A.O. Smith Water Heater Reviews (2021 Guide)

A.O. Smith is a top water heating brand, here’s why you might choose a unit.

Looking for a new water heater but not sure which brand to choose? Ever heard of A.O. Smith? Today we’ve put together a complete A.O. Smith water heater review.

A.O. Smith has a long history — the company introduced a lot of the innovations that make today’s water heaters so efficient. We can’t talk about water heaters without mentioning the name A.O. Smith. So let’s have a look at their history and best products.

Our Top Picks

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Product Comparison Table

Product Image of the 50 Gallon Voltex Residential Hybrid Electric Heat Pump Water Heater
Best Hybrid
A.O. Smith Voltex® Hybrid Electric Pump
  • Features 4 energy-saving settings
  • User-friendly digital display
  • Heavy-duty anode rod & heating elements
Product Image of the AO Smith ATI-540H-N Condensing Residential/Light Commercial Tankless Heater
Best Tankless
A.O. Smith ATI-540H-N Tankless NG
  • Commercial-grade copper alloy
  • NOx regulation complaint
  • Freeze & overheat protection
Product Image of the A.O. Smith GPVL-50 ProMax Power Vent Gas Water Heater, 50 gal
Best Gas
A.O. Smith GPVL-50 ProMax
  • Features a hot-surface igniter
  • Glass-lined tank
  • Internal dip-tube feature

Why Choose A.O. Smith Water Heaters?

One thing we really appreciate about A.O. Smith is that they go all out to help customers find the perfect unit. There are several tools available on the official website to help you find the right water heater.

If you’re looking for a specific type, A.O. Smith has a wide choice for both residential and commercial use.

Which A.O. Smith Water Heater Should You Choose?


A.O. Smith’s ProLine water heaters are a great fit for larger households or those living in colder regions. The company also says they are designed as a good choice for a mobile home.

These water heaters have an incredibly high recovery rate, with a first-hour rating of 79 gallons per hour. Most will have a uniform energy factor of .70 percent or more. Many are even Energy Star certified.

That said, this line isn’t as high-tech as some of A.O. Smith’s other products. The ProLine water heaters don’t have Wi-Fi compatibility or include any other high-tech functions.


A.O. Smith has two lines of tankless water heaters: gas/propane and hybrid/propane. It seems, however, that gas/propane is the favorite among users.

Most of the gas/propane models are still Energy Star and LEED-certified. They all have Ultra-Low NOx ratings and are highly efficient.

Depending on the size of your unit, they can provide you with an endless flow. These are a great addition to a three-bathroom home.


A.O. Smith’s hybrid water heaters adhere to their Voltex line. These are a cross between their electric Vertex line and hybrid design.

All their models within the Voltex line are Energy Star certified. They all feature the benefits of an electric boiler with the efficiency of a heat pump design. This results in a money and energy saving match.

The Voltex hybrid water heaters also work as dehumidifiers, drawing moisture from the surrounding air. Once inside the unit, this moisture is used to heat the water. This, in turn, reduces water consumption and running costs.

With that said, these units do require some space to work. If your house is on the smaller side, this line probably isn’t for you.

The Best A.O. Smith Water Heaters of 2021

A.O. Smith, being one of the innovators in the water heater industry, finding suitable products wasn’t a problem. Narrowing them down to the top three, though? A whole other issue.

Researching good water heaters, user feedback, and obtaining expert advice, we managed to find our top three.

1. A.O. Smith Voltex® Hybrid Electric Heat Pump Water Heater

Best A.O. Smith Hybrid Water Heater

Hybrid water heaters are the dream appliance for any homeowner looking to reduce their utility costs. Today we’ve chosen the Voltex 50-gallon electric heat pump water heater.

When it comes to cutting costs, this model delivers. A.O. Smith claims that it can reduce your water heating costs by up to 73 percent.

It features advanced technology which pulls the surrounding heat in, all while dehumidifying the remaining air. This, in turn, cools down the room.

One thing we love about hybrids is their multiple useful settings — the Voltex is no exception. It has hybrid, efficiency, vacation, and electric modes. You can change the setting on the fitted digital screen which also shows and lets you choose the temperature.

The digital display is very user-friendly — with fewer buttons, there’s less chance of a mishap. Another useful feature is the heavy-duty anode rod. This will, reportedly, keep your tank safe for up to 10 years.

