Rheem Vs. AO Smith (Which One Is The Better Water Heater?)

Eli Smith
by Eli Smith
Trying to decide between a Rheem or an AO Smith water heater for your home? Both water heater brands have been around for 100+ years. But that’s not all — let’s see which water heater has the BETTER warranty and higher energy efficiency. And, which brand had more recalls over the years.

In finding the best water heater company, both Rheem and AO Smith are easy contenders for the top. Both of them have a couple of hundred years of experience under their belts. They have also produced an impressive line of products. But when comparing the two, which of these water heater companies is the best?

Based on recall data, Rheem’s water heaters are more reliable than AO Smith’s. In 2016, Rheem recalled 54,000 units due to the control panel overheating, posing a potential fire and burn hazard. However, A.O. Smith had multiple recalls, in 2005, 2008, and 2012. Both water heater brands will last between 6-12 years (if properly maintained). Both offer a minimum of 6 years warranty on the tank and parts.

In this review, we will be looking over the details behind each company. We will be breaking them down into different best of categories based on product as well.

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Rheem vs. AO Smith Comparison (Based on Recall Data)

Recall DateModels RecalledHazardNumber of Units RecalledBrand
October 06, 2005BT-80-271, FCG-75-271, PCG-75-271The water heaters can accumulate soot on the burners, posing a fire hazard.5,000A.O. Smith
January 10, 2008S56A30A54 and S56A30A97The fan’s electric motor is sometimes miswired and overheats, posing a fire hazard.6,300A.O. Smith
April 03, 2008FCG-75 300, FCG-75 301, GS6 75 XRR S, GS6 75 CRR SWater heater’s flute gas temperatures exceed safe limits, posing a fire hazard. Also, exhaust can leak and cause carbon monoxide hazard.1,500A.O. Smith
November 4, 2016XE40M12EC55U0, XE50M12EC55U0, XE50T12EC55U0, XE80T12EC55U0The control panel on the water heaters can overheat, posing fire and burn hazards.54,000Rheem
May 29, 2012FSG and PGX models with serial numbers beginning with MD91, ME91, MF91, or MG91Oversized flue baffles that may produce unacceptably high levels of carbon monoxide29,000A.O. Smith

Which Water Heater Offers Better Energy Efficiency?

As the average family with a household of 3-5 people uses a 50-gallon gas water heater, we decided to compare Rheem’s Performance Power Direct Vent 50 Gallon and AO Smith’s Vertex™ 100 Power Direct Vent 50-Gallon.

Based on our research, we found that AO Smith’s gas water heater is slightly more energy efficient than Rheem’s. The Vertex™ 100 has a UEF (Uniform Energy Factor) of 0.88, while Rheem’s Performance water heater is ranked at 0.80. Both heaters offer a 6-year warranty.

AO Smith’s water heater will allow for unlimited back-to-back showers or as many as 3.5 showers at the same time. It can serve a maximum tub size of up to 112 gallons and has an estimated energy cost of just $155 per month.

Rheem’s comparable water heater offers just 1 back-to-back shower. And, as far as capacity, AO smith’s tank offers 49 gallons while Rheem’s is at 48 gallons.

To review more information about AO Smith’s water heater, Model GDHE-50, head over to their website.

A.O. Smith Water Heater Warranty

AO Smith offers a 6 or 8 year-warranty for residential water heaters, depending on the model number. See this chart below:

Rheem Water Heater Warranty

Rheem’s water heater warranty varies by model, but most models offer a 12-year warranty for the heat exchanger, 5 years for parts, and 1 year for labor.

Some models, like Rheem’s performance Plus heater, offers a 9-year limited warranty for the tank and parts, with a 2-year full in-home labor warranty.

Who Offers The Best Gas Heater?

We are comparing two different water heaters. First, we will be looking at the ProLine XE 50-Gallon Gas Water Heater by AO Smith and the Professional Classic Plus 48 Gallon Natural Gas Water Heater by Rheem.

Our findings have indicated that AO Smith’s ProLine provides better customer experiences.

Below, we will run a comparison telling you why we feel that AO Smith wins this section.

ProLine XE 50-Gallon Gas Water HeaterProfessional Classic Plus 48-Gallon Water Heater
50-gallon tank48-gallon tank
6-year warranty6-year warranty
.72 Uniform Energy Factor (UEF).80 UEF
Energy star qualifiedEnergy star qualified
51x24x24” (HxWxD)60x22x22”

The Unified Energy Factor (UEF) is the Department of Energy’s method of communicating the energy efficiency of a water heater. The higher the number, the higher the energy efficiency.

The UEF varies a bit by size between your different options. Given that these are both the same size, the UEF is the right measurement of what to expect. The UEF on the Professional Classic Plus is a bit higher.

These water heaters are both Energy Star certified, which can potentially lead you to tax breaks in the right state. Not sure which water heater size you need? Check out our guide about Short vs. Tall Water Heaters!

