Plumbing, Water Heaters

Rheem vs. AO Smith: Which Water Heater Is Better

Rheem or AOSmith lg

A water heater in the home is an essential part of our daily lives. So it stands to reason that when you are putting in a new water heater, you want to make sure you are getting a good quality product! Two popular water heaters brands are Rheem and AO Smith. Both produce reliable water heaters, so which one would be the best water heater for your home?

Rheem and A.O. Smith both produce quality gas and electric water heaters. The difference comes in the range of units, availability, and price. Rheem heaters are more expensive but offer smart technology and solar options and are more widely available. AO Smith models are comparable in price and have a broader selection of gas water heaters.

When you replace your water heater, you should consider your purchase carefully since you are looking at a 10 to 12-year investment. While we are all interested in a good deal, you should make sure you are getting the best value for your money for this home appliance when it comes to a water heater.

You should be looking at several features of residential water heaters. Investigate how well Rheem and AO Smith water heaters fit these criteria.

What Features to Look for in a Water Heater

When you start your investigation into a new water heater for your home, you need to consider more than just the water heater’s capacity.

  • Energy-efficient water heaters. Your water heater can be responsible for up to 18% of your home’s total monthly energy cost. It’s beneficial to look for an energy-efficient water heater to reduce energy costs. Most water heaters will have an EF or Energy Factor rating, which indicates how energy efficient it is.
  • Size of the water heater. Most homes have a designated location for the water heater installation. When purchasing a new one, you need to make sure that the dimensions of the storage tank will fit in the designated location.
  • The capacity of the water heater. The water heater’s capacity is how much water it holds and can heat. Installing a smaller unit may mean that the heater cannot keep up with the demand for hot water in your home. The higher the water heater’s capacity, the more energy it will consume and the more physical space it will take up in your home.
  • The fuel source for the water heater. Some water heaters are gas-fueled, and some are electricity fueled. If you want to install a gas water heater, the room must have specific ventilation requirements before the installation is legal and safe. If your space does not meet these ventilation requirements for a gas-powered unit, you will have to stick with an electricity-powered water heater.
  • Reliability of the water heater. This is where brand consciousness may play a role in choosing a water heater. You want to invest in reliable brands with high-quality customer service and produce a quality product.

We will be looking at two popular water heater manufacturers and comparing the quality and reliability of their products to help you decide which brand will be the premium choice for your home.

Rheem vs. AO Smith Water Heaters

When seeking to understand a brand of any product, it is sometimes worthwhile to look at the companies’ roots and history to establish if they have a longstanding history and significant experience in manufacturing the products.

Both Rheem and A.O. Smith are American companies with a history in the USA that spans almost 100-years. However, both companies have very different beginnings.

Rheem started in the oil refining industry in Richmond, California, from 1862 to 1919. In 1925. Rheem was established and produced packaging material for the petroleum industry. In 1931, the company was bought by the John Wood manufacturing company, and it was at this time that they began manufacturing water heaters.

By 1941, the company had become the largest manufacturer of water heaters in the USA. Since 2007, Rheem Manufacturing Company has become a NASCAR sponsor for Richard Childress Racing.

AO Smith was founded in 1874 and was a baby carriage and bicycle manufacturer in those early days. They progressed to making glass-lined brewery tanks and, in 1960, began manufacturing water heaters. They were so successful in this field that they expanded to Europe in 1972.

This information shows that Rheem and AO Smith have a longstanding history in the manufacturing sector and have successfully manufactured water heaters. This speaks to the quality and the reliability of both brands of water heaters.

Water Heater

Are Rheem Water Heaters A Good Choice?

Rheem is considered one of the top brands in water heater manufacturing, and it is an excellent choice to purchase this brand to install in your home.

In addition to different standard tank water heaters models, Rheem also produces tankless water heaters and heat pumps. They have a wide range of products, furnaces, and air conditioning products.

The extensive range of capacity, power sources, tank, and tankless water heaters ensure that you will find a model in one of their ranges that will suit your requirements for a water heater.

