The 40-Gallon gas water heater is the most found water heating system across the world. It is the perfect size for most families, and the durability of a gas water heater is something that everyone can appreciate.

Best 40 Gallon Gas Water Heater

If you are looking for minimal maintenance and a reliable, durable natural gas water heater, then finding the best 40-Gallon gas water heater should be important to you. There are many options to choose from, and there are factors that should be considered by every homeowner.

Throughout this article, we will highlight the important characteristics of the natural gas water heater and point out to you several things that should be considered when choosing the perfect 40-Gallon gas water for you.

Everybody will have different requirements and limitations due to their specific family size, space availability, and installation requirements. Still, we are confident that there is a 40-Gallon water gas water heater that will work for you.

Difference Between a 40-Gallon and 50-Gallon Water Heater?

Overall, you will see two main differences between 40 and 50-Gallon gas water heaters. They both have the same technology and the same purpose; the only main difference is size and capacity.

Many times, the BTU output will remain steady between the two size variations, and the sediment combatting features will also be uniform between the two sizes.

As mentioned, two areas are distinguishable that are important to understand. The size of a 40-Gallon gas water heater tank is much easier to maneuver and fit into more spaces for installation.

In terms of the 50-Gallon water heater, you will see more water available upfront and the first-hour rating will typically be more, although this should not be a deciding factor unless you have a VERY large family.

40-Gallon Gas Water Heater

Easier Installation

The beauty of the 40-Gallon water heater is that you can fit them into tighter spaces much easier than a 50-Gallon gas water heater. With the standard water heater that comes with a tank, one of the biggest complaints is that they are tough to fit into some homes.

They are bulky, wide, and heavy. Because of the smaller capacity in a 40-Gallon gas water heater, you can slide it into more spaces and not be as limited in your choices.

One of the most important aspects of the tank-style water heater installation is the height. There are vent pipes, water pipes, and gas lines running around, and if you have a wicked tall water heater, you will be limited there as well. Because most 40-Gallon natural gas water heaters are considered, “Short” water heaters, they are easier to fit vertically into space.

50-Gallon Gas Water Heater

First Hour Rating and Capacity

The biggest difference between a 40 and 50-Gallon natural gas water heater is the water capacity, and most notably, the first-hour rate. This rate refers to the amount of hot water available in the first hour the machine is running, assuming the tank is full.

For bigger families, a 50-Gallon water heater makes it easier to accommodate all the members of the family and the water that they demand daily. The typical family of 4 will have more than enough water capacity with the best 40 Gallon gas water heater, but the added capacity of a 50-Gallon water heater makes it better for families with 5 or more people.

Is a 40-Gallon Water Heater Enough?

This depends entirely on the size of your family and the amount of hot water that is used daily. There are far more appliances throughout the home that rely on hot water than many people realize, but the reality is, these appliances are not run every day and they also use much less water than the shower.

For MANY homes, a 40-Gallon water heater is more than enough to handle the typical capacity of many homes.

The first thing you need to consider is the number of people in your home. Obviously, the more people in your home, the hot water demand will be higher.

I always suggest to my clients that if you have four or fewer people in the home, a 40-Gallon water heater is more than enough, and the benefits from the smaller tank will benefit you more than having water you capacity you do not need. If your water demand is higher or you have 5+ people in the home, you may want to consider a larger gas water heater.

40-Gallon Gas Water Heater Prices

Another benefit of the 40-Gallon natural gas water heater is the up-front cost associated with it. They are far more affordable than larger capacity water heaters, but it is important to remember that with gas water heaters in general, they are more expensive than their electric counterparts.

However, the operating costs of gas water heaters are much less than electric water heaters and outweigh the up-front savings in most cases.

Depending on the BTU maximum rating and the quality of the valve, you will see a lot of variation in prices for 40-Gallon natural gas water heaters.

The water heater is one of the most important home appliances, and you will be highly surprised by how often you rely on your water heater.

Finding the perfectly priced water heater for you is important, but there are numerous safety features that you will find in the higher-priced 40-Gallon gas water heaters that are worth it for most homes.

