What Are The Best Tankless Water Heaters In 2019? (And How To Choose One!)

Tankless water heaters are a great way to save floor space while heating your water efficiently and economically! These heaters can hang on a wall, and they heat water as it passes through the tankless water heater to give you a toasty shower or bath that you’ll enjoy.

The best tankless water heaters will provide great flow and temperature rise so that every fixture in your house gets hot, pressurized water while in use. Let’s examine the top choices!

**Below, you'll find more detailed reriews, but you can click links above to see current prices and read customer's reviews on Amazon


The Best Tankless Water Heater Buying Guide

When you’re shopping for a tankless water heater, there are a few things you should consider to make sure that you’re choosing a water heater that will work for you and your family long term. Let’s break down the most important things to consider when making your selection.

Total Flow Rate

The most important thing to consider when looking at tankless water heaters is the flow rate that it can give you.

To understand why this matters, you need to have a basic understanding of the plumbing in your house. Each fixture, such as your shower, has a specific flow rate that it runs at. You will want to add up the total flow rate that you expect to use at one time.

Use this chart to figure out the flow rate:



4.0 GPM


2.5 – 3.0 GPM

Washing Machine

2.0 GPM


1.5 GPM

Kitchen Sink

1.5 GPM

If you wanted to run 2 showers at one time, you would want a tankless water heater that can handle between 5.0 and 6.0 GPM. The demand on the water heat would be this much, and if it cannot handle it, you will have bad water pressure.

To decrease flow rate in your home, it is also possible to install fixtures that have a lower flow rate. This helps you get a smaller water heater, and it also saves water!

Temperature Matters

Another important part of choosing a tankless water heater is considering what temperature it can heat to and how quickly. Have you ever taken a shower and been disappointed that the hot water didn’t last more than 10 minutes? That was because of the water heater!

You can solve this problem by making sure that your tankless water heater has the right temperature abilities that you need.

To figure out what temperature rise you need, you should know what temperature the water that comes into your house is. Follow these steps to figure out what temperature rise you need:

  • Find out what temperature incoming water is. In most cases, it is around 50°. If you don’t know, use this as a baseline or call your water company for advice.
  • Determine what temperature you want your water to be heated to. Chances are, you will want your water heated to be around 105–115°.
  • Then, do the math! You will need a tankless water heater that produces a temperature rise of at least 55° in this example.

If this seems complicated, call a local home improvement store and ask for their help in determining what size heater you need.

Additionally, many tankless water heaters are rated to accept a wide range of incoming temperatures, which makes the buying process easier.

Gas Or Electric

Like many appliances, tankless water heaters can run on either gas or electric energy. What you prefer to use is up to you, but there are some key differences.

Gas tankless water heaters tend to be able to produce a larger temperature rise per GPM than electric models. If you need a very high temperature rise, you’ll likely want to look to gas.

You can usually get up to a 70°F water temperature rise at 5 gallons per minute with a gas-run water heater. For electric, that temperature would only be possible at 2 gallons per minute. Depending on your needs, one might be better than the other!

It is important to mention that there are more efficient electric water heaters than this average. If you choose a very efficient electric water heater, you can get a higher flow rate with a good temperature rise.

Are You Sure You Want Tankless?

The last thing to think about when choosing your tankless water heater is to make sure that you want a tankless version! Many people like the idea and energy savings that a tankless water heater can provide without realizing that it might not be the right choice for their home.

Here’s a basic breakdown of the main uses for each type of water heater. Make sure you match up with tankless!

  • Conventional Tank : This tank stores water that is constantly heated. Efficiency in these models varies a lot, but they can hold between 20 and 80 gallons. These are quite large and usually go in a basement, garage, or closet.
  • Tankless : This type of tank heats water as it passes through the heater. It can run out of water during heavy usage but saves up to 30% on energy consumption. They take up very little space and can be hung on a wall.
  • Hybrid : This type of tank heats cold water with an electric element that uses a heat pump to take heat from ambient air. They can create hot water 33% faster than a standard, electric water heater.

Top 5 Best Tankless Water Heaters

If you’re sure that you want a tankless water heater, move on to the next section to discover the top 5 best tankless water heaters on the market!

1. EcoSmart ECO 27 Electric Tankless Water Heater

Via Amazon.com

This durable, compact tankless water heater has a great design that is appealing both aesthetically and economically. It can save up to 50% on water heating costs thanks to how efficient it is, and a digital temperature gauge makes it incredibly simple to adjust the temperature of the water in one-degree increments.

There isn’t a tankless water heater that is as efficient or easy-to-use as this one, making it one of the top choices of water heaters to buy in 2017.



