A.O. Smith Water Heaters: Models, Performance, and Are They Worth It?

A.O. Smith is one of the three dominant manufacturers in the US residential water heater market — alongside Rheem and Bradford White. They sell through both retail (Lowe's carries A.O. Smith) and wholesale contractor channels, and they manufacture several other brand names you may recognize. Here is a complete look at the A.O. Smith residential lineup.

The A.O. Smith Brand Family

A.O. Smith is larger than their brand name suggests. Through acquisitions, they also manufacture water heaters sold under the American Water Heaters, State Industries, Reliance, and Whirlpool brand names. If you have one of these brands in your home, it was made in the same facilities as A.O. Smith units, often with nearly identical components. This means parts availability and service support are effectively shared across these brands.

Residential Product Line

Signature Select — The Mid-Tier Workhorse

The Signature Select is A.O. Smith's most widely installed residential series and is the unit most professional plumbers source through wholesale distribution. Available in 40, 50, 65, and 75-gallon gas configurations with BTU inputs from 36,000 to 50,000, and in 40 and 50-gallon electric configurations. The 8–10 year warranty puts it in the same tier as Rheem's Performance Plus and Bradford White's standard residential line.

The Signature Select's Blue Diamond glass-lined tank is A.O. Smith's proprietary lining technology — they claim it's harder and more resistant to corrosion than standard glass lining. Independent verification of this claim is limited, but A.O. Smith tanks have a solid industry reputation for longevity when properly maintained.

Voltex Hybrid Heat Pump Water Heater

The Voltex is A.O. Smith's heat pump offering and competes directly with the Rheem ProTerra. Key specs: 50 or 80-gallon capacity, efficiency factor of up to 3.45 COP, 10-year tank warranty, and ENERGY STAR certification (which qualifies it for the federal 30% tax credit).

Compared to the Rheem ProTerra (COP 3.75), the Voltex's efficiency rating is somewhat lower, though real-world performance differences in most installations are modest. Both are excellent heat pump units. The Voltex is a strong choice if your contractor sources A.O. Smith through their distributor or if you find better pricing on the Voltex in your market.

A.O. Smith Condensing Tankless

A.O. Smith's tankless lineup competes in the same segment as the Navien NPE series. Their Condensing Plus series features UEF ratings up to 0.95, a stainless steel heat exchanger with a 15-year warranty, and flow rates up to 11 GPM. Performance is comparable to Navien, though Navien has a longer track record in the North American condensing tankless market and somewhat stronger contractor training support.

Where A.O. Smith Excels

A.O. Smith's strongest differentiators are the breadth of their product line, strong nationwide parts availability (given the scale of their manufacturing operation), and the Blue Diamond lining that performs particularly well in moderately hard water. Their warranty terms are competitive with Rheem at every tier.

Honest Limitations

A.O. Smith's retail distribution through Lowe's means their entry-tier Signature units are more commonly installed by homeowners doing DIY work — which doesn't reflect negatively on the units themselves, but does mean you encounter more improperly installed A.O. Smith units in service than Bradford White (which is contractor-only). When professionally installed, A.O. Smith units perform at the same level as competing brands in the same tier.

Bottom Line

A.O. Smith is a high-quality manufacturer with a full product line from entry-level to premium. For most homeowners the choice between A.O. Smith, Rheem, and Bradford White comes down to what your installer sources and prefers — all three brands make reliable units when properly installed. The unit brand matters less than the installation quality and the warranty terms for your specific unit.