Rheem Water Heater Energy-Efficiency

Rheem is a company that is dedicated to sustainability, and they are committed to contributing to the planet with the products that they create. As a result, they have dedicated much research and cost to energy-saving and energy-efficiency in their products.

Their goal in this regard has led to developing highly energy-efficient units and the production of combination or hybrid units that combine different fuel types in a single unit for greater efficiency.

As a result of their innovations in this area, Rheem water heaters offer some of the most energy-efficient units.

Rheem Water Heater Fuel Source

Because of its commitment to sustainability, Rheem has a wide range of differently powered water heating units.

They provide units powered by electricity, gas, solar power, and hybrid units that combine power sources to make a more efficient unit.

Rheem produces tank water heaters and has a range of quality tankless water heating solutions.

The hybrid units use a combination of gas and electricity to produce a water heating unit that is four times more efficient than a standard electric-powered water heater. This can translate into savings of around $480 per year in energy bills.

Of course, if you want to install a hybrid solution, you would need to have the required ventilation for the unit to cater to the gas component of the water heater.

Rheem Water Heater Reliability

Reliability is an aspect that Rheem has focused on as part of its sustainability drive, resulting in top-quality products with great longevity.

Rheem water heaters are sold through Home Depot and other select retail stores and feature a limited 5-year to 12-year warranty that covers select parts and tank leakage.

Their Marathon range of water heaters is marketed as the “last water heater you will ever buy” since it is made from durable plastics rather than stainless steel. This makes this model lightweight, making it easy to get into position when installing it in your home, and requires less reinforcement to support the water heater.

Rheem Marathon brand is an electric tank water heater with a limited lifetime warranty on the tank.

marathon water heater lg

Rheem water heaters have a reputation for reliability and longevity. A factor contributing to their reliability is that distribution centers for the units and spare parts are widespread, which speaks to their availability.

Availability Of Rheem Water Heaters

Considering that Rheem is one of the largest manufacturers of water heaters in the USA, it stands to reason that it has a high availability far and wide across the country.

This is a positive feature for this brand because the units are readily available, but replacement parts are also easy to obtain. In most cases, the water heater can be repaired rather than replaced, which cuts down on the cost of ownership for these units.

Availability is an important consideration to bear in mind when purchasing an item that can last up to 12-years or more. If you can be sure that spare parts will be available for the unit many years into the future, you will have peace of mind that your water heater can last well past this average lifetime.

Rheem Water Heater Convenience Features

The company’s innovative philosophy means developing “smart” water heaters that offer a new set of convenience features for what has been considered an install and forget appliance in the past.

The “smart” features are primarily implemented in their hybrid models and incorporate the following features.

  • Built-in WiFi. Built-in WiFi in the water heater allows you to connect to the unit via an app on your smartphone to control the water heater’s functions.
  • Leak detection and alert. The water heater will notify you of a possible leak and automatically shut off water valves to prevent water damage.
  • Scheduled water heating. You can program the water heater to produce hot water in your home when needed and go into low production mode during low use times of the day.
  • Away mode. Program your water heater to go off during an extended absence from your home and switch it on before your arrival to have hot water when you get home.
AOSmith lg

Are A.O. Smith Water Heaters A Good Choice?

A.O. Smith is also a producer of quality water heaters. Many people who have dealt with the company and installed these units in their homes have good reports on these units that endorse their commitment to producing quality water heaters.

A.O. Smith water heaters manufacture a quality water heater product and are often recommended by many plumbers and plumbing supply companies.

Unlike Rheem, AO Smith is solely focused on water heater production and is expanding its network worldwide.

A.O. Smith water heaters are certainly a good choice for heating the water in your home.

A.O. Smith Water Heater Energy-Efficiency

The years that A.O. Smith has in the history of manufacturing and designing water heaters have given them time to tweak their designs to the point that they produce highly energy-efficient water heaters.

While each heater model in the range has different energy factor ratings and should be checked for each model, the A.O. Smith water heaters generally have the edge in energy efficiency over similar Rheem models, particularly in the electricity-powered models.

However, this energy efficiency gap between the two manufacturers is marginal, and in some models, the Rheem units out-perform the A.O. Smith models.

