Stiebel Eltron and Rheem compete directly in two segments: whole-house electric tankless (Tempra Plus vs RTEX) and residential heat pump water heaters (Accelera vs ProTerra). Different positioning — German premium vs US mainstream.
Whole-house electric tankless
| Stiebel Tempra 29 Plus | Rheem RTEX-29 | |
|---|---|---|
| kW | 28.8 | 28.8 |
| Modulation | Flow Control (regulates flow) | Constant power |
| Cold-climate performance | Excellent — Flow Control maintains temp | Good — output temp drops at high flow |
| Element | Solid copper | Stainless |
| Heat exchanger warranty | 7 years | 5 years |
| Parts warranty | 3 years | 1 year |
| Typical price | $849-1,049 | $549-699 |
Heat pump water heater
| Stiebel Accelera 300 E | Rheem ProTerra 80 | |
|---|---|---|
| Capacity | 80 gal | 80 gal |
| UEF | 4.5 | 4.0 |
| Tank warranty | 10 years | 10 years |
| Breaker | 15A | 30A |
| Smart connectivity | Limited | EcoNet Wi-Fi (mature) |
| IRA tax credit eligible | Yes | Yes |
| Typical price | $2,499-2,999 | $2,099-2,499 |
Where Stiebel wins
- Tempra Plus Flow Control — major cold-climate advantage over RTEX constant-power
- Accelera 4.5 UEF — 10-15% more efficient than ProTerra
- German build quality
- Direct factory tech support — phone diagnosis from engineers
- Longer Tempra Plus warranty (7-yr heat exchanger vs 5-yr RTEX)
Where Rheem wins
- Lower price on both electric tankless and heat pump
- EcoNet Wi-Fi — mature smart-control ecosystem
- Home Depot install service available nationwide
- Wider US contractor base familiar with Rheem
- Broader product line covering gas tankless, traditional tanks, commercial
Which to choose
- Cold climate + want best electric tankless: Tempra Plus
- Warm climate + budget: RTEX
- Maximum heat pump efficiency: Accelera
- Heat pump + smart-control integration: Rheem ProTerra
- Need install through Home Depot: Rheem
- Want lifetime warranty on heat exchanger: neither — EcoSmart for that
Bottom line
Stiebel wins on technology (Flow Control, 4.5 UEF) and build quality. Rheem wins on price, smart-control maturity, and US contractor availability. For premium cold-climate or maximum-efficiency installs, Stiebel justifies the premium. For value installs, Rheem is the practical choice.