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Best Tankless Water Heaters 2020 – Reviews & Buying Guide

An insider review and buying guide of the best tankless hot water heater for 2020
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The best tankless water heaters of today are top quality on demand hot water heaters designed to only heat water when you need it, thus saving you energy and money.

They are portable, and they heat water pretty fast. Welcome to the modern way of heating water, and this tankless water heater reviews and buying guide will guide you on how to choose the best tankless water heaters for your home.

creative tankless water heater image for the best tankless water heater reviews and buying guide

For those who do not know.

Tankless water heaters are on demand water heaters also referred to as instant hot water heater, operated either by electricity or gas to give you hot water just when you need it.

They heat water directly without the use of a storage tank.

Chances are that you are looking for the best electric tankless water heater for your home OR in need of a good tankless gas water heater for outdoor and in cases where there is electricity shortage, but do not know which hot water heater to go for.

Review of the best tankless water heaters 2020: top electric and gas heaters on the market

Smarthomeradar recently tested several electric and gas whole-home tankless water heaters from brands such as Bosch, Navien, Noritz, Rheem, Rinnai, Tempra, and Trutankless. After series of tankless water heater reviews, we have shortlisted the best tankless water heaters for homeowners seeking for on demand heated water below.

Here then is a reviewed list of the best tankless water heaters to buy in 2020:

1. Ecosmart Eco 27 Electric Tankless Water Heater

Our top pick of the best tankless smart electric water heater 2020

Before now, Eco has been know to be one of the best tankless water heater brands, and the Eco 25 is the proof to show for it.

Ecosmart Eco 27 electric tankless water heater
Ecosmart Eco 27 electric tankless water heater review

Heater Type: Electric tankless | Dimensions: 17H x 17W x 3.625D inches | Weight: 13.75 lbs

you can buy from Amazon US, UK, CA, AU and Best Buy (prices are lower when discount is applied) – Use the button above.

The EcoSmart ECO 27 is an energy efficient tankless water heater that works well in small, medium and average homes that don’t have huge demands for hot water constantly running.

The Design.

Featuring a digital display that lets you set the exact water temperature between 80 and 140 degrees Fahrenheit, the Eco 25 and 27 is a compact electric water heater that can fit perfectly well even in homes with small or little storage space.

For the main build, Ecosmart used Copper and Stainless steel components, which have the ability to withstand high temperatures, while transmitting the heat from one end to the other, thus makes this unit a durable on demand hot water heater.

Performance and Features.

Using the ECO 27 self-modulating technology, it makes sure the heater draws energy only when it needs it. This technology leads to an increased energy savings of upto 50% and a high heater efficiency. Yes, this heater heats water very well and fast.

Flow Rate.
The Eco-25 smart water heater is able to give you up to 3 gallons of hot water per minute in areas with temperatures as low as 37 degrees Fahrenheit, and up-to 6 gallons per minute, in areas where the temperature of the incoming water is high.

What this means is that, it can power up to four showers and a sink at the same time without running out of hot water.

Ecosmart Eco 27 tankless water heater PROS. and CONS.
  • Digital display and temperature control allows easy control and monitoring of the temperature required.
  • Copper and Stainless Steel components makes it very durable.
  • Patented self-modulating unit provides best in class industry leading energy efficiency (about 1-3% higher than other leading models), which saves you more over time.
  • For areas with mineral-rich water, extra care is required for the copper elements care.
  • When household demands exceeds the units capacity, you may get cold water instead. In which case, an installation of a valve to throttle the flow rate is recommended to get thing back up balanced.

The EcoSmart ECO 27 is a compact and highly efficient tankless water heater electric model with enough capacity to heat water on demand for two showers running simultaneously. No doubt, the ECO 27 is one of the best smart water heater on the market, an excellent choice for home owners who wants to save money and reduce their environmental footprint.


2. Stiebel Eltron Tempra 24 Plus Electric Tankless Water Heater

The best electric tankless water heater

Packing an incredible flow rate of up-to 4.68 gallons per minute (GPM), this on demand tankless water heater rivals many gas-powered heaters of the same size.

Stiebel Eltron Tempra 24 Plus electric tankless water heater
Stiebel Eltron Tempra 24 Plus electric tankless water heater review

Type: Electric heater | Dimensions: 4.6W x 16.6H x 14.5D inches | weight: 1 pounds | Minimum flow to activate unit: 0.50 GPM

you can buy from Amazon US, UK, CA, AU and Best Buy (prices are lower when discount is applied) – Use the button above.

For those who probably haven’t heard the name before, Stiebel Eltron is a German electronics manufacturer considered to be one of the world’s leading specialists when it comes to manufacturing water source heat pumps.

The Design.

