Buying the right water heater for your home, office or commercial space is always a hard nut to crack. But as it seems, you’ve made your choices extremely confined between two brands- Rheem and AO Smith. 

From a bird’s eye view, Rheem masters in building heavily performing electric water heaters, where AO Smith specializes in gas-powered ones. In terms of accessories, Rheem is richer. But AO Smith sports better energy efficiency. And the comparison can go on and on.

But if we generalize the comparison from an end user’s point of view, having a straight verdict is pretty hard. In the 11th hour of making a decision, this hectic comparison can drive you nuts. 

This is what drove us to craft this entire piece. Take some minutes to go through the whole comparison of Rheem vs AO Smith and we’ll come to a decision eventually. 

AO Smith or Rheem- Which Is For Whom?

Before we dive into the depth of today’s comparison, let’s put our short summary upfront. 

So, what kind of users should go with which brand. See yourself within which brand you’ll be loving to fall in- 

Buy Rheem Products If- 

  • You need heavily performing electric water heater(tank/tankless)
  • You need condensing tankless heaters(electric) only. 
  • A number of home enhancement products apart from heaters. 
  • Wide range of accessories and replacement parts. 

Buy AO Smith Products If- 

  • You need top-notch gas-powered water heaters. 
  • You’d love to find the right match from a wide heater diversity. 
  • You need better energy efficiency. 
  • You’re dependent on professionals for service or repair. 

Got into the shoe? Here goes the broken down reasoning behind the claim- 

Rheem or AO Smith: Head to Head

Rheem AO Smith
Operating for    85+ years 99+ years
Product Category            Residential and Industrial    Residential and Industrial
Core Products          Water heaters, Furnace, AC, Coil    Water heaters, Boilers and Tanks
Power Options    Gas and Electric    Gas and Electric
Number of Models(WH)              58 (tanked)  37 (tankless) 268 (tanked)  51 (tankless)
Warranty          6 years to lifetime    6 – 10 years  
Geo-based Service & Repair    Yes(up to 25 miles)      Yes(up to 100 miles)
Best for          Electric Heaters  Yes(up to 100 miles)


In-Depth Comparison Between Rheem vs AO Smith

Product Diversity

By far, almost all of us know that both of our brands of the day are into a water heater manufacturing regime. But none of them are limited within ‘Just’ water heaters anyway. In terms of the exact product lineup, they share some common space and some unique ones as well. 

Product Lineup of Rheem

ao smith vs rheem

For years, Rheem had been into water heaters of various forms into the categories of both commercial and residential kinds. 

Under residential wing, they’ve got a rich lineup containing water heaters, water heater boosters, smart thermostats, tankless water heaters, combi water boiler, mini-splits as their innovative and signature product. Also, they provide a number of heating and cooling solutions, pool and spa heating, home enhancement amenities, etc. 

Moving forward to the commercial segment, the brand also features a number of featured innovations in product form as they do for residents. Among the signature products, they have commercial tankless heaters, rooftop water heaters, commercial HVAC lines, etc. They also have packaged heat pumps, ACs, split ACs, commercial air handlers, and so on. On top of that, commercial solutions in forms of gas water heater, electric water heater, storage tanks, etc. are also in their bag to offer. 


Product Lineup of AO Smith

rheem vs ao smith water heater

As they claim to be one of the leading manufacturers of residential and industrial water heater industry, the product lineup will talk quite on its behalf. Just like the previous brand, they also have two separate wings of residential and commercial products. 

Here goes the listing in-depth- 

For residential purposes, the frontline products are gar tank water heaters, electric tank water heaters, heat pump heaters for water, tankless(both electric and non-electric) water heaters, and finally- combi boilers. With all of them, they also manufacture accessories and individual tanks as well. 

On the flip side, they have commercial water heaters, boilers, packaged HVAC systems, storage tanks, and accessories for industries and offices. 


