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The Best 40 Gallon Gas Water Heaters for Your Family

Fact checked by Stephen Conklin

best 40 gallon gas water heater

A four-member family does not need a 100-gallon water heater for their hot water requirements. The best 40 gallon gas water heater is more than adequate, empowering households to enjoy significant cost savings over time. These devices heat water faster than electric units, and they continue running even in power outages.

People can study different parameters to decide which 40-gallon gas water heater to bring home. However, we examined hundreds of 40-gallon gas water heater consumer reports to understand how experts and ordinary people choose the perfect water heating appliance. Our research showed that three factors are crucial in determining the top-rated possible gas-powered water heater.

  • Type: Most people think a 40-gallon water heater is a storage-type system. However, there are also equivalent tankless water heaters, giving people an extra choice. In general, tankless gas water heaters are 24% to 34% more energy-efficient than conventional tank-type gas water heaters.
  • Water-heating Performance: Two things are crucial when picking a 40-gallon tank gas water heater – first-hour rating (FHR) and recovery rate (RR). A water heater with a high FHR and fast RR is better. On the other hand, tankless units should have a high gallons-per-minute (GPM) rating.
  • Warranty: Although optional, many people consider a product’s warranty when buying a 40-gallon gas water heater. A water heater with a 12-year guarantee is better than a six-year warranty unit. It underscores the gas water heater’s quality construction and performance.

There are more essential factors, which we will discuss in the comprehensive gas water heater buying guide that follows our product reviews.

Top 1

A.O. Smith ‎GCR-40

Dimensions 22 x 22 x 58.5 inches
Weight 165 Pounds
Material Glass, Copper

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Top 2

Bradford RG40T6N

Dimensions 20 x 20 x 60.5 inches
Weight ‎134 Pounds
Material Metal, Copper

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Top 3

EZ Tankless Water Heater

Dimensions 27 x 14.5 x 6.5 inches
Weight 31 Pounds
Material ‎Stainless Steel, PC

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Table of Contents

List of 8 Top-tier 40 Gallon Gas Water Heater Reviews

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

The A.O. Smith GCR-40 ProMax Plus High Efficiency Gas Water Heater, 40 Gal is one of the top-tier 40-gallon gas-powered units available on the market. It features advanced technologies to minimize, if not eliminate, the problems associated with conventional storage-tank water heater systems.

Although AO Smith 40 gallon gas water heater reviews give this product a four out of five, I still love it. This gas water heater delivers 70 gallons of refreshing hot water continuously for an hour. Families will never run out of water while showering and doing their chores.

I am surprised by its innovative technologies – a Dynaclean dip tube and a Blue Diamond glass lining. These elements give the gas water heater better protection against limescale and rust formation. People will never complain of reduced water heating capability due to scale buildup. Their water will also not taste like iron.

Controlling the water temperature is also a breeze because of its intelligent processor. Not only does it ensure ideal water temperatures, but it also does it quicker than other brands. Unsurprisingly, many homeowners love this high efficiency gas water heater 40 gallon unit. Operating and maintaining it is a cinch.

I appreciate its overall function, ensuring better cost savings for the budget-conscious household. A four-member family will only spend about $263 on their annual energy bills. It translates to exceptional savings the family can use for other purposes. The company is kind enough to offer six years of warranty on the water heater’s tank and parts.
  • 70-gallon first-hour rating
  • Scale and corrosion-busting Dynaclean dip tube and Blue Diamond glass lining
  • More cost-effective than other systems
  • Intelligent processor for quick and precise thermal control
  • Six-year warranty on tank and parts
  • Has bad instructions
Sadly, this water heater has subpar instructions that make installation difficult. Nevertheless, I strongly recommend this 40-gallon gas water heater for families with an existing natural gas supply. The energy and cost savings it brings are too good to ignore.

2. Bradford White RG240T6N 40 Gallon Water Heater

People looking for a skinny 40 gallon gas water heater should consider the Bradford White RG240T6N. This gas water heater measures only 20 inches in diameter, allowing families to install it in a small space. Although this option is slim, there is nothing insignificant about its advanced technologies.

I love its 76-gallon first-hour rating, enabling a family of four to enjoy a continuous hot water supply. Three people can take a shower, while another might run the dishwasher without causing the water to turn cold.

I also appreciate its recovery rate, heating the water to the ideal temperature within minutes. This gas water heater can deliver a 90-degree Fahrenheit rise within 43 minutes. Most products I know require at least an hour. This benefit is welcome news for households with high hot water demands.