  • Ideal for northern areas, where incoming water is as low as 37°F
  • Can heat up to 3 GPM at very low incoming temperatures
  • Can heat up to 6 GPM at warmer temperatures
  • Digital thermometer makes temperature easy to set
  • Can replace parts very easily
  • Stable water temperature
  • Works best with low-flow fixtures; pressure lower without them
  • Sheet metal enclosure bends too easily
  • Added installation costs for those not technically-minded
  • Cheap, plastic control knob

2. Eccotemp L5 Portable Tankless Water Heater and Outdoor Shower

Via Amazon.com

This next tankless water heater is a great choice for those who want to get a portable water heater to use at a vacation home, the beach, while camping, or just out in the yard. While it can be great to hose off after swimming or getting dirty outside, nobody wants to do it with freezing cold water! This portable water heater prevents that, and it’s a great backup to use if your in-home heater has any problems.



  • Portable and lightweightSimple to use
  • Can be used without electricity (takes D batteries, needs 12V pump)
  • Great for cleaning car, animals, yourself, and more!
  • Give enough temperature rise and flow for a very basic shower
  • Simple setup
  • Low propane use
  • Runs off of propane
  • Small temperature rise (30 to 35 degrees)
  • Low flow rate (1.5 gallons per minute)
  • Will get leaky if you let it freeze
  • Need to use filtered water to avoid mineral buildup
  • Flimsy shower head

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

Via Amazon.com

This indoor, tankless water heater from Takagi has a max flow rate of 6.6 GPM which will be more than enough for most users. It is one of the most consistent water heaters because it has temperature gauges on both incoming and outgoing water to help regulate the temperature. This unit can be professional installed, or you can install it yourself by following the detailed instructions carefully.



  • Hot water lasts for a long time
  • Can be installed by homeowners with included instructions
  • Very small and light
  • Temperature controller displays incoming and outgoing water temperature as well as flow rate, making it easy to monitor
  • Can change the outgoing temperature regularly and easily
  • Not good for old houses
  • Can not run 2 showers at once at max temperature
  • Should be recalibrated at altitudes above sea level
  • Expensive to have it installed

4. Rinnai RUC98iN Ultra Series Natural Gas Tankless Water Heater

Via Amazon.com

This is a natural gas, tankless water heater made by Rinnai. It can be used residentially with a temperature range of 98° F to 140° F. In commercial locations, it can be set to have a range of 98° F to 185° F. This product is made of high-quality parts in Japan, and it is very durable. The unit is likely to last you for years to come.If you want a tankless water heater that will not fail in a short amount of time, then this is the right choice.



  • Very quiet
  • Lasts for years
  • Includes 12-year heat exchanger warranty, 5-year parts warranty, and 1-year labor warranty
  • Easy to flush it to maintain
  • Helpful customer service available
  • Very efficient
  • Accurate temperature control
  • Informative manual helps set-up and maintain it
  • Seemingly endless hot water
  • Should be run with low-flow fixtures for best flow rate results
  • Slight dip in water pressure for many users
  • Takes a bit longer to heat water than other units

5. Rheem RTG-84XLN 8.4 GPM Low NOx Outdoor Tankless Natural Gas Water Heater

Via Amazon.com

The final tankless water heater on the list today is this model from Rheem. This unit is meant to be installed outdoors rather than indoors due to the venting, but this is preferable for many people who are hoping to keep the water heater out of the house to save space. It can run a 8.4 gal/min. at 35-Degree rise, which is enough for many homes. It will run at larger temperature rise requirements, but the GPM will be much lower.



  • 8.4 GPM at 35-degree rise
  • 6.6 GPM at 45-degree rise
  • Can control temperature in 2-degree increments
  • Endless hot water
  • Reliable, consistent water temperature
  • Very compact design
  • Efficient
  • Only has 35-degree rise at may GPM, not good for homes where it freezes over often
  • Heats slowly
  • Water bill might go up (because you’ll be using so much hot water!)
  • Expensive to professionally install

Take Home The Best Tankless Water Heater

No matter what house you live in, a tankless water heater can be a great way to save on energy consumption and get consistent, hot water in all of your fixtures.

When it comes to the top of the line, however, it’s clear that the EcoSmart ECO 27 Electric Tankless Water Heater is the king! It runs at 27 KW at 240 Volts and gives consistent, reliable hot water to a wide variety of homes, regardless of your incoming water temperature. If you had to try one water heater, let it be this one!

Make sure to comment with your thoughts about tankless water heaters below, and share with any friends who have dismal water pressure and temperature in their home!

Sophia Gardner

I'm Sophia, food blogger, dog lover, homemade cooking and travel passion. I really hope you enjoy my blog, i'll do my best to share great recipes, healthy living tips and just general 'food' thoughts!

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