AO Smith Water Heaters
Review & Buying Tips
(updated 2018)

AO Smith water heaters review helps you find the best models to buy from one of the biggest US manufacturers of HVAC equipment. Search, review and select a model from ProLine, Effex, Voltex, Polaris, Voltex, and Vertex, powered by electricity, natural or propane gas, and built with the water tank or tankless.

The list of AO Smith hot water heaters for residential applications is very long, so homeowners have more flexibility and options to choose from; from the economy gas and electric models to the advanced models with superior features and quality, some equally good as found in the commercial line.

This is what you will find in our review on AO Smith water heaters:

Top features
Gas models
Electric models
About the company

Advanced features

AO Smith manufacturer, as a leader in innovation and manufacturing energy-saving models, designs, builds, distributes and field supports an entire line of residential and commercial water heaters and boilers, offering many great features:

  • Blue Diamond, commercial-grade glass coating - provides superior corrosion protection and longer tank life, due to the high-quality material and advanced technology.
  • CoreGard anode rod - made of stainless steel that protects the internal metal surface of water tank heaters from corrosion. Standard models utilize one, while better models have two rods, or powered one, resulting in longer warranties.
  • DynaClean is the automatic sediment cleaning system that utilizes durable dip tubes, so there is less sediment build-up accumulated from the hard water.
  • Self-powered electronic gas valve - utilize a microprocessor, thermopile and LED status indicator, so water heater works with enhanced performance, independent of the external power source, easily controlled and troubleshoot.
  • Green Choice is the eco-friendly burner designed to reduce greenhouse gases up to 33%.
  • AO Smith water heaters meet a standard, "Flammable Vapor Ignition Resistant" that deals with the accidental ignition of flammable vapor outside of the water heater. For the ignition problems on AO Smith Vertex models, and how to troubleshoot, check out this step-by-step guide.
  • Durable brass drain valve, heat trap nipples and hot-surface ignitor for higher energy efficiency and reduced energy consumption.

Review of AO Smith water heaters

There are two main types of AO Smith water heaters for home use; tank-type with the capacities of up to 98 gallons and tankless for single or multiple fixtures use, both powered either by gas or electricity. All the models are grouped into three categories where the ProLine XE is, according to the manufacturer, the best to buy.

Best gas models to buy

Tank type

Residential gas water heaters from AO Smith come in much greater number than the electric, where the variety of models are available. Based on the venting options, gas models are found as the atmospheric, power vent, direct vent, and power direct vent.

Gas models are coming from the ProLine series, and are recommended to every homeowner, either looking for the economy models, models with the reduced gas emission, condensing with the ultra high efficiency or high recovery - for larger families.

AO Smith water heaters are also designed with the latest technology, state-of-the-art design, and long-lasting elements. 

Vertex and Polaris, with the helical heat exchanger, condensing design, advanced gas and electronic control, heavy duty anodes and stainless steel tank, are two of the most innovative and efficient tank-type models from AO Smith - definitely recommended to those who are looking for more. 

When it comes to savings, Vertex Power-Direct Vent model, as the high performing and Energy Star unit that also provides an endless supply of hot water, has the annual cost of operation around $200 (year - 2017).

More affordable while still coming from the best ProLine XE series is the power-direct vent model GPDX 50L. This 50-gal model has the highest First Hour Rating (118 gallons) and energy factor (0.73) of all non-condensing models with the 50-gal tank capacity. Or if you need a water heater that produces more hot water, buy GPDX 75L.

Tankless series

AO Smith water heaters are also designed with the tankless technology, which means water is heated on demand and distributed in endless supply, either for point-of-use or whole-house use. ProLine XE tankless are available as the condensing or non-condensing, where the high efficient models, with the recirculation pump and low gas emission, are the most advanced. AO Smith tankless heaters are smart, safe and small and can be installed either inside or outside (depends on the model).

A good example is the model ATO-540H-N, one of the top sellers and with the most positive user reviews. It comes with the commercial grade components and high energy factor and water flow making it ideal for homes with up to 4 baths.
This is a good buy.

Residential electric models

Most of the AO Smith water heaters that use electricity are coming from the ProLine series, built for residential and mobile homes, as the standard or advanced models. One of the top water heaters is coming from the ProLine XE series, featuring the electronic display, a diagnostic system, stainless steel heating elements, dry fire protection, multiple operating modes and
10-year warranty. This is what ensures maximum energy savings, excellent power output,  faster recovery, and reliable operation.

Electric models can be found for special use also, as the Lowboy, Table Top or point-of-use for under sink installations and single use.

Hybrid models

With an addition of the heat pump, AO Smith electric water heaters can now operate with ultra-high efficiency, two times more efficient than the conventional type.

This is what makes Voltex heat pumps Energy Star compliant that can save over 50%. These are also known as hybrids - the most advanced electric units that utilize the heat pump and long lasting heating elements with dry fire protection, electronic control panel for programming and troubleshooting. With several models available, Voltex, heat pumps from AO Smith, do a great job in supplying plenty of hot water - up to 5 showers operating at the same time.

Most of the tank-type water heaters from AO Smith come with the warranty of 6 years, either budget-friendly models or advanced such as Vertex, while some, such as Polaris or Voltex have a 10-year warranty.

Tankless have a longer warranty from all of the tank-type gas and electric models - 15 years.

About AO Smith

AO Smith company is a leader in water heating industry that is in HVAC business for over 70 years. The company is well known for the quality and innovation in energy efficiency and tank protection, such as the glass lining, AO Smith's patented process, that is now a standard in the water heating industry.

AO Smith is the owner of several popular brands that are present on the market today: State, Reliance, Maytag, American, GSW, and John Wood.

How to contact AO Smith
Official website:

Related articles

ProLine gas series review
Vertex review
Effex gas
Infinity tankless series review
ProLine electric
Voltex heat pump review
Power vent models
Direct vent models
30-gal gas comparison
40-gal gas comparison
50-gal gas comparison

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