As mentioned, this gas water heater comes with several technologies allowing it to deliver exceptional recovery and first-hour ratings. It has a factory-installed Hydrojet technology that works with the Vitraglas lining to prevent sediment, scale, and corrosion buildup.

Like the GCR-40, this gas water heater also features an intelligent microprocessor. I am glad the water heater has this feature because it makes operation and maintenance a breeze. It even has a Pilot ON indicator, eliminating the need to get down on one’s knees to check if the pilot light is operating or not.

Unfortunately, its Uniform Energy Factor rating is only 0.62. Although the rating is within industry standards for gas water heaters, I have seen products with higher UEF scores.
  • Delivers 76 gallons in the first hour
  • 43-minute recovery rate at a 90-degree rise
  • Advanced VitraGlas and Hydrojet technologies for corrosion and scale protection
  • Intelligent microprocessor for precise operation and convenient pilot indicator
  • Slim design for space saving
  • UEF is only 0.62
Nonetheless, I still recommend this water heater despite its flaw. Its technological features and skinny design make it an excellent water heater for a family of four.

3. EZ Ultra HE Natural Gas Indoor Water Heater

Although a 40-gallon storage-tank gas water heater is simpler to operate and less costly to maintain, it is not as energy-efficient as a tankless unit. It is also less suitable for households with cramped spaces. Hence, a family of four who wants to maximize their space and energy use should consider the EZ Ultra Tankless Water Heater.

This model is one of the top rated 40 gallon gas water heaters on the market, and for excellent reasons. People will never worry about installing this water heater in their tiny homes because it only measures 6.5 inches thick, 27 inches tall, and 14.5 inches wide.

Although small, this water heater packs a punch. I love its 3.4-GPM maximum flow rate. It raises the water temperature by 45 degrees Fahrenheit instantly. Taking one shower after another is never an issue because this water heater can accommodate high hot water needs.

I adore its advanced condensing technology that preheats incoming cold water to improve water heating efficiency. It translates to better cost savings while empowering families to control their energy expenditures. Its fully automatic operation ensures hot water will be ready without hassle, giving households peace of mind.

Most products do not work with low water pressures. This water heater does – at an incredibly low 8.0 PSI. Families will never worry about running out of hot water, regardless of how little water flows in their pipes.

Sadly, this tankless unit is a bit pricey. Moreover, it does not have testing certifications, which might deter some people from installing it in their homes.
  • Maximum flow rate of 3.4 gallons per minute
  • Cost-effective, automatic 40-gallon gas water heater
  • Advanced condensing technology for improved energy efficiency
  • Works with water pressure as low as 8.0 PSI
  • Space-saving design that increases water temperature by 45℉
  • No testing certifications
  • Not budget-friendly
Nevertheless, this gas water heater is excellent for families who want to replace their old storage-tank water heaters with a more efficient and space-saving device.

4. Rheem PROG40-40N RH62 Natural Gas Water Heater

I have a Rheem water heater which has served my family for countless years. Many households also trust this brand because of its reliable construction and dependable operation. That is what buyers get when they buy the Rheem PROG40-40N RH62. This slim 40-gallon water heater has all the right elements a family of four will want from a reliable gas water heater.

I love this gas-powered heater’s performance, capable of producing up to 90 gallons of hot water within the first hour. Families can wash their clothes and enjoy warm showers without worrying about the water turning cold.

Its 50.5-gallon maximum recovery rate is also commendable. This gas water heater can quickly raise the water temperature by 90 degrees Fahrenheit. The waiting is shorter than what other brands deliver.

Its energy efficiency and quick-heating capability come from the water heater’s 40,000-BTU rating. Not only is it fast in heating the water, this appliance is also more cost-effective than other products I know.

I commend Rheem for improving its sediment and scale buildup-prevention technology. The EverKleen system keeps the tank in pristine shape for many years. There is the R-Tech system, too, which aids in preventing limescale buildup in the tank. These two technologies can give families a fully functional water heater for at least a decade.

I also like its Guardian System, which automatically shuts off the device when it senses an air/fuel mismatch.

Sadly, its UEF score is only 0.58 to 0.66. Additionally, the company recommends expert installation, increasing the overall initial setup cost.
  • Up to 90-gallon first-hour rating
  • 5-gallon recovery rate at a 90-degree temperature rise
  • 40,000-BTU output for energy efficiency and cost reduction
  • EverKleen and R-Tech technologies for excellent tank protection
  • Advanced Guardian system for effortless operation
  • UEF rating is only 0.58 to 0.66
  • Expert installation recommended
Despite this, I trust this brand. I am confident many households do, too. It is a reliable water heating system for small families and people living in tiny homes.

