Best Tankless Water Heater for Whole House Reviews 2022

Best Tankless Water Heater Guide

While conventional water heaters remain the best choice for some, tankless models save room and can help lower your heating bill.


If you’re considering for best tankless water heater, your first decision will be to pick a gas or electric model. While high-end gas models may be more effective than electric ones, they are also considerably more costly and hard to install. Also, tankless water heaters save gallons of water per minute as compared to storage water heaters. Because one has to wait in the shower until hot water starts flowing in.


There are also some other safety concerns to consider. Some homeowners would not prefer using gas. Gas tankless hot water heaters are typically not efficient compared to the electric tankless water heater, so there are many reasons to select an electric tankless water heater.


1.Stiebel Eltron 239223 Tempra 29 Plus | Best Tankless Water Heater​

Stiebel Eltron has a great experience with best electric tankless water heaters. The high-quality Tempra 29 plus is rated for up to 4.5 GPM. In addition, it can raise the water temperature for one or two showers well by 90 degrees Fahrenheit level, making it an impressive yet economical choice for homes. This model is equipped with exclusive Electronic Temperature Control that ensures steady output temperature even with varying flow rates.

It is easy to install. Operation is simple, with an Exclusive design that prevents dry firing and an Electronic switch activated for virtually silent operation. In addition, the tankless design prevents Legionella bacteria growth. This model has a 28.8kW unit requiring a 240V supply and 3 x 40 DP breakers.


  • Sleek design
  • saves space
  • no venting required


  • Tempra 29 will only handle approx. 2.6 GPM flow rate

Rheem also has a great experience with gas tankless water heaters. The high-efficiency indoor natural gas tankless water heater is rated for up to 9.5 GPM.

In addition, it can raise the water temperature for up to four bathrooms to 120 Degrees Fahrenheit, making it an impressive yet economical choice for homes. Furthermore, this model has an exclusive Digital Remote Thermostat that ensures steady output temperature even with varying flow rates.

Based on Department of Energy (DOE) test procedures, Rheem gas tankless water heaters have a Water Savings Setting. When this setting is enabled, water waste is reduced by up to 1,100 gallons per year.

Rheem indoor tankless gas water heaters are small & compact – saving you valuable space in your home. They can easily be wall-mounted in tight spaces – like in a utility closet, attic, or storage room – and only need ½” clearance on both sides. Hence, it is another best tankless water heater.


  • Low operating cost
  • Water & Gas Leak Detection will shut down unit
  • automatically adjust the amount of energy required to heat the water


  • Relatively Expensive.

Another best tankless water heater is Tempra 12 Plus. With its Electronic switch that activates the hot water heater, Stiebel Eltron Electric Tankless Water Heater Tempra 12 plus has a digital temperature display, preset temperature, and memory buttons, while the internal solid copper heating system does all the energy work. 

This unit is 12kW, 240V requires a min recommended electric service of 100A, and delivers an output temperature of water from 68° to 140°F.

It reduces the flow of hot water when demand surpasses the capacity to ensure that hot showers will never be interrupted. Tempra 12 Plus will typically consume 15-20% less energy compared to conventional electric tankless water heaters


Its small, sleek design saves space and no venting is required.


  • Continuous Flow
  • Noise free
  • Excellent warranty
  • Space saver


  • Not recommended for large households

With its advanced technology, comfort, and value, this Rinnai’s model is another best tankless water heater. Its models offer a compact tankless water heater that has a longer lifespan. Unlike tank heaters that accumulate rusty sediments, this model heats water on demand only, saving energy costs. The flow rate of this is unit up to 5.3 GPM. 

It also comes with safety features that include Flame Failure -Flame Rod, Boiling Protection, Combustion Fan RPM Check, Over Current-Glass Fuse, Remaining Flame (OHS), Automatic Frost Protection, and Thermal Fuse


  • Endless Hot Water
  • Space-saving design
  • Value for money


  • No Temperature Controller
  • Indoor installation requires an exhaust

Another best tankless water heater is  Rheem RTEX-24. If you want continuous hot water quickly, then this 99.8% Energy efficient tankless electric water heater is perfect for a single point of use or multiple application.

It is Compact and stylish, with digital temperature control in increments of 1°F ranging from 80°F to 140°F. Its flow rate for the whole home is up to 6GPM.

It is a 24.0Kw unit, and a breaker of (3×40)AMP is recommended by the company.


  • Simple Installation.
  • Digital temperature display.
  • External controls to adjust temperature in increments of 1°F.