You would need to compare similar models from both manufacturers to establish which better EF rating.

A.O. Smith Water Heater Fuel Source

A.O. Smith makes models of water heaters powered by gas, electricity, and hybrid models, which combine different heating fuel sources for cost efficiency.

Like Rheem, A.O. Smith produces a wide range of water heaters powered by different power sources.

A.O. Smith has an option for natural gas-powered units and propane gas-powered units, which gives a little more versatility in the choice of gas fuel. In addition, A.O. Smith has a broader range of models in the gas-powered water heaters than what Rheem offers.

A solar water heater option is the one type of water heater that A.O. Smith does not produce. Therefore, if you are looking for an off-grid water heating solution for water heating, you would have to look at a product from a different manufacturer.

AO Smith Water Heater Reliability

The water heaters produced are made from quality components that result in a product with a long lifespan. Many people who have an old A.O. Smith water heater look to replace it with the same brand because of this manufacturer’s proven reliability of the water heaters.

AO Smith Signature Series water heaters are sold through Lowe’s, while the AO Smith ProLine models are available through local plumbing contractors. Water heaters feature a limited 3-year to 12-year warranty covering select parts and tank leakage.

The only difference between A.O. Smith and the Rheem products in this department is that Rheem is more widely distributed than A.O. Smith products and parts.

AO Smith tankless heaters are produced through a joint-venture partnership with Takagi. In 2020, AO Smith took over the management of Takagi’s existing North American sales and distribution organization, maintaining Takagi’s North American headquarters in Irvine, Calif.

For more, see Takagi Tankless Water Heater Review.

ao smith takagi lg

A.O. Smith Water Heater Availability

AO Smith water heaters are available in most major centers around the country, making them accessible if you live near a large city.

They also have a range of signature water heaters that Lowes solely distributes, so if you have a Lowes store near you, you can find a supply of AO Smith water heaters and parts for these models.

AO Smith also has a subsidiary brand known as American. Read our American Water Heater Review (6 Helpful Tips).

Summary & Price Difference for Rheem vs. AO Smith Water Heaters

Rheem and AO Smith water heaters are quality products, and either one would be a good choice for your home. There is no clear winner, only what works best for your individual needs.

Both brands have similar types of water heaters and warranties. A slight edge would go to Rheem for a larger product line and availability of replacement parts. However, that’s not to say AO Smith doesn’t also excel in this area.

The main difference between these two top brands is the product availability. Both would be suitable for your needs, with no better than the other in longevity and performance.

If you want to choose a greener option and go with the solar water heater option, you would have to go with a Rheem unit. On the other hand, if you want the convenience features to incorporate into a smart home design, the Rheem hybrids, with their electronic components, would be the unit to choose.

When it comes to price, the AO Smith units are generally better priced than the Rheem units, which is why many people consider them to be more value for money.

The final aspect is accessibility. The Rheem brand is distributed more widely than the AO Smith brand, which means your locality may dictate which water heater brand is easiest to obtain.


  • Gas water heater models: AO Smith – due to a broader range of models and years of experience in gas water heater production.
  • Electric tank water heater models: Rheem – Rheem appears to be the more widely available worldwide. However, AO Smith is a better choice based on cost alone. Both have nearly identical lifespans.
  • Heat Pump Water Heaters: Rheem – we lean Rheem here, mainly due to the company having experience manufacturing and developing heat pump technology.
  • Gas tankless water heaters: Rheem – we leak Rheem here as well. AO Smiths’ market share for tankless water heaters is much smaller than Rheem’s, affecting the availability of replacement parts.
  • Consumer Reports: doesn’t rate one brand higher than the other.
  • Customer Service: AO Smith – from our research, we’ve found better customer experiences with AO Smith over Rheem. A large segment of AO Smith products is sold exclusively through plumbing contractors. Rheem is primarily sold through big box stores and many homeowners install it themselves. Because of DIY installation mistakes, customer complaints are higher with Rheem over AO Smith.

Ultimately, we thank Rheem is better than AO Smith, but not by much. Both are top brands and produce high-quality products.


Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.