz NRC661-DV-NG Water Heater Amazon Price

What’s a Tankless Water Heater – A Brief Introduction

A tankless water heater is a heating machine which is used to heat the water constantly for residential, commercial, outdoor travelling, camping or any other purpose. Most of us who are on this page must be knowing about water heaters that are commonly called geysers. These store water in a separate tank and this is the reason why they are bulky. 

A quality heater will heat water within seconds and delivers hot water constantly as soon as the tap is opened. According to a research conducted in 10345 residential and commercial properties, a tankless heating system is capable of saving around 22% operating cost every year. 

If you have a large family and have multiple bathrooms or faucets, going with a water heater capable of offering larger flow rate is recommended. Tankless water heaters surely remove the headaches and problems that come along with water heaters having tanks. This is the reason why they are becoming popular in most of the parts of the world as compared to geysers.

How to Define a Good Quality Water Heater?

As compared to a tank type water heater, the tankless type water heater comes with excellent heating performance. Not only this, it comes with compact design that can save a good space in your bathroom or anywhere else you wish to install tankless water heater. 

When you look for a heating system without tank, you should always look for a compact and better performing one like those we have listed in the list. All of them are awesomely built and have good efficiency saving good amount of energy.

When we look into this industry, there are a number of water heaters that are designed for various purposes. These efficient water heating devices are designed on basis of area, family, type of use, point of use and considering other factors. 

Therefore, you need to look at your purpose of buying the heaters before coming into any decision. The one that suits your need perfectly should be your choice ideally. 

The Working of Tankless Water Heating System

A water heater without a tank is capable of heating water through electric elements. The best part is that, in most of the cases, the temperature control, flow rate, power and other important controls stay in your hands. So, you can get the ideal temperature for your showering needs. 

You will be amazed to learn that almost every instant hot water heater is equipped with self-modulation technology. It gets activated automatically at certain pressure level and activates heat only when hot water is needed. Ut is also termed as on-demand heating machine or instant hot water machine.How does a Tankless Water Heater Work

Top Features that you will Find in Best-Quality Tankless Water Heaters

If you are planning to buy a best-quality water heating appliance to get the supply of hot water flawlessly at your home or commercial property, then you should consider looking at following feature before coming to the buying decision.

Instant/Quick Hot Water Supply

A tankless hot water machine is capable of heating water within few seconds. It doesn’t store cold water inside, but whenever you need hot water, it delivers its flawlessly. The hot water supply is endless once you turn on the machine. This ensures that you never run out of hot water at odd situations. These small compact machines find their applications in commercial spaces like hospitals, restaurants and even at residential complexes.

Energy Efficiency

The instant heat water system eliminates the wastage of heat energy that often happens in case of tank water heaters. As no water is stored in the tank, there is no extra energy loss of unused hot water. It provides instant heating and is capable of saving around 10-30 percent of energy and electricity every year. You will realize this in long run.

Environment Safe and Environment-Friendly

All heating machines must be safe, and this should be one of the primary factors to make a buying decision. The manufacturers must give guarantee of safe working of the machine that they’ve designed keeping the safety measures in mind. The safety measures should include overheating protection, leakage protection, digital controls and other measures.

Small and Compact in Size

As the storage tank and any kind of insulation are not required, the hot boilers are normally light in weight and compact in design. These can easily be accommodated in small spaces and commercial stores easily. Some of them are as small as the size of standard magazine.

Apart from their compact shape, the compact water heater is designed sleek in built, and available in different designs for those who are bit choosy.

Stabilize Water Temperature

The temperature of tankless water heater should be kept stable and there should be advanced mechanism to control it manually so that you can use hot water for different purposes flawlessly.

Long Life Run

The quality of these on-demand water heaters, cold water is heated without passing it through the heating element. This is the reason why no limescale is left on the internal parts and this type of water heater hardly needs any maintenance.

The temperature rise during the heating process is relatively low if compared with tank type water heaters and thus, it does little or no damage to machine. This is why a water heater without tank or instant hot water heater can last even for 20 years. 15 years is the average lifespan of these heaters.