How long to heat 40-Gallon gas water heater?

The time associated with heating the water in a 40-Gallon gas water heater can be dictated by the BTU rating that comes with a gas water heater. The British Thermal Unit (BTU) rating of 40-Gallon gas water heaters is typically around 34,000 BTUs. A higher BTU rating means that there is more power associated with the burner, and the important part is that it will heat up faster.

Because the gas water heater is typically slower to provide hot water than a tankless system or electric system, having a higher BTU rating will allow for less wasted water between turning the water on and having hot water be delivered.

You will also want to check the type of burner that the water heater possesses. Systems that have a pilot light will heat up slower and can also cause longer wait times between a hot water valve being opened and the delivery of the hot water. We suggest finding a unit that has surface ignitor. We find they are quicker to heat, are safer, and require less maintenance.

Best 40 Gallon Gas Water Heater Reviews

1. A.O. Smith GCR-40 ProMax Plus 40 Gallon Gas Water Heater

A.O. Smith GCR-40

A.O. Smith is one of our favorite brands of water heating systems. They constantly strive to include small, user-friendly details that will give you peace of mind that your water heater will be there for you when you need it.

This 40-Gallon gas water heater is a tank; it so strong and durable that I have no worries when it comes to durability with this system. While the tank is very heavy, once it is in place, you will not have to worry about it anymore.

It runs extremely quiet for a 40-Gallon gas water heater, and the efficiency certification from the NAECA gives me peace of mind knowing I am not wasting energy or water. This natural gas water heater is great for any home, but it would excel in an area that has a water supply that is on the harder side.

The glass-lined interior helps combat corrosion, and the Dynaclean diffuser fights off limescale build-up and sediment issues.

Why We Love It

  • There is a microprocessor that allows for precise temperature sensing and faster heating response.
  • The relief valves and spigots are all made from brass, which is the best material for durability.
  • Thanks to the Dynaclean diffuser dip tube, there is hardly any sediment or lime buildup.
  • Since this model is a direct venting model, it draws clean air from the outside environment to help ventilate gas.
  • For a gas water heater, we were very impressed by the low noise level with the A.O. Smith System.

Keep In Mind

For a 40-Gallon heater, it is VERY heavy and hard to maneuver.

2. Bradford White 40 Gallon Natural Gas Water Heater

Bradford White 40 Gallon

The Bradford White 40-Gallon natural gas water heater is one of the more reliable gas water heaters on the market today. One thing that this company does is keep things simple.

If you are looking for something flashy or loaded with unnecessary technology, then you may want to look another direction. But, if you prefer reliability and quality, you are in the right place. The Bradford White is a no-thrills water heater that provides you with consistent hot water.

Every component of this gas water heater is made from brass or stainless steel and is heavy-duty. I have not once had an issue with the durability of the components on this gas water heater.
One of our favorite features of this 40-Gallon gas water heater is the LED-Indicator light.

Many times, lesser models will have an LED-light indicator to identify error codes. But they are often hard to understand, or the light is just simply not bright enough. With the Bradford White model, the green LED is bright, and the error code cadence is easy to identify.

Why We Love It

  • All the water connectors and valves are metal, which is great for durability.
  • The LED status indicator is easy to see and the cadences are easily distinguished.
  • There is a resettable thermal switch that helps with safety when there is a flammable vapor present.
  • The sight window that allows you to view the ignitor and thermocouple is wide and easy to open and close when servicing the unit.
  • This natural gas water heater is very quick to respond to hot water requests within the home.

Keep In Mind

We notice that the tank with this unit dents easier than some other comparable systems.

3. Noritz EZTR4ONG 40 Gal Indoor Tankless Water Heater

Noritz EZTR4ON

The Noritz Tankless water heater was truly ahead of its time. With a maximum water capacity of 6.6 GPM, this is one of the most popular 40-Gallon gas water heater replacements out today.

There are many benefits that you will see right away with this tankless gas water heater, but the most noticeable thing is the noise level.