This hybrid can provide enough hot water for two simultaneous showers. Thanks to its two heating elements, the unit also has a relatively quick recovery time of 66 gallons per hour.


  • Highly efficient.
  • Features four energy-saving settings.
  • User-friendly digital display.
  • Includes a heavy-duty anode rod and two heating elements.


  • Louder than other hybrids.
  • Might not be as effective in colder regions.

Additional Specs

Uniform Energy Factor 3.45
Recovery rate 66 gallons per hour
Measurements 63 inches by 22 inches by 22 inches
Energy Star Rated Yes
Warranty 10-year limited warranty on tank and parts

2. A.O. Smith ATI-540H-N Tankless NG Water Heater

Best A.O. Smith Tankless Water Heater

If you have a larger household and are looking for a space-saving alternative, we may have found one for you. A.O. Smith’s 540 series is excellent for residential use. Today we chose the ATI-540H-N tankless water heater.

Similar to the rest of the 540 series, this model utilizes commercial-grade copper alloy in its heat exchanger. This durable material is also what makes it sufficient for a higher-demand household. It delivers an unlimited amount of hot water for three to four running bathrooms, depending on your climate.

The unit runs on natural gas and uses no more than 199,000 BTU an hour. It’s compliant to the Ultra-Low NOx regulations and has a uniform energy factor of 0.93. It works with condensing technology, making it super-efficient.

The incorporated safety features include overheat and freeze protection, as well as troubleshooting codes. It also comes with an Easy-Link System, meaning that you can connect it with up to four other units.

This tankless water heater is also fairly easy to install. Although A.O. Smith recommends that you mount it indoors, you can install it outdoors as well. But keep in mind that outdoor installation is only recommended if you live in a warmer climate.


  • Heat exchanger fitted with commercial-grade copper alloy for durability.
  • Unit is compliant to the Ultra-Low NOx regulations.
  • Includes safety features such as freeze and overheat protection.
  • You can install it indoors or outdoors.


  • Flow sensors require a higher flow to activate which may result in cold water.
  • Quite loud while working.

Additional Specs

Uniform Energy Factor 0.93
Recovery rate 10 gallons per minute
Measurements 23.625 inches by 17.75 inches by 11.25 inches
Energy Star Rated Yes
Warranty 15-year heat exchanger warranty and five years on parts

3. A.O. Smith GPVL-50 ProMax Power Vent Gas

Best A.O. Smith Gas Water Heater

A.O. Smith’s gas water heaters work either on natural gas or liquid propane. We chose to show you the GPVL-50 ProMax, part of their ProLine series.

This unit is excellent for the household with a higher demand for hot water. It’s fitted with several useful features and functions, one of which is the internal dip-tube.

Cold water enters through the dip-tube, which reaches down to the bottom of the tank. Here it puts pressure on the cold water, inhibiting it from influencing the temperature of the heated water. This results in less energy wasted on reheating.

To save further energy, the unit has a hot-surface igniter as opposed to a pilot light. A hot-surface igniter is generally more reliable and robust than its pilot cousin.

The tank itself is also quite durable. Instead of the usual steel tank, A.O. Smith lined theirs with glass — eliminating the risk of rust and corrosion. To top it all off, they insulated it with a 2-inch environmentally-friendly foam. This will minimize standby heat loss.


  • Delivers enough hot water for a five-person household.
  • Features a robust hot-surface igniter.
  • Glass-lined tank with 2-inch environmentally-friendly foam insulation.


Additional Specs

Uniform Energy Factor 0.72
Recovery rate 79 gallons per hour
Measurements 60.1 inches by 24 inches by 24 inches
Energy Star Rated Yes
Warranty Six-year limited warranty on tank and parts

History of A.O. Smith

A.O. Smith is one of the oldest leading water heating companies. It was founded by Charles Jeremiah Smith in 1874, but they didn’t initially manufacture water heaters.

A.O. Smith started out manufacturing baby carriages and bicycles. They worked at forming steel tubing from sheet metal to create frames for different products. Two decades later, they became the biggest bicycle part manufacturer in North America (1).

In 1899, A.O. Smith began making frames for cars. Son of Charles Jeremiah Smith, Arthur Oliver Smith, created the first pressed steel vehicle frame.