The design of this tankless hot water heater is somewhat unique in the sense that, it makes by far, less noise than other units listed here. This is done with the high-grade electronic parts and a reliable cover, which do not vibrate and, there is no mechanical switches.

Features and performance.
Talk of the word efficiency in a water heater and I will show you the steibel electric water heater tankless.

What really separates this tankless water heater from a majority of other instant hot water heater is its built in “Tempra Advanced Flow Control”, which by the way unique to Stiebel Eltron tankless water heater technology.

What this does is, while some tankless water heater models may produce cold water if the flow rate exceeds the heating ability, the Tempra 24 Plus automatically reduces the flow rate to keep the water temperature steady, so you get no cold surprises.

Flow Rate.

With a flow rate of up to 4.68 gallons per minute, this electric tankless hot water heater rivals many gas-powered on demand hot water heaters. and all thanks to its advanced flow control technology, no matter how much you experiment with the flow rate, the water temperature will always stay constant.

Stiebel Eltron Tempra 24 Plus electric tankless water heater PROS. and CONS.
  • Energy efficient: self-modulating technology modifies the heater to keep its energy intake constant.
  • An advanced control over the flow and temperature of the water gives you enough flexibility to either reduce the flow to save more energy or tune the temperature to your exact liking.
  • Sleek design, can fit properly in homes with little to no space and quiet during operation.
  • I am sorry, but the only con I could pick out is that, Stiebel warns that you hire its licensed personnel to install the product if you wish to keep your 3-years warranty valid.

With Over 90 years of experience gone into this product by a renowned tankless water heater brand, the Steibel eltron plus is no doubt one of the best tankless water heater available. Its also equipped with a large display that shows you the temperatures in an easy-to-read digital format, and a highly responsive dial selector that allows you to set the temperatures to suit you.


3. Rinnai RUC98iN Ultra Series Natural Gas Tankless Water Heater

The best gas tankless water heater for large homes

An Energy Star Certified water heater with lots of venting system installed to keep the environment safe.

Rinnai RUC98iN natural gas tankless water heater
Rinnai RUC98iN natural gas tankless water heater review

Type: Natural gas and propane | Dimensions: 10 x 18.5 x 26 inches | Weight: 82 pounds | Flow Rate: 9.8 GPM | Voltage: 120 volts

you can buy from Amazon US, UK, CA, AU and Best Buy (prices are lower when discount is applied) – Use the button above.

Who is this hot water heater good for?
If you live in a large house or have a big family that needs hot water running on demand to multiple faucets and showers simultaneously without fail.

The Design.

Firstly, this is a natural gas powered tankless water heater, and unlike other electric models out there, the design is unique and solid, with two ventilation systems mounted at the top which makes sure no form of gas is released within the house or place of installation.

The Features and Performance.
For the performance of this propane heater, the Rinnai gas tankless water heater gives out one of the best flow rates we have ever seen in a tankless water heater.

One of the biggest problems usually associated with Natural gas water heaters is the problem of venting. To ensure proper ventilation, Rinnai has equipped the RUC98iN with two venting options: first which is the concentric-PVC and the other – twin-pipe. You can choose between any of them that you find easy to install.

Flow Rate.

The ability of the Rinnai RUC98iN to heat water is amazing. This heater can provide hot water at a flow rate of between 7.5 GPM upto 9.8GPM. Which is large enough to completely power two to three bathrooms and even serve for commercial purposes. Although the flow rate does stems from the natural gas intake which varies from 15,200 to 199,000BTU.


During the cause of our tankless water heaters review, we found this propane on-demand hot water heater with a 0.95 efficiency rating. Something very few propane heater can achieve. So, yes, its safe to use.

Rinnai RUC98iN Natural Gas Tankless Water Heater PROS. and CONS.
  • Although this water heater is bulky (which is only normal to keep more gas and clean air ventilation), it does also occupies less space, with its unique space saving design.
  • It comes with smart chips to prevent short-circuiting so as to keep you and your family safe.
  • Advanced temperature lock system ensures that, once you’ve set the temperature, it remains the same without and change whatsoever.
  • Its bulky.
  • When household demands exceeds the units capacity, you may get cold water instead. In which case, an installation of a valve to throttle the flow rate is recommended to get thing back up balanced.

With an energy efficient level that can be compared to none, and a great heated water floe, the Rinnai RUC98iN is the best gas tankless heater on the market right now. You will find it very useful if you live in a large house or have a big family who wants heated water on demand without fail.


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

A top rated natural gas indoor tankless water heater

The Takagi T-KJr2-IN-LP is a mid-priced propane tankless water heater with good flow rates, sleek design and energy efficiency.