Tankless Water Heater vs. Tank Type Water Heater: Full-On Comparison 

The instantaneous hot water system and tank water heater are two types of heating machines that are used on a frequent basis in our daily life. The conventional model of water heater is tank type in which the water is stored in tank and you have to wait for long for water to be heated up. It makes use of large capacity tank to solve the contradiction between a small heating pressure and large using capacity. You have to take an estimate of daily hot water use when you choose tank type water heater. 

The hot water heating system is the modern way of heating the water. It heats the water without storing the cold water and saves energy as well. These types of water heating systems are specifically designed to be compact and energy efficient.

Both of them have their own advantages and disadvantages. So, we’ve put together a detailed comparison among the two that will help you in determining the best water heater for your requirements at given point of time.


The compact water heater is small in built and is lightweight too. Some of them can even weigh as light as 10 pounds. These can be used if you need them while travelling. They are available in colorful design and multiple shapes. So, you can choose among different options and varieties available in the market.

The water heaters with tanks are large and bulky because they heat the cold water stored in their tank. All of these water heaters with tank are designed either in round or in square shape. So, you have a very limited choices if it comes to the appearance.


The cost of tank-based water heater is greatly influenced by the capacity of water it can hold. The larger the capacity, the more expensive it would be to buy.

The tankless water heater price may vary according to its type and performance. Of course, the portable water heaters are much cheaper than the ones that are to be installed in houses or your commercial property.


The heating machine without tank has requirement on water pressure, electricity, circuit or pipelines.

A tank-based water heater has requirement on the wall load bearing, but not on power.


A tankless hot water heater will constantly provide you’re the running hot water and is quite convenient to be used. It not only saves water, but also electricity to a large extent. A no waiting time is needed on heating the cold water, it even saves most of your time. The temperature rise is not stable in winters.

A tank-based water heater heats the water slowly and you might have to wait for longer time. There is also a trouble of running out of hot water while you are bathing, and you again need to wait for the water to get hot. Also, the unused hot water is stored in the tank which gets cool in sometime, therefore wasting a large sum of electricity. 


A tankless water heater will only heat the water when you will need it. Therefore, no heat loss and circulate heat situation happens in this case. It adds to the efficiency of the appliance. As water is heated directly, no limescale is left inside the machine. Thus, it requires less maintenance.

The tank water heater stores the water in a storage tank. While using it for a long period of time, a lot of limescale is left in the water tank and pipeline. It requires regular maintenance and cleaning.What is a Tankless Water Heater

Various Types of Tankless Hot Water Heaters

There are a number of water heaters available in the market to serve different purposes. It is up to you, what type of requirement you have and how you want to use the tankless water heater.

A. Usage

If we classify them depending on the usage, there are different types of water heaters namely – whole house water heater, point of use instant heater, RV use heater, commercial heating system and instant hot water system for camper.

1. Whole House Tankless Water Heaters

It generally refers to a machine that is powerful enough to support heating needs of multiple bathrooms and faucets simultaneously. The flow rate of these types of heaters is large while the power requirement is also high for operation. Moreover, they are more expensive as compared to other types of heaters that can be installed in home. We have prepared a list of some of the best whole house water heaters with their reviews. You can check them before making your buying decision. 

2. Point of Use Tankless Water Heater

This type is commonly used in small studios or support one faucet or bathroom at a time. They are less powerful and have a lesser flow rate. These are relatively smaller in design and can be easily installed under the sink. You can check out more details by going through these best Point of Use Heating System reviews.

3. RV (Recreational Vehicle) Tankless Water Heaters

These types of heaters are commonly used for outing or camping purpose. As they are tankless, you can install them in your vehicle and can be used in your travel. Most of the RV heaters are of electric type of gas (majorly propane) type for convenient usage. Go through these best RV Use Heater Reviews to learn more about them.

4. Commercial Tankless Water Heaters

The commercial water heaters without a tank are heating machines that are widely used in hospital, hotels, spas, schools or any big commercial space. The flow rate is quite large, and they operate in high capacity and power. They are ideal for places which need constant hot water supply. You can even cascade a number of them together if one single unit is not powerful enough to meet the requirements. Check out the best commercial water heater reviews and explore more about them. 