Comparison Table: AO Smith Vs Rheem Water Heater Diversity

Factor to Compare

Rheem                                AO Smith
Residential Tank Water Heater        Yes(Gas and electric both)    Yes(Gas and electric both)
Tankless Water Heater  Yes(Condensing and electric both)  Yes(Gas and electric both)
Residential Combi Boilers          Yes Yes
Residential Tank & Accessories  Yes(Accessories only)    Yes
Residential Pool and Spa Heaters  Yes No
Hybrid Water Heaters    Yes No
Residential Solar Water Heater        Yes No
Commercial Tank Water Heater     Yes(Gas and electric both)  Yes(Gas and electric both)
Tankless Water Heater    Yes(Gas and electric both)   Yes(Condensing or Non-Condensing)
Commercial Boiler    Yes Yes
Package System    Yes(AC, Heat Pump)    Yes
Commercial Storage Tanks    Yes Yes
Heater Accessories      No Yes
Winner Rheem


Product Quality: Tanked and Tankless Heaters

The next factor to compare and be concerned about is the Rheem vs AO Smith water heater quality of tanked and tankless types. 

Tanked heaters are one of the most familiar forms of water heaters for both residential and commercial aspects. They are cheaper in price and installation, and easier to operate and troubleshoot as well. 

On the other hand, it’s a world of minimalism, which has touched the water heater of your home. For more continuous, hassle-free, and instant water heating facilities, people are moving more towards tankless heaters, and so do brands like Rheem and AO Smith.

So, what are we going to compare between tanked/tankless heaters of Rheem and AO Smith? To make things simpler, we’ve divided that into a few sub-factors- 

Sub-factor 1: Number of Heater Model

When it narrows down to the number of choices you have within tanked/tankless heater models, this is what two of our brands have to offer- 

Rheem: With quite some differentiating factors, Rheem produces 15 tanked water heaters of electric type, and 43 tanked water heaters of gas-type. They vary a lot regarding the BTU capacity, water capacity, emission rating, pipe system, etc. 

On the other hand, Rheem has three kinds of tankless heaters for residents- 

  1. Mid-Efficiency Tankless Water Heaters: 12 Models
  2. High-Efficiency Tankless Water Heaters: 12 Models
  3. Tankless Electric Water Heaters: 13 Models

AO Smith: AO Smith is the proud manufacturer of over 270 models of tanked water heaters. 66 of them are electric tanked water heaters, where 206 of them are of gas-driven models. In terms of gallons of water capacity, dimension, fuel type(propane/natural gas), pump technology, wattage, voltage, and other handy features, you can pinpoint the exact model you need. 

Moving to the other hand, the brand has a rich lineup containing 51 tankless water heaters in total. 18 of them are electric, and 33 of them are gas-powered. 

Sub-factor 2: Energy Efficiency 

As an end-user, energy consumption and its efficiency top the priority list. Hence, here are the insights from both of the brand’s tanked heaters- 

Rheem: Instead of the typical energy efficiency rating, Rheem had been smart enough to introduce the new Uniform Energy Factor(UEF) as the rating measure of their tanked hater’s energy efficiency. 

Within a certain scaling, here is the list of some of Rheem’s most energy-efficient tanked heater models/series- 

  • Professional Prestige Series: 0.80 – 0.83 UEF
  • Performance Power Direct Vent 50 Gallon Gas Water Heater: 0.80 UEF
  • Performance High-Efficiency Condensing Power Direct Vent: 0.81 UEF

We can put the tankless models from Rheem into the same scare of energy efficiency as well. 

Look at some highly energy-efficient tankless heaters from Rheem- 

  • Tankless Mid-Efficiency 95 Direct Vent Indoor: .82 UEF -US
  • Mid-Efficiency 84 Direct Vent Indoor: .82 UEF -US
  • Tankless Mid-Efficiency 84 Outdoor: .82 UEF -US

AO Smith: AO Smith had taken both of the convenient and newest paths when it comes to rating their tank or tankless heaters. They have got the UEF ratings and have got the well-known ‘Energy Star’ ratings as well. And this works equally for both gas-driven and electric tanked/tankless heaters from the brand. 

In terms of top UEF rating, here are some of the tanked heaters from the brand- 

Gas-type AO Smith Tanked Heaters with Top UEF Rating 

  • Polaris® High-Efficiency GSP 100 (LP): 0.90 UEF
  • Vertex™ 100 Power Direct Vent Propane Water Heater: 0.86 UEF
  • ProLine® XE SL Power Vent 50-Gallon Gas Water Heater: 0.73 UEF

Gas-type AO Smith Tankless Heaters with Top UEF Rating-

  • Tankless Water Heater ATI-240H-N, 160,000 BTU: 0.94 UEF
  • Tankless Water Heater ATI-540H-N, 199,000 BTU: 0.95 UEF