5. A.O. Smith GPVL-40 ProMax Power Gas Water Heater

The A.O. Smith GPVL-40 ProMax Power Vent is one of the most affordable 40-gallon gas-powered water heaters anyone can buy. It has all the excellent features of the ProMax line, giving modern households exceptional savings in the long term.

I love this gas water heater’s first-hour rating, which is three gallons more than what the GCR-40 provides. That translates to a hot shower for another person in the home or another hour of washing duty.

I also like its new and improved DynaClean II dip tube that prevents limescale buildup. More importantly, the advanced technology optimizes water pressure to inhibit the formation of cold regions in the tank.

The two-inch thick insulating material is also denser than what other water heaters offer. Unsurprisingly, this design feature gives the GPVL-40 exceptional energy efficiency. Families will use only 214 Therms annually, compared to the GCR-40’s 242 yearly Therms consumption. There is an Energy Star certification to prove its claims, too.

Installation is also straightforward because of its three-position blower. Although this water heater is half an inch taller than the previous ProMax product we reviewed, its rotatable vent ensures hassle-free setups. It gives exceptional installation flexibility.

However, I find this water heater too heavy for comfort. I would have to ask two more people to assist in the installation.
  • Delivers 73 gallons in the first hour
  • Energy Star certification for power consumption
  • DynaClean II dip tube for limescale prevention and warm tank
  • Two-inch super thick insulation for better heat loss prevention
  • Three-position vent for added flexibility
  • Heavy, so multiple people may be needed to carry it
Regardless, I trust this brand. This gas water heater is not only more efficient than other 40-gallon gas-powered water heaters, but it is also cost-effective. The technologies it features are enough for homeowners to buy this gas water heater.

6. Camplux CA318 InstaHot Tankless Water Heater

Families looking to replace their old 40 gallon propane water heater should consider the Camplux CA318 InstaHot Tankless Water Heater. It has a power-saving mode, making this appliance an exceptional choice for energy-conscious homes.

Enjoying limitless hot water is never a problem with this gas water heater. It might have a tiny footprint, but it can deliver 3.18 gallons of hot water every minute. Its 82,000-BTU rating is more than twice what other gas tankless water heaters offer, producing 89.98% heating efficiency. It is an exceptional choice for families who want a quick-heating appliance.

This product may be the best price 40 gallon gas water heater. It will still be more practical than other products even if households decide to get expert installation. The savings people will get are great for other productive endeavors.

I adore this gas water heater’s multiple protective mechanisms. Users will never worry about the appliance overheating or freezing. It also has excellent protection against dry combustion, flame failure, low water flow, and high water pressure. I can go to bed confident that my house won’t go up in flames while I sleep.

I also love this gas water heater’s all-black, digital interface. It is like operating a smartphone, where all the menus and controls are available at a mere touch of the responsive screen.

Unfortunately, its ignition system requires an electrical connection. It would be best to get an electrician to set up the device.
  • 18 GPM maximum water flow and power-saving mode
  • 82,000 BTUs for 89.98% energy efficiency
  • Easy-to-use and elegant digital touchscreen control
  • Multiple protection systems for increased operational safety
  • More affordable than other gas water heaters
  • Requires an electrical connection
Overall, I’d pick this tankless gas water heater to replace conventional 40-gallon storage tank water heaters. Its energy efficiency is exceptional, and its versatility is superb. Safety-wise, this is the gas water heater that will never give homeowners the creeps.

7. Rinnai SENSEI SE+ RU180iN Gas Water Heater

There are many reasons why the Rinnai SENSEI SE+ RU180iN enjoys many positive 40 gallon gas water heater reviews. This is not an average tankless water heating device to replace an inefficient 40-gallon gas water heater. It is one of the best because of its remarkable construction, intelligent features, and exceptional energy efficiency.

I love this 40-gallon gas water heater replacement’s flow rate. People can use anywhere between seven and eleven gallons per minute. One can have three showers, a kitchen faucet, and a washing machine running concurrently without any hot water interruptions.

Its UEF value of 0.92 is also commendable, making it a high-end water heater. I love its Circ-Logic recirculation technology, ensuring on-demand, instantaneous water heating. Families will love washing clothes and dishes, taking warm showers, and enjoying other hot water-related activities.

I was dumbfounded to learn its durability can last up to twenty years or two times longer than conventional storage-tank water heater types. I am thankful the company provides a 15-year warranty for the heat exchanger and five years on other parts. I also love its WiFi compatibility, empowering users to monitor and control the water heater’s performance from anywhere in the world.