They soon began making frames for car manufacturers such as Cadillac, Peerless Automobile Company, and Ford Motor Company.

World War Efforts

During the First World War, A.O. Smith engineers developed a coated welding rod. Their breakthrough became a great influence on the development of arc welding as a mass-production method.

A.O. Smith continued to produce military equipment during the Second World War. The company produced 16,750 sets of landing gear, 46,700 propeller blades, and even nose frames for B-25 bomber planes.

They also built 4.5 million bombs, water heaters for barracks, and jeep frames. They even took part in the atomic bomb project in 1945 by building various components (2).

Water Heater Developments and Expansions

Soon after the Second World War, A.O. Smith acquired the Burkay Company of Toledo, Ohio. It was here that they officially entered the market for coil-type commercial water heaters. Five years later, A.O. Smith introduced the world to the first glass-lined commercial water heater.

At the beginning of the 1960s, A.O. Smith International opened a commercial water heater and boiler plant in Stratford, Canada. This would become the company’s first water heater plant outside of the United States.

The 1970s became a decade of much success for A.O. Smith. In the early 70s, they expanded to Europe, building a plant in Veldhoven, Netherlands. Initially a sales office for Europe and the Middle East, this soon included assembly and fabrication premises.

In 1974, A.O. Smith celebrated its 100th anniversary. It also introduced its Conservationist line of residential water heaters (3).

One of A.O. Smith’s great expansions happened in 2001 when it acquired State Industries, Inc. This almost doubled the size of the A.O. Smith water heater business.

The company made another huge acquisition in 2007 when it bought GSW Inc. and the American Water Heater Company.

A.O. Smith would soon add Whirlpool and John Wood brands to its name. Essentially, making it one of the largest water heater companies in North America. In 2008, the company became one of the first U.S water heating companies to market units in India (4).

In 2010, A.O. Smith joined forces with Takagi Industrial Company. Both companies made an agreement that A.O. Smith would acquire the North American operations of Takagi. They would join each other to manufacture and market tankless water heaters in North America (5).

Today, A.O. Smith is focusing on bringing its customers clean water through its many water treatment products. The company recently unveiled a new center in Milwaukee — the L.R Smith Corporate Technology Center.

Here, engineers use advanced research to develop portable and hydronic water heaters. They also carry out water treatment and air purification (6).

Where to Buy A.O. Smith Water Heaters

If you wish to purchase an A.O. Smith unit, you can do this through its official website, hotwater.com. You can also find a wide range of choices on Amazon.

A.O. Smith Customer Service and Reviews

You can contact the A.O. Smith customer service directly through its website. Forms are available online to inform them of any issues. You can also find relevant email addresses and phone numbers, including international numbers for anyone purchasing outside of the U.S.

Customers can find manuals, catalogs, and spec sheets if needed. The website also features a Product Selector Tool which helps consumers to find the right unit for them. You simply answer a few relevant questions and the tool will pick out a list of products and their prices (7).

One of the many things customers are praising A.O. Smith for is the great quality of their products. Although a few have received faulty units, customer service was quick to replace them.

Ao Smith Water Heater Comparison Chart

Product Award Uniform Energy Factor Recovery rate Measurements Energy Star Rated Warranty
Voltex® Hybrid Hybrid 3.45 66 gal/hr 63″ x 22″ x 22″ Yes 10-year (limited)
ATI-540H-N Tankless 0.93 60 gal/hr 23.625″ x 17.75″ x 11.25″ Yes 15-year (heat exchanger); 5 years (parts)
GPVL-50 ProMax Gas 0.72 79 gal/hr 60.1″ x 24″ x 24″ Yes 6-year (limited)

Are They Worth It?

A.O. Smith has a long history of leading the way with innovative technology and design. Their products, however, don’t seem to be very highly rated on big sites such as Amazon or HomeDepot.

Fortunately, though, their own website is easy to get advice or shop from.

We love this company, especially because they have a water heater for every different demand. We hope that you enjoyed our A.O. Smith water heater review. Do you have one of their units? Please let us know in the comments below.

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About the Author

Peter Gray

Peter has been a homeowner for 35+ years and has always done his own repair and improvement tasks. As a retired plumber, Peter now spends his time teaching others how they can fix leaks, replace faucets, and make home improvements on a budget.