4 Best Whole House Tankless Gas Water Heater Reviews 2020

Whole house gas tankless water heater is considered a good purchase as it can save you money in the long run. Tankless water heaters, as the name signifies, are the water heating units without a tank, which supply hot water on demand instead of storing it in the tank. But make sure that they are powerful enough to pump out the gallons per minute you need. There are three types of whole house tankless water heaters:

Best Whole House Tankless Gas Water Heaters Reviews:

Do you want to save a nice chunk of change every month? Then installing a whole-house gas tankless water heater would be the right decision. We have provided a detailed review of the top 4 whole house gas tankless water heaters below after checking the features of each product.

  • Flow rate:

It is a whole house tankless water heater that has a flow rate between 0.5 to 6.5 gallons per minute. Though the flow rate of the unit is lower than the other units (which will be discussed later), it still supports two bathrooms and multiple faucets at the same time.

  • Endless hot water:

It is an efficient tankless water heater that provides hot water without interruption.

It is a tankless water heater that has a low NOx design and consumes less energy. It means you will be able to save money on energy bills every month.

  • Water temperature:

The water temperature of the unit reaches 140oF, which makes it perfect for whole-house use.


  • Remote control (optional)
  • Freeze protection system
  • Easy installation
  • Compact unit
  • Low NOx design
  • High efficiency


  • Coldwater sandwich problem
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2. Rinnai RL75iN Natural Gas Tankless Water Heater:

Rinnai RL75iN

  • Digital control panel:

It comes with an easy to use digital control panel which features an error code indicator so that you can troubleshoot if a problem occurs.

  • Compact design:

The unit has a compact design so that you can mount the unit on a wall or install it anywhere else.

  • Flow rate:

With a flow rate of 9.6 gallons per minute, it supports 3-4 bathrooms in warm areas. However, it supports only two bathrooms if you live in cold climates.

  • Efficiency:

The unit offers a great thermal efficiency of 86%. If natural gas is not available, you can convert the unit into the propane water heater.


  • Quiet working condition
  • Commercial use available
  • Works in altitudes up to 10,200 feet
  • Can be vented either horizontally or vertically
  • Reliable unit
  • Easy temperature control settings
  • Constantly hot water offer


  • Venting kits can be a little hard to install
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3. Takagi T-H3-DV-N Condensing Natural Gas Indoor Tankless Water Heater:

Takagi T-H3-DV-N

  • Compact and space-saving:

With a body measuring 11.2 x 17.8 x 24.9 inches, it is a compact tankless water heater, which means it will not take much space in your home no matter where you install it.

  • On-demand water heater:

The unit provides an endless supply of hot water on demand and consumes less energy, which means you will not have to pay huge amounts as energy bills every month.

  • Flow rate:

It is a tankless water heater that has a pretty large flow rate. The flow rate reached to 10 gallons per minute, which means it supports two bathrooms in cold areas and three bathrooms in warm areas.

  • Water temperature:

The water temperature reached as high as 1450oF, which makes it one of the best tankless water heaters that can be used for commercial purposes as well. Also, the water temperature does not drop even when you use the kitchen and bathroom sink at the same time.


  • Energy Star® qualified
  • Digital control panel
  • Lightweight
  • Compact design
  • Endless hot water
  • High volume output
  • 5-yearlimited heat exchanger
  • Integrated controls and power cord


  • The temperature may fall in cold areas
  • Expensive installation
  • May wait a bit longer to get hot water
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4. Rinnai RUC98iN Ultra Series Tankless Water Heater:

Rinnai RUC98iN Ultra Series 2020

  • Commercial use:

It is a tankless water heater that can also be used as a commercial water heater. But you need an extra commercial remote for this.

  • Water flow:

The first thing you should check before buying a tankless water heater is the flow rate. With the maximum flow rate of 9.8 gallons per minute, Rinnai RUC89iN can meet the hot water needs of the entire home.

  • Efficiency:

The unit has a thermal efficiency of 95%, which means you would be able to save money on energy bills.


  • Optional venting options offer
  • Endless supply of hot water
  • High flow rate
  • Commercial use
  • Residential use


  • You need to get the services of a professional plumber to install the unit.
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Things You Should Consider Before Purchasing The Best Whole House Tankless Gas Water Heater:

Instantaneous of tankless water heaters are energy efficient that help you save money on energy bills. But buying the best tankless water heater is not a simple decision. There are many factors you have to consider before buying a whole house gas tankless water heater:

  • Energy-efficient:

Tankless water heaters are energy efficient as they do not consume much energy to heat water. They reduce the heating cost and every month you save money on energy bills. Make sure the unit you purchase is energy efficient and does not waste gas that pollutes the air. The units that have a thermal efficiency of 90% are considered the best energy-efficient tankless water heaters.

  • Flow rate:

If you are living in a large home, then a tankless water heater with a large flow rate is needed. There is no point in installing a tankless water heater, which does not have the capacity to fulfill the whole house hot water requirements. Check the flow rate before buying a tankless water heater. It is highly important to check that the unit you are buying supports more than one bathroom or faucet at the same time or not.

  • Venting:

If you are installing a gas tankless water heater indoor, then you need to install venting facilities for safety. You should know how to install the venting facilities and what inch of the pipe is required. In case you are installing an outdoor gas tankless water heater, then no venting is required.

  • Size of the unit:

Whole-house tankless water heaters provide hot water to meet the needs of the whole house. But not every tankless water heater is large in size. There are many tankless water heaters that are compact in size but have a large flow rate. So, make sure you know what size you need.

whole home tankless water heater 2020

 Advantages/Pluses of Best Whole House Tankless Gas Water Heater:

  • Endless supply of hot water:

People are now switching from tank to tankless water heaters as it is convenient to use them. All you have to do is to choose one model as per your needs and install it anywhere you want. Then you will be having an unlimited supply of hot water without any problem. No matter you are doing laundry, taking a bath, or washing the dishes, you have to wait only for a few seconds, and you will get hot water.

  • Money-saving:

One of the biggest advantages of tankless water heaters is that they are energy efficient and help you reduce energy bills. But whole-house gas tankless water heaters also save your money on installation and maintenance. You may be aware of the fact that installing a point of use tankless water heater means you have to pay a double installation fee.

  • Cost-effective:

Whole house gas tankless water heaters are cost-effective as you do not need to install a point of use or under sink tankless water in the kitchen. It will be enough to meet the hot water needs of the whole home.

  • Space-saving:

Those who live in a small home want a solution to their hot water problems that does not take much space in the house. Tankless water heaters do not occupy much space, and you can install them anywhere you want to. You can mount them on the wall or install them under the sink. As far as whole-house gas tankless water heaters are concerned, there are some models that are small in size.

  • No bulky tanks:

You get rid of those bulky tank water heaters that occupy much space in the home. If you live in a small home, then installing the conventional tankless water heater is a headache. But a whole house gas tankless water heater is compact and lightweight.

The Best Whole House Tankless Gas Water Heaters:

Best one for commercial use

Takagi T-H3-DV-N Tankless Water Heater

Takagi T-H3-DV-N High-Efficiency

Most Powerful one

Rinnai RUC98iN Tankless Water Heater

Best Rinnai RUC98iN Natural Gas Ultra Tankless Water Heater Reviews 2020

The most energy efficient one

Noritz NRC661-DV-NG Tankless Water Heater

Noritz NRC661-DV-NG

If you are looking for a tankless water heater for a large home, then whole house gas tankless water heater is the best choice. You can also check other types of tankless water heaters on Amazon. What are you waiting for? This is the time to replace your tankless water heater with an energy-efficient tankless water heater.