5. Tankless Water Heater for Camper

It is very similar to RV type of water heaters, but they are lighter in weight and very compact in design. You can carry them along and install them easily wherever you go. Check out some of the best heating machines for a camper

B. Size

Depending on the size there are small and portable heaters. As the size of these tankless water heaters is small, we hardly talk about the large ones.

1. Small Tankless Water Heater

A small instant hot water system doesn’t only mean that it would be small in design, but it will also have a small flow rate. Some of the tankless heaters are designed in compact shape yet can provide hot water for a complete house. These small units are commonly used in middle-sized house, studios, garage or cabins. Check out some of the best small water heaters and grasp more information.

2. Portable Tankless Water Heater

We can go by name. These are the portable units that are lighter enough to be carried along when you travel outdoor. These types of water heaters generally found their applications if you are travelling or camping. The flow rate is small, and they can support only a single bathroom. You can check out the best portable heater reviews to learn more. 

C. Installation

Depending upon the installation spots, we divide the tankless water heaters into two categories – indoor and outdoor. 

Indoor Tankless Water Heater

We generally install the indoor water heaters inside the house or your RV. The major advantage is that it minimizes the risk of damage to the machine from complicated weather conditions outside your home. But, you need to install the venting facilities for gas type heaters. This may cost you a bit higher. To learn more, you can go through the best indoor hot water heaters reviews.

Outdoor Tankless Water Heater

Though the ventilation facilities are not needed for outdoor heaters, you need to spend more money on getting them protection against natural damage caused due to poor weather conditions. There many installation tips that need to be followed before installing the outdoor type heaters. You can check these recommendations in our best outdoor water heater reviews.

D. Power

Depending upon the power, we generally classify the hot water system into three different types – natural gas, propane type and electric type. Here is the detailed comparison of all three. 

Gas or Electric Type Tankless Water Heaters

Electric vs. Gas Tankless Water HeatersThe gas type heater is commonly powered by natural gas or propane while the electric tankless water heaters uses electricity for its operation. Let us explore the differences between them based on several factors.

  • Power: The gas water heaters are more powerful as compared to electric type as they can easily support multiple bathrooms or faucets at the same point of time and are frequently used as commercial or whole house water heaters. The electric instant water heaters are less powerful and can mostly support a single bathroom or faucet simultaneously. These are designed for small studios or single room houses.
  • Working Noise: Gas type water heaters make more noise as compared to electric ones because the working principle of natural gas tankless water heater requires gas to burn. The electric type of hot water heaters generally doesn’t make any noise. 
  • Energy Efficiency: It has been tested that the natural gas tankless water heater is 3 times more efficient than the electric ones. Over 90% of energy is used without getting wasted during the heating process.
  • Price: Depending on the price, the gas tankless water heaters are more expensive and require high usage cost as compared to electric one. The electric water heaters don’t need any venting facilities to be installed before usage. So, this saves a lot of money upfront. Installing gas heaters is also a difficult job and you may require professional help to do the things beyond your capabilities. Both installation and venting costs sum up huge money. However, the gas type saves more money than electric one in long run. 
  • Environment-Friendly: As natural gas is regarded as clean and green source, it does less harm to the environment, but let out carbon dioxide emissions. On other hand, the electric type water heaters don’t emit greenhouse gases.
  • Maintenance: Both these heaters heat the water directly and therefore don’t require excess of maintenance as in case of water heaters with tank. However, if we compare both machines, the electric one needs more maintenance as compared to the gas one. The maintenance cost is paid from your budget.
  • Temperature Stability: The rise in water temperature may be influenced by the cold climate or altitude of your using spots. When you use them in cold weather conditions or at high altitude, the temperature of electric tankless water heaters get dropped and so is the flow rate. In case of natural gas water heaters, the temperature remains stable. 

Overall, the natural gas heaters are cheaper in use, powerfully built and suitable for any climate conditions. The upfront cost might be high in their case and you must install them in an airy place instead of bathroom. Also, the water pressure must be large enough for proper ignition.

An electric tankless water heater is comparatively affordable and environment-friendly too. But as the flow rate and power required is low, it is not suited for whole house of commercial purpose. It can be the replacement for solar powered heaters. 