Takagi-T-KJr2-IN natural gas indoor tankless water heater
Takagi-T-KJr2-IN natural gas indoor tankless water heater

Type: Propane hot water heater | Flow rate: 6.6 GPM max flow rate | Weight: 38 pounds| Dimensions: 6.7 x 13.8 x 20.3 inches | Energy star certification: Yes

you can buy from Amazon US, UK, CA, AU and Best Buy (prices are lower when discount is applied) – Use the button above.

Takagi are known to produce high GPM machines and this unit is no short of quality. Even in cold climates, the Takagi K4 is still able to supply up-to eight (8) gallons of heated water per minute, which should be enough for two showers and a sink to run at the same time.

The Design.

This unit features a sleek and compact design. To be precise, this is actually one of the smallest tankless water heater in the Takagi line-up. The weight is 38pounds and measures at 20.3″ * 13.8″ * 6.7″, which is significantly small enough to place just about anywhere that is practically possible.

Features and performance.
When it comes down to heating water, the Takagi Tkjr2 does a really good job, to constantly provide heated water on demand.

First is an anti-freeze technology, which helps to keep its outdoor units running smoothly through all seasons, and a Hi-Limit Switch that Consistent water temperature is maintained through thermistors and an air-fuel-ratio (AFR) sensor that monitors efficiency and reduces emissions. All these put together not only helps this unit run smoothly, but also prevents unexpected bursts of cold water.

Flow Rate.

Takagi are known to produce high GPM machines, take for instance, their T-M50 model produces upto 14.5 GPM. The maximum flow rate of the Tagaki T-KJr2-IN-LP we saw was up to 6.60 GPM, which should be enough for small to medium sized houses with 1, 2 or 3 bathrooms.

Takagi-T-KJr2-IN-NG Indoor Tankless Water Heater PROS. and CONS.
  • Inbuilt evolutionary sensor and thermistors monitors efficiency while minimizing emissions.
  • Higher energy factors upto 0.83 as compared to tank gas heaters which generates 0.7. This thus helps you save more money while making sure you get constant on demand hot water in your taps and shower.
  • A general con of gas heater though, the cost of installation is a bit higher compared to the electric models because of the ventilation system that first has to be put in place.

If what you seek is a mid sized propane tankless water heater that can power upto two bathrooms and faucets, then the Takagi T-KJr2-IN-LP is one of the best propane tankless hot water heater you can buy in 2019.

“Went from a tank water heater to this and I love it. Was hesitant about switching to tankless, but it has been amazing, and our monthly electric was drastically reduced, and the increase in natural gas was minimal. I also love the fact that I can take a really long, hot shower and never worry about running out of hot water. Definitely recommend for anyone.”

Real life consumer and user.

5. Bosch Tronic 3000 T 7-Gallon Electric Mini-Tank Water Heater

Budget Friendly: The best cheap and portable tankless water heater with a mini tank

Our tankless water heater reviews wont be complete without this model. In fact, all you have to do to get it to work is simply tap into your cold water line and mount it directly – pretty simple and straightforward.

Bosch Tronic 3000 T Electric Mini-Tank Water Heater
Bosch Tronic 3000 T Electric Mini-Tank Water Heater review

Type: portable mini-tank electric | Dimensions: 10 x 10 x 16 inches | weight: 36 pounds | Size: 7 gallon

you can buy from Amazon US, UK, CA, AU and Best Buy (prices are lower when discount is applied) – Use the button above.

The Bosch tronic 3000 is a budget tankless water heater to go for, if you don’t have the money to splurge on the more expensive models, but still crave for something of great quality.

The Design.

The Bosch Tronic 3000 T is the smallest on demand hot water heater on this list. Its compact design makes it really unique, outside the fact that it can blend seamlessly with your interior decor, it so compact that it can fit under a sink, in a cabinet, or even on the wall with the included wall bracket.

Features and Performance.

Firstly, the Bosch 300T can be mounted virtually anywhere, indoors and outdoors. One striking thing about this unit is that, unlike other models that require venting, this portable tankless heater is a point of use on demand water heater, just plug it in and its working.

The Bosch Tronic 300 T may be small but its heating ability is commendable. It heats water at a temperature range of 65 to 145 degrees Fahrenheit which is enough for most needs in a typical household.

Bosch Tronic 3000 T 7-Gallon Electric Mini-Tank Water Heater PROS. and CONS.
  • Compact design makes it a great option for heating water in mobile homes, boats, and outside kitchens.
  • Point of use flexibility makes it a great option for your garage, basement, patio, kitchen or other rooms in the house.
  • Easy to set up.
  • Its small and compact, which limits its usage to smaller hot water needs. (I don think this is a con though, thats what it was manufactured for).

Here’s what real life consumers and users are saying.

“It’s so nice having instant hot water! This unit is very easy to install with minimal tools and know-how. It takes less than 20 minutes to install once you get the stuff from the hardware store. You will need to have an electrical outlet under the sink though, so check that before you buy this unit. I used a little cheap screwdriver, small pliers, and a cheap adjustable end wrench. You can do this! You will love the instant hot water.”