  • No reserve water when power goes out.
  • Installation requires knowledge of installing breakers.

This eco 8 tankless water heater only turns on when you need hot water. As a result, it cuts down on heat loss, saving you up to 50% in water heating costs, according to the DOE. Also, instead of storing hot water like a traditional tank water heater, it heats water as it passes through the unit.

Also, this ecosmart electric tankless water heater comes with Advanced self-modulating technology, this unit has digital temperature control that raises water temperatures from 80 – 140° F. Likewise, this eco 8 water heater is an 8-kilowatt tankless electric water heater ideal for providing hot water for a bathroom, small sink, and office breakroom.

For installation, this electric ecosmart tankless water heater requires a breaker of (1 x 40)AMP and Water Connections of 1/2″ CF.


  • Save up to 50% on your water heating costs.
  • Compact design.
  • Advanced self-modulating technology.


  • EcoSmart would not honor the warranty if the unit is not registered within 30 days.
  • Not recommended for more than 1 bathroom.

Designed for continuous hot water, Rheem RTG-84XLN-1 is an outdoor natural gas tankless water heater. With a minimum flow rate of .26GPM and a minimum activation flow rate of .40GPM, it ensures hot water is received even in low-demand situations. Also, it gives a maximum flow rate of 8.4GPM

It comes with a Digital Remote Thermostat. Furthermore, no venting is required as this unit is for use outdoors. And this unit is best if used with up to 3 bathrooms.

Item Dimensions are LxWxH‎8.88 x 13.88 x 23.63 inches, and Water/Gas Connections required for installation are 3/4″.


  • Value for money
  • Easy to install
  • Tech Support


  • Compared to electric ones, gas water heaters take little time to heat.

This 8kW model provides up to 1.95 gallons of hot water per minute (GPM), enough for 1 shower.

The Digital temperature control on the front of this model allows easy set point adjustment. It does not require venting, so it can be installed anywhere inside your home.

It is pertinent to mention the installation process. This unit’s Dimensions are LxWxH 12.6 x 8.25 x 3.63 inches. The Breakers required for this unit are (1 x 40)AMP and side 1/2″ NPT water connections. Therefore, this best tankless water heater should be considered for a small household.


  • On demand continuous hot water
  • Self-modulating power control
  • Dial Control with adjustable digital temperature display


  • Only works with 1 shower.

Q: What is a tankless water heater?

A tankless water heater is a device that heats water on demand without storing it in a tank. It uses gas or electricity to heat the water as it flows through a heat exchanger. Tankless water heaters can provide hot water faster and more efficiently than traditional tank models.


Q: What are the benefits of a tankless water heater? 

Some of the benefits of a tankless water heater are:


Q: How do I choose the best tankless water heater for my home?

To choose the best tankless water heater for your home, you need to consider several factors, such as:


Q: What are some of the best brands and models of tankless water heaters?

Some of the best brands and models of tankless water heaters are:


Q: How do I maintain my tankless water heater?

To maintain your tankless water heater, you should follow these steps:

  • Flush your unit regularly with vinegar or a special descaling solution to remove mineral deposits that can affect its performance and efficiency.
  • Replace your filter screen or cartridge periodically to prevent clogging or damage from debris or sediment.
  • Check your venting system for any leaks, blockages, or corrosion that can cause safety hazards or reduce efficiency.
  • Consult your owner’s manual for specific instructions on how to troubleshoot any problems or issues with your unit.
Why Is My Hot Water Heater Whistling

The topic of hot water heaters and their associated noises can be a common source of confusion and frustration. A whistling sound may cause concern, as it is unfamiliar to the average homeowner. This article seeks to address why hot water heaters whistle and what steps may be taken in order to ...

How To Install Under Sink Water Heater

Under sink water heaters provide a convenient way to have hot water available at the tap. They are easy to install and require minimal maintenance once they are in place.  Installing an under sink water heater can be done quickly with some basic tools, making it easier for anyone to get ...

How To Remove Sulfur Smell From Hot Water Heater

The smell of sulfur can be a nuisance in your home, particularly when it is emanating from your hot water heater. This odor often occurs due to the presence of bacteria and other contaminants that accumulate within the water tank over time. Fortunately, there are steps you can take to alleviate ...

How To Remove Water Heater Element Without Socket

Removing a water heater element without using a socket can seem like an insurmountable task for those unfamiliar with plumbing. Yet, with the right knowledge and equipment, it is possible to successfully complete this undertaking without professional help. This article will guide readers through ...

Show next
Enable registration in settings - general