The premium electric tankless comparison. Stiebel Eltron Tempra Plus is widely regarded as the best whole-house electric tankless on the US market — and Westinghouse WET competes as the mid-tier value alternative.
Side-by-side (volume sizing)
| Westinghouse WET-27 | Stiebel Tempra 24 Plus | Stiebel Tempra 29 Plus | |
|---|---|---|---|
| kW | 27 | 24 | 28.8 |
| Modulation | Constant power | Flow Control | Flow Control |
| Element | Stainless | Solid copper | Solid copper |
| Heat exchanger warranty | 10 years | 7 years | 7 years |
| Parts warranty | 5 years | 3 years | 3 years |
| Cold-climate performance | Good (output drops at peak flow) | Excellent (Flow Control maintains temp) | Excellent |
| Origin | USA | Germany | Germany |
| Typical price | $649-799 | $799-999 | $849-1,049 |
The Flow Control difference
This is the most important practical difference between the brands. Stiebel Tempra Plus uses Flow Control — when demand exceeds capacity, the unit throttles flow to maintain output temperature. Westinghouse WET uses constant-power modulation — when demand exceeds capacity, output temperature drops.
With 40°F incoming water and 3 GPM demand:
- Westinghouse WET-27: outputs ~111°F (warm but not hot)
- Stiebel Tempra 24 Plus: reduces flow to ~2.5 GPM, outputs at 120°F (full hot)
For Sun Belt warm-water installs where peak capacity is plentiful, Westinghouse is fine. For cold climates, Stiebel\'s Flow Control matters dramatically.
Warranty comparison
- Westinghouse 10-year heat exchanger / 5-year parts
- Stiebel 7-year heat exchanger / 3-year parts
On paper, Westinghouse warranty is longer. Field-reliability reputation favors Stiebel — but Stiebel\'s premium pricing reflects that.
Where Westinghouse leads
- Lower price — typically $150-250 less than equivalent Stiebel Tempra
- Longer heat exchanger warranty on paper (10-yr vs 7-yr)
- Longer parts warranty (5-yr vs 3-yr)
- US manufacturing (US Craftmaster) for buyers preferring domestic
- Adequate for warm-climate installs
Where Stiebel leads
- Flow Control technology — meaningful cold-climate advantage
- German engineering quality — visible in build and field reliability
- Solid copper elements — more durable in hard water than stainless
- Direct factory tech support — engineers available for diagnosis
- Established reputation in cold-climate electric tankless
Which to choose
- Sun Belt, small home, budget priority: Westinghouse WET-18 or WET-27
- Moderate climate, value priority: Westinghouse WET-27
- Cold climate, performance priority: Stiebel Tempra Plus (Flow Control)
- Large home, simultaneous demand: Stiebel Tempra Plus (Flow Control handles capacity excess gracefully)
- Hard water, long ownership: Stiebel (solid copper elements)
Bottom line
Westinghouse WET is the value tier with longer warranty terms. Stiebel Tempra Plus is the premium tier with materially better cold-climate technology. Climate is the deciding factor — warm climates make Westinghouse competitive; cold climates justify Stiebel\'s premium.