Rheem vs AO Smith

Rheem vs AO Smith: Which Is Better?

In the United States, Rheem and AO Smith are two of the most popular water heater companies. Both of the companies offer a variety of different water heaters for bigger and smaller households.  Their water heaters are powered by gas and electricity, but which one is the best for your household?  They offer both tanked and tanked.  

Tank or Tankless—the Difference

Tank:  This water heater is insulated and holds 30-50 gallons of water.  It will fill and always maintain a certain amount of hot water even if it is not in use.  If the tank runs through its stored hot water, you will get cold water.  The reason is that it takes time to refill and then bring the water to the set temperature.

They are less expensive to install and simple to operate.  The disadvantages are you may have a higher energy bill, they only last 10-15 years, which is about half the time of tankless water heaters.  They also use 24% to 34% more energy than a tankless one.

Tankless:  This is a water heater that heats water instantly as it flows through the device.  It does not retain any water internally except for what is in the heat exchange coil.  They can be installed throughout a home at more than one point-of-use.  

The one advantage of this type of water heater is that there is a continuous flow of hot water along with potential energy savings; they use about 35% less energy.  The tankless water heaters are also a little smaller and will take up less space in your home.  The water is also fresher and cleaner.  They do cost more for the equipment and installation than a tank water heater. 

Rheem Hot Water Heaters

This company has been offering their water heaters for almost 100 years with a variety of water heaters that are not only practical but also of high quality.  This company is a major player in the United States in the market for Electric Tankless Water Heaters.

Their water heaters were introduced to households around the end of 1925 and from the beginning, they thought about their customer’s satisfaction.  They also introduced many innovative models with unique features.  With their electric water heaters, they have a simple installation method.

Gas:  They offer approximately 43 gas water heater models and are found in about 22% of households.  One gas tank model is the Rheem PROG40-38N RH59.  This model measure 20 x 20 x 50 inches and weighs 130 pounds and holds 40 gallons with a warranty of six years

Electric:  A tankless best seller is the Rheem 240 V Heating Chamber RTEX-13 Residential Water Heater.  It measures 4 x 9 x 13 inches with a voltage of 240 and 13 KW wattage.  It weighs four pounds and has a five-year warranty.

Tankless:  One of the best gas sellers in this type is the Rheem RTGH-95 DVLN 95 GPM Indoor Direct Vent Tankless Natural Gas Water Heater.  It measures 18.5 x 9.8 x 27.5 inches, weighs 79 pounds with an energy factor of 0.96, and a warranty of 12 years.

AO Smith Water Heaters

This company offers on most models an up-to-12-year warranty.  They also offer a very extensive selection of water heaters.  For gas water heaters, this company is a better choice.  The company was formed in 1921 and due to the company developing new techniques and methods, they helped to make a revolutionary change in water heaters.

This company is also well-known for manufacturing solar hybrid and tankless high-efficiency water heaters.  Their water heaters have the Energy star certificate for their fantastic performance.

Gas:  This company offers approximately 60 different models of liquid propane and natural gas tank water heaters and is found in about 37% of households.  One gas tank model is the AO Smith GCR-40 ProMax Plus.  It measures 22 x 22 x 58.5 inches and weighs 160 pounds and holds 40 gallons with a six-year warranty.

Electric:  A tankless best seller is the AO Smith EJC-6 Residential Electric Water Heater.  It measures 14.2 x 14.2 x 15.2 with a voltage of 120 and 1600 watts.  It weighs 25.6 pounds and has a six-year warranty.

Tankless:  One of their best gas sellers is the AO Smith ATI-540-H-N Condensing Residential/Light Commercial Tankless Heater.  It measures 12.5 x 18.5 x 29.5 inches, weighs 59 pounds with an energy factor of 0.93, and has a 12-year warranty.

How Long do They Last

It does not matter whether you have a Rheem or AO Smith water heater, most water heaters will last about 10-15 years but it all depends on how you maintain it and use it.  The fiberglass water tank generally will last longer than a standard tank.  Some high-end models will provide a lifetime warranty on the tank so if it goes out, they will replace the water heater.  A damaged tank cannot be repaired, only replaced.