Tankless Water Heater Buying Guides

Tankless Water Heater Buying GuideWhile choosing the best hot water heating system, you need to be sure about different types of factors that you require to check before making the buying decision. A quality instant water heating system can be a great helper for your daily hot water requirement needs. So, you need to make the best choice before installing just any tankless water heater at your home. 

Let us check some of the major factors which you should consider before buying the water heater without a tank for your house. 

1. Flow Rate

As no tank is installed in the heating machine, you should never worry about the capacity, but you still have to estimate the daily hot water requirement. You also need to decide the purpose you will be using the hot water coming from the water heating appliance. Then only you can choose a suitable flow rate depending on your requirements and applications of use.

For example – a dishwasher requires 1-2.5 gallons of water per minute to wash the utensils, bathroom faucet needs 1.5gpm water while a kitchen faucet requires 3-5gpm of water. For two bathrooms, the hot water need in winters may reach to 6gpm. 

2. Power Source

We have also introduced this before. There are three types of water heaters depending on power source – propane tankless water heaters, natural gas type and the electric types. If you are looking to use them for whole house supporting two-three showers at a time, then gas or propane tankless hot water heaters is what you require. But if you want single shower at a time or lives in studio apartment, then you can go for electric type. 

3. Home Location

The location of your home is also an important factor that must not be overlooked while choosing a water heater. If you are living in warm areas, you can choose the machine as per the flow rate. But if you reside in cold areas and the climate is going to have a major impact on flow rate of temperature rise then you need to buy the tankless heaters with higher flow rate as the flow rate might drop around 2gpm in extreme cold climates. 

4. Energy Efficiency

If we talk about the efficiency, then gas or propane type of heaters ate the most efficient ones in long run. The thermal efficiency reaches up to 90% for some of the models. The electric tankless water heaters are also able to save up to 60% of energy in long run.

Some of the gas models are equipped with condensing technology that can recover the unused energy in non-condensing types. This greatly improves the efficiency and reduces the emission of greenhouse gases. 

5. Installation Costs

The installation process of a tankless hot water system is simple and straight forward, but always have a special requirement of pipes, pressure and lines. If you are looking to replace the tank water heater with a new tankless one, then you might have to change the entire wire system if it is inefficient with the old one. For professional installation, you have to pay a hefty amount as well.

6. Indoor and Outdoor Installation

If there is a shortage of space in your home, then you can always choose the outdoor type. This type is installed outside your home and have no venting needs. But in this case, you have to provide protection to your appliance against all the odd weather conditions that might damage it adversely. 

7. Price

The tankless water heater price generally varies from $250 to $2000. The natural gas tankless water heater is more expensive than the electric type. If you are lacking money or don’t have gas pipeline, then you can choose an electric or propane model. 

Apart from the buying price, other costs are also involved like venting costs, using costs and few others. The indoor installation of natural gas or propane type heaters need venting facilities and you have to pay more costs upfront. The installation of electric type is cheaper. 

Best Tankless Water Heaters of All Time

  1. Best Selling Type – Rheem RTEX-13
  2. Best Large Flow Type – Rinnai RUC98iN
  3. Best Heater of Mid-Size or Large Family – EcoSmart ECO 27
  4. Best Whole House Type – Takagi T-KJr2-IN-LP
  5. Most Energy Efficient – Noritz NRC661-DV-NG

How to Determine the Proper Size of Tankless Water Heater?

What should be the ideal size of water heating system for your home? It is the most crucial step before you can actually buy a heating appliance for your home. If you are thinking that buying the large water heater without a tank will solve all purposes, then you are wrong. If you get an oversize one, then you will need more heating elements, and this will cost you much. It will be total waste of resources and money. 

On other hand, if you buy too small, you might have to install more small heaters in the house to meet your hot water needs. This is the last thing to occur. So, you should always be wise while making such choices to avoid any stupidity at the end.

In most of the cases, the more water you need, the larger and more powerful unit you will require to meet your hot water needs. The temperature drops in different regions might also affect your choice.

If you are living in warm areas, you can get a small capacity water heater as it needs less energy to warm the water. A heater with flow rate of 3-5gpm supporting two showers simultaneously will be a good fit for you. 

