Rheem and AO Smith are the two dominant US residential water heater brands — combined, they hold ~70% of the market. They're also direct competitors at every tier: tank gas, tank electric, heat pump, tankless. Picking between them comes down to which retailer channel you're buying through, what warranty terms you value, and (sometimes) which brand your installer prefers. This page is the head-to-head.
The tier-by-tier matchup
| Tier | Rheem | AO Smith | Edge |
|---|---|---|---|
| Premium gas tank 50G | Performance Platinum (12-year) | Signature Premier (9-year) | Rheem on warranty length |
| Mid gas tank 50G | Performance Plus (9-year) | Signature (9-year) | Tie — pick by retailer |
| Entry gas tank 50G | Performance (6-year) | Signature 100 (6-year) | Tie |
| Heat pump 50G | ProTerra (10-year) | Voltex (10-year) | Tie — equivalent |
| Heat pump 80G | ProTerra 80G | Voltex 80G | Tie |
| Premium gas tankless | RTGH-95DVLN (9.5 GPM, 12-year HX) | ProLine Tankless 10 GPM (15-year HX) | AO Smith on warranty + flow |
| Lifetime tank | Marathon (limited lifetime) | No equivalent | Rheem — unique |
| WiFi platform | EcoNet (mature) | iCOMM (newer, fewer features) | Rheem on smart-home |
Warranty depth
Rheem ships longer warranties at the premium tier:
- Premium 50G gas: Rheem Performance Platinum 12-year vs AO Smith Signature Premier 9-year — Rheem wins by 3 years
- Lifetime tank: Rheem Marathon limited-lifetime — AO Smith has no equivalent
- Heat pump: both 10-year — tie
- Tankless: AO Smith ProLine 15-year HX vs Rheem RTGH 12-year — AO Smith wins by 3 years
For warranty math, Rheem wins on tank-tier; AO Smith wins on tankless heat exchanger.
Real-world reliability
Industry reliability data shows the two brands roughly equivalent. Specific failure-mode patterns:
- Rheem entry-tier gas valves fail more commonly at year 7–9 than the AO Smith equivalent
- AO Smith Coregard anode rod depletes slower than Rheem's aluminum-zinc — meaningful 2–3 years of extra tank life if no anode replacement happens
- Rheem ProTerra compressor has slightly higher early-life failure rate than AO Smith Voltex (Rheem has improved this; verify warranty covers the compressor specifically)
- AO Smith Hydrojet sediment-reduction feature is a real maintenance benefit that Rheem doesn't match
Net: equivalent for most buyers. Edge cases depend on the specific failure modes you're concerned about.
Smart-home / WiFi
Rheem EcoNet is the more mature platform — it ships on Performance Platinum, ProTerra, and Prestige tankless tiers, has well-developed app features (leak alerts, scheduling, remote temperature, vacation mode), and integrates with major smart-home platforms.
AO Smith iCOMM is newer and shipped on fewer SKUs. The feature set is comparable but the integrations with other smart-home platforms are less mature.
For smart-home priority buyers: Rheem.
Retailer channel
- Home Depot: primarily Rheem — see our Home Depot Rheem hub
- Lowe's: primarily AO Smith — Rheem stocking is narrower
- Rheem Pro Partner network: contractor-channel Rheem distribution
- AO Smith dealer network: contractor-channel AO Smith distribution
For DIY shoppers, your retailer often dictates the brand. For pro-installed jobs, your installer's preferred brand often dictates.
Pricing
At equivalent tier and capacity, pricing is within $50–$100 between the two brands. Neither has a sustained price advantage. Promotional pricing varies seasonally — check both at the moment of purchase.
Specific product matchups
Rheem Performance Platinum 50G Gas vs AO Smith Signature Premier 50G Gas
Rheem wins on warranty (12 vs 9 years) and EcoNet WiFi standard. AO Smith wins on Coregard anode (longer-lasting) and Hydrojet sediment reduction. Price within $100. Pick Rheem for smart-home priority + max warranty; AO Smith for build-quality emphasis.
Rheem ProTerra 50G vs AO Smith Voltex 50G
Spec-equivalent. Same UEF (~3.45), same 10-year warranty, same 65 GPH FHD. Rheem ships EcoNet, AO Smith ships iCOMM — Rheem's app is more mature. Pricing within $50. Pick Rheem if EcoNet matters; tie otherwise.
Rheem RTGH-95DVLN vs AO Smith ProLine Tankless 10 GPM
AO Smith wins on flow (10 vs 9.5 GPM) and warranty (15 vs 12 years). Rheem wins on EcoNet integration (standard vs separate module on AO Smith). Pick AO Smith for raw spec/warranty; Rheem if smart-home is the priority.
Bottom line
For most buyers, the choice between Rheem and AO Smith comes down to retailer availability and installer preference. Rheem wins on warranty length at the premium tank tier, has the only lifetime-tank option (Marathon), and has a more mature smart-home platform. AO Smith wins on tankless warranty and the Coregard anode. Both are competitive across the lineup.
For broader Rheem context see our Rheem lineup. For the alternative comparison see Rheem vs Bradford White.