4 Best 40-Gallon Natural Gas Water Heater Reviews For Large Family Shower Use

best 40 gallon natural gas water heater tankless

Natural gas water heaters can save you a lot of money on electricity bills. Most of us know how expensive it can be to raise a family with laundry and showers daily. The benefits increase if you decide to go with the more modern tankless variety. Tankless hot water heaters give you a constant supply of hot water on-demand. If you’re considering switching from electric hot water heating to the more economical natural gas, we have you covered with our reviews of the best 40-gallon natural gas water heater.

What Is the Best 40 Gallon Natural Gas Tankless Water Heater on the Market?

Top 4 Best 40 Gallon Natural Gas Water Heater Comparing Chart

Reviews Of Best 40-gallon Natural Gas Water Heater

1. Noritz EZTR40NG 40 gal Tank Replacement Indoor Tankless Water Heater  

natural gas 40 gallon water heater


This model is a natural gas-powered tankless heater that is the best solution when you’re switching from a tank-style over.

Useful features

  • Top plumbing connections for hassle-free replacement of tanked style heater
  • Valve kit included with 25 feet of polypropylene venting
  • K-Copper heat exchangers for fast water heating
  • Electronic ignition
  • Remote control thermostatic available but sold separately

This unit gives you an endless supply of hot water. It works ideally as a direct replacement for any existing 40-gallon tank-style water heater without additional expense and works for the plumbing. This is a moderately priced unit that is on the high end of the spectrum when it comes to quality, and you’ll have hot water on-demand.

2. A.O. Smith GCR-40 ProMax Plus High-Efficiency Gas Water Heater 

large 40 gallon gas water heater


This model is an excellent replacement unit for a tanked 40-gallon natural gas water heater. It offers a fast response time for the first heating and it keeps a steady flow of hot water on hand.

Useful features

  • Blue diamond glass coating
  • Self-powered electronic gas valve
  • Dynaclean diffuser dip tube
  • NAECA approved
  • Maximized hot water output system

What we love about this unit is that it is one of the more moderately priced units and it delivers on quality and performance. The Blue Diamond glass coating gives the unit a longer life and is resistant to corrosion. The electronic gas valve does not require additional power outside of the natural gas connection. It provides a continuous supply of hot water for your household needs. This unit has an internal microprocessor that enhances the sensing and quick heating response. The Dynaclean diffuser reduces the amount of maintenance needed by decreasing the buildup of lime sediment.

3. Bradford White 40 Gallon Natural Gas Water Heater  

40 gallon natural gas heaters


The Bradford White 40-Gallon is equipped with modern intelligent technology that gives you control over the unit. This is a high-performing system that lets you easily convert from tank-style water heating to tankless.

Useful features

  • Atmospheric Vent Safety System
  • Intelligent gas control
  • LED indicator lights
  • Built-in diagnostic tools
  • Maintenance-free

This model stands out with its advanced technology for enhanced safety. It comes with a thermopile converter to turn heat energy from the pilot flame into enough power to start the ignitor and operate the gas valve and microprocessor so you don’t need to have the unit near an electrical outlet. The Atmospheric Vent Safety System prevents harmful vapors from coming into contact with the flames. It also comes with LED indicator lights that signal when the pilot is on. there is also a diagnostic system built-in to let you know when there is a problem with a coding system for easy troubleshooting. This unit does not require any maintenance once it is installed. This is a moderately priced unit that is easy to install and will give an endless supply of hot water.

4. A.O. Smith XCRL-40 ProMax Short Gas Water Heater 

the best 40 gallon heaters


This tankless 40-gallon replacement natural gas water heater is another good value that is loaded with features for moderate pricing.

Useful features

  • Internal microprocessor
  • Tankless conversion replacement for 40-gallon tanked style
  • Dynaclean diffuser dip tube
  • Push-button ignitor
  • Built-in diagnostics tools
  • LED status indicators

What we like the most about this model is that it is a hassle-free replacement for a 40-gallon tanked natural gas water heater. The heating is fast and precise thanks to the internal microprocessor. This enhances its accuracy and speed. There is no need for an external electrical source because it operates from a thermopile technology and can operate solely on natural gas. The Dynaclean diffuser dip tube lowers the amount of lime buildup to make the unit last longer and require less maintenance. This is one of the more reasonably priced units that will continue to save money by reducing your power bill and giving you an unlimited supply of hot water.

How To Pick The Best 40-gallon Natural Gas Water Heater

Before you go out and buy a tankless hot water heating unit, there are a few things that you need to consider first. Tankless water heaters come with specific requirements that are not the same as storage based tanks. While most of these come with bottom mounts for the hot and cold water connections, there are some manufacturers who make them with the connections on the top. Take a look at your setup to make sure that you have the right setup, or make the necessary changes before you begin the installation. Buying a unit with the right connection placement can save you money.

best 40 gallon natural gas water heater tankless

Choose the right size

Size matters when it comes to tankless hot water heaters. Because it maintains a constant flow of hot water, you need to have the right size to heat the flow rate that will run your entire household. First, determine how many devices you will run and calculate the flow rate for each. Add up the gallons per minute that each uses. This gives you the flow rate to pick the right size heater. Here are a few examples to help: an average shower requires 2.6 gallons per minute unless you have a water-saving fixture.

Next, figure out the temperature rise.

This is done by subtracting the temperature of the incoming water from the output temperature you want to achieve. Most incoming temps are about 50 degrees F. Most families prefer water heated to between 105 to 115 degrees F so the rise would be approximately 55 degrees. If you run 2 showers at once, this would increase the number of gallons of water by double, and so you would perform the calculations according to how many gallons you plan to run at one time. You may want to do the same for sinks if they will be used at the same time. You must also check with your natural gas provider to ensure that you have enough pressure to ignite the unit you are installing and that there is a 120V power source nearby.

Quick Pick on the 3 Best 40 Gallon Natural Gas Tankless Water Heaters

Other Types of Tankless Water Heaters You May Like:


David: Penn State-educated Mechanical Engineer and Business-savvy Fluid Dynamics Specialist. Balances family plumbing business support with a thriving engineering career at a top, undisclosed company. (they want it that way) I help Will with plumbing and HVAC needs on his Real Estate.

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