Real life consumers and users.

Although switching from a tank water heater to a tankless on demand unit can sometimes be expensive, obviously because it requires you to use the services of a plumber to retrofit your plumbing and possibly your electrical system. But if you’re building a new home, adding to an existing hot water heater, or just tired of the high energy bills generated by your tan heater, installing a tankless water heater may make economic sense.

Tankless Water Heaters Buying Guide and Review

Tankless Water Heater Installation: Who should do it?

Although it can be tempting to DIY and install your new tankless water yourself sometimes, most homeowners do not have the required skills and experience, it is recommended that a professional installs your water heaters correctly and safely while taking less time overall.

While a professional has all the required skills and knowledge to install your tankless water heater, they also offer professional advice on water heater suggestions for your home. To show how crucial this is, some tankless water heater brands only sell through certified installers.

How to Find a Professional Tankless water heater installer

To find the best plumber in your area, take some time to look at their online customer reviews on Yelp, Angie’s List, HomeAdvisor or other consumer reviews websites. If they don’t clearly outline their pricing and estimated completion time and provide a written quote, don’t use them, even if they are the lowest bid.

Factors to consider before buying a tankless water heater

Before you go all over searching for a tanless on-demand hot water heater to buy, it is important to put the following factors into considerations, to avoid compatibility and other issues faced by many home owners.

1. Electric Vs. Gas Water Heaters

Tankless water heaters usually use one of three power sources namely: electricity, natural gas or propane. In most cases, the type of tankless hot water heater you buy is decided by the power source you have in your home. It’s good you know what your options are, and if you have more than one power source, then you decide on which to use.

Electric tankless water heaters usually have lower operating costs but can be more expensive to buy. On the other hand, natural gas and propane models cost less to buy and have slightly higher operating costs. Additionally, gas models do not require electricity and can work when your power goes out.

2. Energy Efficiency

Generally, tankless water heaters use less energy to operate than conventional water heaters, though some models are more efficient than others, to maximize the energy efficiency of an on demand hot water heater, go for one that is Energy Star qualified.

However, keep in mind that the most efficient water heaters, like the Rinnai RUC98iN, usually have the highest prices. The Rinnai is not only efficient, but it runs off- using both natural gas and propane, and has multiple venting options. Sure do worth the price if you ask me.

3. Heater Size and Flow Rate

The bigger the size, the bigger the flowrate and the more water is heated faster, to serve multiple bathrooms and faucets, producing hot water constantly.

The size of a tankless water heater generally impacts and influences the rate and quality of heated water produced. If what you need is hot water for your entire home, then you are better off with a mid sized or larger unit with a high GPM (gallons per minute) to keep up with the demands of people using multiple faucets.

Very compact and smaller models with a flow rate of around 0.5GPM, may only work for a single bathroom or faucet. The good thing about them though is that, they can be used to add hot water to a garage sink outside your home.

Keep in mind that,
Tankless water heaters are only able to provide a fixed amount of heating based on the temperature of the water flowing through them. Hence, if you live in an area with colder climate, you need a larger model with a higher flow rate to produce the same amount of hot water a smaller one can in a temperate climate.

In Conclusion

All thanks to the federal regulations that now requires water heaters to be more energy-efficient. Tankless water heaters are better than they used to be. While new storage tank water heaters are required to operate more efficiently, tankless on-demand hot water heaters are even more efficient than that.

Thankfully, we’ve reviewed the best tankless water heaters availble for home and outdoors, ranging from electric to gas on demand hot water heater models. Feel free to use the comment box to voice your opinions , ask questions or contribute.

Resource Links.

Whole home tankless water heater buying guide –
Purchasing energy-efficient residential electric storage water heaters – Retrieved 2019

Other Related Buyer's Guide and Best Products Reviewed List
Here are some other related buyers guide and best products reviewed list of 2020 by Smart Home Radar.


  1. Really nice guide on choosing and buying a tankless water heater.. I also did do a review of the best water heaters recently and found this guide very helpful.

  2. Willie Duncan Reply

    It’s interesting that when I was a kid, 40 years ago, in Argentina, tankless was the standard and tanks were the “new” and “sophisticated” option. Now it’s the opposite.

  3. Thank you for the article. I have been thinking about replacing my water heater because it has started to break down and my dad lives there now. Figured instead of letting him fix it every time it breaks, installing a new one and I really didn’t want to go install a giant one.

    However, with how compact this is I will probably go and get started on this fairly quickly. Do you know anyone in Arizona you recommend for installing these?

  4. Luna Regina Reply

    The tips helped a lot in my choices for the family. Thanks a lot

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