Standard 40-Gallon gas water heaters can be extremely loud, especially if they require power venting exhaust. With the Noritz system, you will not hear a thing, and for the first few weeks you have it, you will be wondering if it is running.

While this unit is very heavy for a 40-Gallon gas water heater equivalent, you will not have to worry about durability.

All the components are solid, and you will not see any plastic components either.

The beauty of the tankless water heater is that you will never run out of hot water and the Noritz proves this theory right away.

Why We Love It

  • Compared to other 40-Gallon natural gas water heaters, this tank is much lighter!
  • The gas valve is quick-reacting and has safety features to ensure no excess gas remains in the unit.
  • Multiple features within this system help fight tank corrosion, which we appreciate.
  • There is hardly any maintenance with this gas water heater.

Keep In Mind

The pilot light ignition was tricky to get lit, but eventually, we got there.

4. Rheem PROG40-38N RH59 Natural Gas Water Heater

Rheem PROG40-38N

The Proline 40-Gallon gas water heater is a popular choice for many homeowners, especially those who have more complicated venting pipes.

Often, condo buildings and apartments will have water heaters that are placed in precarious spots making it very difficult for gas to be expelled properly.

To combat this, the Proline XE features a powered exhaust fan that pushes gas out with strong force rather than the atmospheric style we have seen. This exhaust fan was quiet and kicked in immediately, which we were impressed by.

The tank itself features a few features that help combat water hardness and sediment buildup. These are great to have because you will have overall better water, and they will elongate the gas water heater.

All the components are made from brass, which is the best choice for durability and its ease of use. Plastic valves can get stuck easily, and with this brass valve, it features ¼-inch flathead screw that allows you to tighten and loosen the valve easily. With this, you could accidentally bump the valve, and it will not open, causing unnecessary leaks!

Why We Love It

  • This gas water heater has a hot surface ignitor rather than a pilot light and it is much more reliable.
  • The drain valve is made entirely from brass, which is always more preferred than plastic.
  • There is a self-cleaning dip tube that prevents the buildup of sediment and limescale.
  • The anode rod is sacrificial and does a great job of reducing hard water levels within the tank.

Keep In Mind

The warranty is 6 years, which is lower than many other 40-Gallon water heaters.

Frequently Asked Questions & Answered

How many BTU is a 40-Gallon gas water heater?

The BTU-rating will vary between 40-Gallon gas water heaters.
The most common BTU-rating is 34,000, but you will find many options that have a higher maximum output. This will usually make the unit slightly more expensive, but the benefits will typically outweigh the up-front costs.

How long can you shower with a 40-Gallon water heater?

To determine the length of the shower, you must investigate the water heater’s first-hour rating or FHR. This number refers to the amount of hot water that the water heater can produce in the first hour it is running.

It is important to understand that the first-hour rating assumes that the tank portion of the water heater is full. The higher the FHR on a specific unit, the longer your showers will last. The average shower uses 2.1 gallons of hot water per minute. To determine the exact amount of time, you will be able to shower comfortably, divide the first-hour rating by 2.1.

Is a 40-Gallon gas water heater enough for a family of 4?

Yes! This is the perfect size for a family of 4. 40-Gallon gas water heaters are more affordable to run when compared to larger models, and the amount of water that a 40-Gallon water heater can produce is more than enough for a typical family of 4.

Assuming each member of the family takes a standard 8-minute shower, you have enough water to handle all four showers at one time!


Natural gas water heaters are still one of the most popular water heating choices in the world.

They are reliable, cheap to operate, and run, and are the most durable option on the market.

Finding the best 40-Gallon gas water heater is a different process for everybody involved, but once you’ve decided that the 40-Gallon capacity is right for you, now it is time to determine the functions features you wish to have.

By following our review guide and in-depth buying section, we are confident that you have all the information you need to determine the perfect 40-Gallon water heater for you. We sincerely thank you for tuning into this article, and we wish you all the best in finding the best 40-Gallon water heater for you.