Gas: On average, these types of water heaters will last 9-12 years.  The most common reason they fail is due to faulty corrosion, which happens as they age.  Another reason is that the anode rod starts to corrode and soon fails to attract the corrosive particles.  When these particles reach the bottom of the tank it can eventually cause a leak.

Electric:  Their lifespan is 10-15 years and operates in a similar way to the gas water heaters.  This type of water heater has two heating elements and how durable they will be depends on the maintenance they receive.  Over time, these elements will collect sediment so you have to clean or replace them so they do not cause the water heater to fail.

Tankless:  On average, these water heaters can last at least 20 years but there are some that can last as long as 30 years.  The most common problem with this type is a leakage in the heat exchanger but it is rare for this to happen before it is 15 years old.

Things That Affect the Lifespan of any Water Heater

Improper installation:  If you decide to install the water heater yourself, you need to make sure that it is done properly.  This means that you need to make sure it is wired correctly, it is well-ventilated where you place it so there is no carbon monoxide build-up.  It can also reduce the lifespan of the water heater significantly if it is not ventilated well.

If there is a risk of flooding in your home, make sure that you install the water heater a little above the floor-level.  If the exterior is exposed to water, it could eventually rust the lines, coating, and pipes.

Usage:  As with any appliance, over time they will wear out so the lifespan of your water heater also depends on how often you use it.  If you are constantly using a large amount of hot water, it will push itself to deliver the water you need.  This will cause more wear and tear on your water heater quicker than expected.  With so much hot water being used, it will cause more corrosive effects and deteriorate the system faster.

Infrequent maintenance:  Maintaining your water heater is a significant factor that affects the lifespan of your water heater.  If where you live has hard water, you will need to do more frequent maintenance.  Hard water contains a high amount of minerals, which can reduce the life expectancy of the water heater.  Even soft water can over time cause mineral deposits.

To counteract the mineral and sediment deposits you need to perform timely maintenance.  To reduce the possibility of such build-ups, backflush the unit frequently.  Some of the newer models are equipped with self-flushing technology.

Quality:  The higher the quality water heaters, the better life expectancy. Many times if you purchase a cheaper water heater, you will have to replace it within a few years.  It is true that just because they are more expensive it does not always mean durability and reliability but they will last a lot longer.  There are usually longer warranties on the water heater.

When you are shopping for a new water heater, look for ones that have thick insulation.  The best high-quality water heaters will have a glass-line casing and a very durable heating element.

How Much do They Cost

Rheem water heaters:  The prices for their water heaters range from $650-$1,300.

AO Smith water heaters:  The prices range from $250-$1,500

How Much do They Cost to Have Them Professionally Installed

How much it will cost to have a water heater professionally installed will depend on a variety of things.  On average, for a 40-50 gallon tank, it would cost $400 to $900.    For a tankless water heater, it would be $1,470 to $2,510.  You will also have to pay a plumber for them to install them, which could cost between $250 and $500, which may include taking out the old water heater and dispose of it properly.  For a tankless water heater, it could be from $450 to $1,200.  


The one thing that they have in common is that they both produce quality water heaters for commercial and residential use.  The one big difference is that Rheem products include heating and cooling systems, and air conditioning while AO Smith focuses solely on water heaters.  One thing to note is that Rheem is not known for its customer service but AO Smith is.

When it comes to the preferred choice of plumbers, AO Smith is the one that they would choose.  Their reputation comes from plumbers and homeowners who see their water heaters only needing to be replaced after 30 years or more of service.  

On average per year the water heater energy cost for a gas tank is $350; for a gas tankless is $228. If it is an electric tank water heater it is $463; for an electric tankless it is $190.  With a gas water heater, they need to either have a gas line run to it or installed near a gas line.  It takes approximately 30 minutes to heat 40 gallons of water.

As you can see, both Rheem and AO Smith offer high-quality electric and gas tank and tankless water heaters so which you choose is a matter of preference.