But for the cold areas, you require a heater with more energy and more pressure to activate the machine. A large electric or a powerful gas heater can be the ideal choice for you if they can support multiple showers at same point of time. 

Following is the chart representing average water temperature in different regions of America:

Region Average Groundwater Temperature Temperature Rise
Northern States 40° F 80° F
Midwestern & Southern States 50° F 70° F
Southern California, Southwest and Gulf States 60° F 60° F
Hawaii and Puerto Rico 75° F 45° F

Now, what you can do is check out the official website of the manufacturer to get a closer estimate of temperature in your country. There are online calculators as well. Your energy bills can be also helpful in deciding the best water heater without a tank for your home. After having a clear vision of temperature rise in your area, you can make your buying decision.

What are the Best Tankless Water Heater Brands?

There are numerous tankless water heater brands in the market, but the top selling and widely appreciated ones are as follows:

Buy Takagi Tankless Water HeatersTakagi

It is an affordable brand for buying tankless water heating machines and is majorly focused in manufacturing electric products. The flow rate is not so large, and the machines are ideally suited for studio houses with single bathroom or faucet. Most of them are portable ones and can be used by the travelers or in camping. You can have more details on Takagi tankless water heaters and read their reviews. 

Buy Rheem Tankless Water HeatersRheem

It is one of the best water heater brands of all time and is appreciated by most of the buyers. The heaters are bit expensive but are pretty powerful. They can even support the entire house with multiple showers simultaneously. The constant hot water supply frees you from the trouble of running short of water while bathing. Check the best reviews of Rheem tankless water heaters and learn about its products. 

Buy Rinnai Tankless Water HeatersRinnai

It is a famous brand expert for manufacturing the propane or natural gas type of heaters. Its products are generally powerful and have large flow rate. They can comfortable meet the demands of two-three bathrooms simultaneously. One of its top-selling products is model number RUC98iN Ultra series. To get more information, read Rinnai tankless water heater reviews

Buy EcoSmart Tankless Water HeatersEcoSmart

This brand is dedicated to producing the highly efficient products technically that can save good amount of electricity. Most of its models are electric ones. The flow rate is quite low, but they are designed with compactness. You can easily install them anywhere you wish. They are as good as solar heaters. If you want to explore some of the top models of EcoSmart then go through EcoSmart tankless water heater reviews


The instant water heaters by Noritz are efficient for small-sized or mid-sized houses. But, some of them can also be suitable for whole house of large families supporting 3-4 bathrooms simultaneously. The warranty of heating part is also 12 years and the service staff is proved to be satisfying. Check out more products of Noritz tankless water heaters here. 

These are the top 6 water heating system brand that people usually prefer. There are other water heaters brands as well. You can check them out of you are not willing to buy the product from the above list.

How to Choose the Best One?

You need to follow certain steps to choose the most reliable and trustful water heater without a tank for your house. 

Firstly, start from famous and top-selling brands. Read through the customer reviews for different models from those brands. Now classify the applications for each model and identify the shortcomings as well after reading the reviews.

Then according to the choices made, classify them based on energy efficiency, flow rate and quality of service. Then only pick the best one according to your needs.

Reliability is also an important criterion to make a choice. Check the warranty time, warranty methods, after sales services and feedback from customers. You can find more information on choosing the best tankless water heaters on the web.

What is the Price Range for Tankless Water Heaters?

The price of tankless water might vary according to the type, flow rate, and other factors. Generally, the heating system having a larger flow rate would be expensive from those having lower flow rates. When we compare power and efficiency, the natural gas type is better than electric one and therefore it is expensive too. It is capable of supporting multiple showers simultaneously and well-suited for whole house or commercial purpose. 

A point of use or portable travel water heaters are available at much cheaper price. They are specifically designed with lower flow rate and can support studio home with single bathroom. Apart from the purchasing price, you should also consider other factors too.

The tankless water heaters can be used for 15-20 years easily and the using cost would be expensive then the machine price itself. Therefore, ensure that you always choose the one with better quality and capabilities. It will save a large amount of money in long run that ordinary tank water heaters can’t.