The Proline also boasts of being able to handle more back-to-back showers. Customer experience also seems to match this based on online reviews from around the web.

It is because of that customer experience that we selected AO smith, as these two are pretty handy water heaters in any case.

Who Offers The Best Electric Heater?

This section will have us compare the Professional 50-Gallon Electric Water Heater by Rheem and the Vortex Hybrid Electric Heat Pump by AO Smith. Our choice goes to the Professional Classic Plus by Rheem.

Below is the quick side-by-side.

Voltex Hybrid Electric Heat Pump 50-Gallon Water HeaterProfessional Classic Plus 50-Gallon Electric Water Heater
50-gallon tank50-gallon tank
6-year warranty8-year warranty
3.42 UEF.93 UEF
Energy Star qualifiedNot Energy Star qualified
63x22x22” (HxWxD)62x20x20”

The UEF on the Voltex is much higher. As a result, the Professional Classic Plus is not Energy Star certified based on its online claims. Being a different type of heater, they are subject to other requirements.

The Professional Classic Plus also has a bit more confidence in its product. There is an eight-year limited warranty instead of the Voltex’s six. The overall customer experience between the two is balanced. Still, the edge goes to the Professional Classic Plus Electric Water Heater. Longevity is incredibly vital in water heaters.

Who Offers The Best Electric Tankless Water Heater?

We have chosen the Electric Tankless 24kW by AO Smith and the 24kw Tankless Electric Water Heater by Rheem. Our choice goes to Rheem by a very slight margin.

Here’s the quick side-by-side:

Electric Tankless 24kW 4-Chamber Water Heater R4LA-240E24kw Tankless Electric Water Heater
5-year warranty5-year warranty
Unlimited shower minutesUnlimited shower minutes
5 GPMUp to 6 GPM (gallons per minute)
18x17x6” (HxWxD)18x15x4”

Tankless water heaters are better at single appliances that use continuous water. As a result, they don’t typically work for more than one device at a time, but they do work continuously.

Both of these work similarly. The edge goes to the Tankless Electric Water Heater by Rheem due to a higher GPM. That means it can handle more appliances. On all other fronts, they are incredibly energy efficient and can handle unlimited showers provided you don’t have them connected to one at a time. Find out here if an electric water heater can sit on the floor.

Who Offers The Best Condensing Gas Tankless Water Heater?

As you start looking at gas tankless water heaters, you begin to see some of these numbers crank up. That is because these are for three-bathroom or larger households.

Both the NOx Tankless Water Heater by Rheem and the High-Efficiency Pump by Rheem are great options. But the 15-year warranty is a significant difference-maker here, giving you five additional years of confidence.

Check out the side-by-side comparison below:

Tankless Water Heater Condensing Ultra-Low NOxHigh Efficiency 10.0 GPM Indoor Natural Gas Tankless Water Heater with Recirculation Pump
Energy Star certifiedEnergy Star certified
15-year warranty10-year warranty
.93 UEF.94 UEF
Unlimited back-to-back showersUnlimited back-to-back showers
24x18x11” (HxWxD)29x17x15”

Both of these are incredibly close when it comes to their specifications. Also, they are both accredited by Energy Star. Their impressive UEF ratings indicate this. The real difference-maker here comes back to that 15-year warranty, but both are incredible options for your household.

Rheem vs. AO Smith: Who Offers More Warranty?

AO Smith offers a longer and more flexible warranty. While AO smith offers between 6-10 years on their water heaters and an extended warranty on other products, Rheem’s warranty is very limited at 5 years for parts.

AO Smith offers an 8-year warranty for residential water heaters with the following models: HUC-40, HUR-40, HUC-50, HUR-50, HURT-50L 50k btu, and HURL-40 short. They also offer a 6-year warranty for water heaters with models GUC-30, GUC-40, GUR-40, GUC-50, GURT-50 50K btu, and GURL-40 short.

Rheem offers a 12-year warranty from the effective date for the heat exchanger, 5 years for the parts, and 1 year for labor.

So, Is Rheem Better Than A.O. Smith?

Rheem has a fantastic selection of water heaters that cover a wide variety of residential and homeowner needs. But more importantly, their units are recalled less often than A.O. smith, who had multiple recalls over the years due to fire hazards.

Because of this, we have selected them to be the best brand by a slight edge. They focus on what water heaters need to be helpful: efficient and simple water heaters. Rheem also tends to have a more substantial customer backing. However, based on our research and user feedback, we find that the two are pretty close in reliability.

That customer base is a strong indicator of consistent quality. But don’t count out AO Smith as a distant second place. They are pretty close to Rheem in many ways.

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Eli Smith
Eli Smith

I'm a guy who becomes the expert of whatever I stumble upon, writing-wise. I've written tons about cool home products, home improvement, and smart technology in the home. I'm also the proud father of a kiddo born on new years, making my holidays very busy.

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