It is not surprising these features bump up the gas water heater’s price. Its footprint is also more substantial than other tankless gas water heaters I know. This product requires a space of at least 14.76 inches wide and 33.86 inches high.
  • Delivers 10 gallons per minute
  • 92 UEF score for energy efficiency
  • Advanced Circ-Logic recirculation technology for instant heating
  • 15-year warranty on heat exchanger and 5 years for other components
  • Two-decade durability
  • Compatible with WiFi
  • A high price
  • Not as compact as other tankless gas water heaters
Still, I will not hesitate to recommend this 40-gallon gas water heater replacement to anyone. Its biggest asset is the water heater’s energy efficiency, translating to better cost savings for the modern family. And if one gets the optional WiFi module, this water heater can make a smart home more intelligent.

8. Noritz EZTR40NG Indoor Tankless Water Heater

Many households consider the Noritz EZTR40NG the most favorite 40 gallon water heater replacement on the market. Not only is it suitable for a family of four, this gas water heater is also more efficient than traditional storage-tank water heaters.

I have seen many tankless water heaters, but few can compare to this product’s water heating performance. It delivers a maximum of 6.6 gallons per minute when most water heaters can only provide less than half this amount. It is the perfect solution for continuous hot water for the modern family.

Its energy efficiency is also higher than that of conventional tank systems. I appreciate its UEF score of 0.87. At least, families will never worry about unnecessary heat losses because of this appliance’s ingenious design.

I appreciate the company for using a K-copper heat exchanger system, which is more efficient than other materials. I also laud the water heater for having the connections on top. The design maximizes space and facilitates effortless installation.

I fell in love with this product’s 12-year heat exchanger warranty – a feature very few brands can match. It also covers its parts for five years and labor for one year. Households get peace of mind, knowing this gas water heater is an excellent replacement for their old and inefficient storage-tank gas water heater.

However, one cannot install it outdoors, unless one can ensure excellent protection against the elements.
  • 6 GPM maximum flow rate
  • UEF rating of 0.87
  • K-copper heat exchanger for efficiency
  • Top-mounted connections for easier installation
  • 12-year warranty on heat exchanger, 5 years for parts, and one year for labor
  • Not for outdoor use
Other than this concern, everything is top-notch about this gas water heater. It might not store 40 gallons of hot water, but it can deliver more hot water than a modern family can imagine. Its energy efficiency is excellent, and its warranty remains unbeatable. That is tremendous value for today’s homeowners.

What to Look for When Buying 40 Gallon Gas Water Heater


One must understand the different characteristics of a 40-gallon gas water heater to choose the most suitable product for the home. In general, 40-gallon units are ideal for small households with no more than four members. Although this appliance might work with a five or six-member family, the hot water consumption should be minimal.

Here are the essential elements buyers must look for in a 40-gallon gas water heater.


Although a 40-gallon gas water heater always includes a storage tank, some families might want to consider a tankless unit.

  • Storage Tank Water Heater

This gas water heater is the most common type one can buy on the market. It consists of a hot water tank with an integrated gas burner at the tank’s bottom. Gas provides the fuel for the burner to heat the water in the tank, allowing families to enjoy hot water when they open a faucet or shower.

Unfortunately, the stored water can lose its heat over time. Hence, the storage tank’s insulation is a crucial factor for these water heaters. Moreover, when one uses hot water, cold water enters the tank to replenish the water supply. Unfortunately, it can take some time to heat the water back to its ideal temperature.

  • Tankless Water Heater

On-demand, tankless water heaters are compact appliances that feature several coils. Coldwater goes through these parts, and a gas-powered heat exchanger raises the water temperature. Hot water goes out the other end whenever someone operates hot water fixtures.

A tankless water heater is perfect for families who do not use hot water devices simultaneously. Their compact design also makes these water heaters ideal for tiny houses or homes with limited spaces.

Heating Efficiency

In general, gas-powered water heaters are more energy-efficient than electric versions. Gas burners heat the water from all directions, leading to quicker heating times. However, gas water heaters have different heating efficiencies. It would be best to check a tankless water heater’s maximum water flow rate and a storage-tank water heater’s first-hour rating and recovery rating to determine efficiency.

  • First-hour Rating (FHR)

This value is an excellent indicator of a storage-tank water heater’s heating efficiency. It describes the number of gallons the appliance can deliver within the first hour of operation with a full tank. A good rule of thumb is to pick the water heater with a high FHR.

For example, a natural gas water heater 40 gallon unit with an FHR of 90 gallons is better than a propane gas water heater with an FHR value of 70 gallons. Both products can accommodate 40 gallons, but the natural gas version delivers more hot water in the first hour.