Choosing an energy efficient water heater will save you more money. The electric types are cheaper but may be costly in long run. Going with gas type models might be costlier in starting but can save you a huge money if used for long run. You can check the price on Amazon.

The Cost of Installation

The installation cost is one of the major concerns that must not be neglected before buying the tankless water heater. For each type of these heating systems, the installation process is different and so is the cost. Installing the electric type heaters is much more cost-friendly as compared to the natural gas or propane gas ones. 

The natural gas or propane gas heaters require venting facilities and special pipes that can cost your pocket much. But they can be cheaper in long run saving electricity.

The safest and reliable method of installing these heaters is calling the professionals or expert at your home and paying them for their services.

If you are installing these heaters in your home, you will need permit for the same. Most of the countries or cities will require you to get the permission for this project and this might cost you $45-$200 depending upon the difficulty of process. Most of the installation firms choose to charge the amount depending on the hours a job will take. On a rough estimate, it will cost $50 for an hour and the job will require 3-4hours. 

If you are intending to replace the old tank water heater with the new tankless model them make sure that the new machine is compatible with old system. If not, then the installation will cost you at least $500. For the new home installation, you ought to buy the gas or power lines. The whole installation process might take around 3hours. 

How about Installing the Tankless Water Heater at my Home?

Installing the water heater is a really sensitive task. For the electric types, you need to have a 220v to 240v power outlet and for gas type, you will require a pipeline to be added. The major part is that, for most of the manufacturers, the warranty works when licensed experts install the devices at your home or commercial space. 

You might lose the warranty if the installation is done by yourself. We also recommend taking the help of a professional expert or call expert from the company before installing such device at your home, especially for the whole house model.

If you do not know more about plumbing, you can even install the portable type by yourself. The installation is not at all complex and require only a few tools. But it might take you hours to finish this job. 


  • For Indoor Tankless Water Heaters
        • For gas or propane type, install the unit in airy space. They must not be installed in your bathroom.
        • You should leave some distance between the unit and other things in installation.
        • You must keep the heater dry all the time.
        • Install it in a place from where it is convenient to operate.
        • Do not put anything on the machine.
        • Do not allow your child to operate by himself or herself.
        • Always go through the instructions carefully.
        • Turn it off if you are not using it for a long time.
        • Stop immediately if it is not working fine.
        • Check the machine on a regular basis.
  • For Outdoor Tankless Water Heaters
      • You should get protection cover for the machine to protect it from poor weather conditions.
      • Do not put any inflammable thing on it.
Frequently Asked Questions (FAQs)
  • Do I need to wait for a long time for hot water to flow?

You don’t have to wait for a long time to get hot water running as one of the features of this instant water heating machine is to provide hot water instantly. It heats the water and the water reaches the peak temperature as soon as you open the tap. The distance between the heater and tap is the only metric defining the waiting time of hot water. The longer the distance, the longer it will take for hot water to reach the tap. 

  • Does a tankless water heater operate differently when I use shower?

Most of the manufacturers recommend you use hot water by turning the tap on and then cooling it by adding cold water to it. This will deliver the best performance of heater. 

  • Can the heater still work if power is out?

For many electric units, the water is still allowed to flow at times when power is out, but the heating element will not work without power. If you are having battery backup or any other source of electricity, the only you can expect hot water.

  • Is the temperature or flow rate gets impacted by altitude?

The climatic conditions and altitude will definitely affect the flow rate and temperature of water especially for gas type models. When the water arrives at 4000 feet, the gas type heater begins losing its efficiency at a rate of 4% per 1000 feet and the flow rate drops by 2-3gpm for large flow type. The electric tankless water heater is not affected by the altitude or climate change.

The Wrap Up

The tankless types of water heaters are becoming more and more popular around the globe. They give instant water supply and performance. Most importantly, they save space and are efficient in long run. The urgent need of this fast-paced world is to save time and these tankless water heaters do this for them.

We expect that you have got enough knowledge after reading the reviews and knowing about different types of tankless water heating systems available in the market, popular brands, buying guides, price, installation with some other details. You can ask the manufacturers directly if you need any further assistance or help. 

If you require some other details, check out the Amazon Store for the same purpose and choose from the wide range of tankless water heaters available.