Electric AO Smith Tanked Heaters with Top UEF Rating- 

  • Voltex® Hybrid Electric Heat Pump 66-Gallon Water Heater: 3.35 UEF
  • Hybrid Electric Heat Pump 50-Gallon Water Heater: 3.45 UEF
  • Voltex® Hybrid Electric Heat Pump FPTU-50: 3.42 UEF

Electric AO Smith Tankless Heaters with Top UEF Rating-

  • Tankless R4MA-320E 4-Chamber Water Heater: 0.93 UEF
  • Electric Tankless R4LA-240E 4-Chamber Water Heater: 0.92 UEF 

Lastly, here are some of their products with Energy Star approval- 

  • Voltex® Hybrid Electric Heat Pump HPTU-80N
  • Hybrid Electric Heat Pump FPTU-80
  • Voltex® Hybrid Electric Heat Pump HPTU-66N

Comparison Table: Rheem vs AO Smith Product Quality

Factor to Compare

Rheem                      AO Smith
Number of Tanked Heater Model    15 (Electric) 43 (gas-type)   66 (Electric) 206 (gas-type)
Energy Efficiency Scale             UEF(Uniform Energy Factor)    UEF and Energy Star
Best UEF Range 0.80 – 0.83 UEF  3.45 UEF
Winner AO Smith


Design and Installation 

As long as it’s a complicated HVAC device, we hardly bother installing and replacing it ourselves. Instead, we prefer calling the professional on the rescue. 

But still, if you have a bit of DIY-ship in you and you care about what you pay for, you should know about the design and installation process of heaters of both brands. 

Here you go- 

Rheem Design And Installation:

a.o. smith vs rheem water heaters

As long as it’s design and innovation, Rheem never stops to keep pushing themselves to break boundaries. As a consequence, we’ve got to see a number of signature products from their inventory. 

Products like Gladiator Water Heater, Smart Thermostats, and Condensing Tankless Heaters are the toppers of the list of their innovative products. 

About installation, the brand has got a service called ‘Find A Pro’ that connects you and any independent Rheem serviceman within 25 miles. But these third party contractors are not directly authorized by Rheem. So in case of any inconvenience, you have to take the liability and bear the damage cost. 


AO Smith Design And Installation:

ao smith vs rheem water heaters

About the design of AO Smith heaters and accessories, the greatest selling point is the diverse range of product design in terms of size, capacity, energy efficiency, water tank size, fuel type, and so on. 

So, what they’d offer you is to pinpoint your necessity and they will find the closest match from their rich inventory right away. The AO Smith water heater reviews that we’ve gone through are also supporting the fact. 

About the installing department, AO Smith sports a similar search feature within a certain radius (10, 15, 20, 25, and even 100 miles) that would get you a trained serviceman. Unlike Rheem, the good part about this service is, AO Smith took the liability to train these contractors up. 


Comparison Table: Rheem vs AO Smith Design and Installation

Factor to Compare

Rheem              AO Smith
Design Quality  Excellent Satisfactory
Design Diversity    Good  Excellent 
Geo-based Service Finder Yes(up to 25 miles)  Yes(up to 100 miles)
Customer Support      Good Excellent
Winner AO Smith



Heaters are troublesome, no matter how good a brand’s products are. Therefore, the warranty policy of the manufacturers and their tendency to stick to them is definitely important. 

Have a look at what our brands of the day are saying about their warranty and stuff.


ao smith vs rheem gas water heater

Once you get to register your Rheem product through their website, you’ll get access to Rheem support and warranty services, including extended warranty (optional). The registration process might look hefty for the first time, though. 

Once you register and verify your warranty rights, you’ll be under their limited warranty policy that starts from 6 years. The upper limit of the extended warranty is up to the time when the owner leaves the house where the product was installed. Some of the verified Rheem water heater reviews say that it might take longer to reach you if you’re in a remote location. 


AO Smith: 

rheem water heater vs ao smith

AO Smith has a similar process of verifying the warranty rights of the user. Once you opt-in there and put your serial and reference number, you’ll be eligible for their 6-10 years warranty policy. Winner: Rheem


Parting Words

Having said that all, we’d advise you to pay deep attention to whatever you’re paying for. Also, beware of the faults and loopholes in the customer service, repair, and warranty policy. This will prevent any unexpected costs to take place with your heaters. 

Good luck!