  • Recovery Rate (RR)

Storage-tank water heaters continuously replenish the water in the tank with cold water, heating it to the desired temperature. Unfortunately, it might take a while to reheat the water if the tank is almost empty due to high hot water consumption.

A water heater’s recovery rating describes its ability to reheat the water in the tank to the ideal temperature. The higher the RR of a water heater, the higher its heating efficiency is. For example, a unit with a 50-gallon recovery rate is better than a water heater with a 30-gallon RR.

  • Gallons per Minute (GPM)

Tankless water heaters do not have FHR and RR ratings. Instead, these appliances have GPM or the amount of hot water the device can deliver every minute. The higher the GPM, the more efficient the device is in heating the water. For example, a 10-GPM product is better than a 3.5-GPM water heater.


Great gas water heater manufacturers always stand by the quality and performance of their products. It would be best for buyers to examine a water heater’s warranty. Some brands only cover the heat exchanger for five years, while others cover it for 15 years. On the other hand, some gas water heaters might service the tank for ten to 15 years.

Buyers should analyze the coverage to determine for which parts or elements the company offers a limited warranty.

Unique Features

Companies try to outdo each other by incorporating advanced features into their respective gas water heaters. It would be best to examine these characteristics to decide whether they matter to you or not.

Intuitive technologies, low NOx operation, premium-quality gas valves, and LED indicators are some of the unique features one can see in modern 40-gallon gas-powered water heaters. While these attributes are welcome, buyers must understand that feature-packed water heaters often come with a hefty price.

Installation and Maintenance Ease

Most gas water heaters require expert installation because of the gas and exhaust requirements. Some products might also need professional electrical installation because of an electronic ignition system.

Buyers should consider ease of installation and maintenance when buying a 40-gallon gas water heater. After all, no one wants a complicated device to operate or a costly setup.

What Brand of Gas Water Heater Is the Most Reliable


A.O. Smith remains one of the most reliable gas water heater brands worldwide. Although established in 1874, this Milwaukee-based company started mass-producing water heaters in 1939. The brand continues its legacy of high-quality products to today, earning the trust of homeowners and commercial establishments globally.

Other trustworthy gas water heater brands include Rheem, Noritz, Bradford White, Rinnai, Camplux, and EZ Ultra.

How Much Should a 40 Gallon Water Heater Cost

A 40 gal gas water heater can cost families anywhere between $330 and $1,500. It can be more expensive if the household wants to replace a tank system with a 40-gallon-equivalent tankless unit. In such cases, the family might spend about $500 to $2,000.

The cost does not include labor and installation, which can set households back by $200 to $1,000 for a standard 40-gallon tank. If homeowners want to install a tankless replacement system, the overall cost can be $300 to $1,500.

People with plumbing and electrical knowledge can save a few hundreds of dollars if they install the gas water heater DIY-style. However, many things could go wrong during the setup. That is why many experts recommend getting a professional to install the 40-gallon water heater.

How Long Does It Take to Install a 40 Gallon Hot Water Heater

In general, replacing a 40-gallon water heater is faster and more practical than completing a new installation. A professional plumber can install a 40-gallon water heater within two to six hours, barring any mishaps and other untoward incidents.

Removing the old gas water heater should take about 45 minutes to an hour, while positioning and securing the replacement unit can take 30 minutes. Connecting the system to the power source and other elements can last 45 to 60 minutes.

However, gas water heaters with tanks require adequate ventilation and exhaust management. These requirements can extend the overall installation by at least another hour. If the water heater is in a tight space, such as a closet or attic, one can expect the labor time to increase.

How Long Should a 40 Gallon Water Heater Last

A 40-gallon water heater can last anywhere between eight and twelve years, depending on the brand and model. That is why a good indicator of the water heater’s service life is its warranty.

For example, a 40 gallon gas water heater 12 year warranty gives users confidence about the product’s longevity. They can rest assured the company stakes its reputation on the water heater’s quality and performance for at least a dozen years.

However, having a warranty does not mean one should be complacent. A few years before the water heater’s end-of-life, one can expect to see changes in water heating performance due to wear. People might notice leaks and reduced water heating capability in the tenth year.


The best 40 gallon gas water heater is perfect for a three to four-member household, giving families cost and energy savings they can use for other purposes. It is easy to operate, quick to heat, and delivers sufficient hot water for everyone. Such a unit lasts longer, too, enabling households to make the most out of their purchase.

People who remain confused about which 40-gallon gas water heater to buy can look at the products we reviewed in this article. They can also read our buying guide and find inspiration in our FAQs.

5/5 - (3 votes)