Tempra Plus is Stiebel Eltron\'s flagship — and widely regarded as the best whole-house electric tankless water heater on the US market. Six sizes from 14.4 kW to 36 kW, all with Flow Control modulation that maintains setpoint temperature by throttling flow rather than letting output temperature sag.
The lineup
- Tempra 12 Plus — 14.4 kW. Warm-climate, small homes
- Tempra 15 Plus — 14.4 kW. Same kW as 12; slight efficiency tuning
- Tempra 20 Plus — 19.2 kW. Moderate climates, 1-2 bathrooms
- Tempra 24 Plus — 24 kW. Moderate-to-cold climates, 2 bathrooms
- Tempra 29 Plus — 28.8 kW. Cold-climate volume pick, 2-3 bathrooms
- Tempra 36 Plus — 36 kW. Largest, cold-climate 3+ bathroom homes
Key features
- Flow Control technology — auto-modulates water flow to maintain setpoint temperature. The single biggest Tempra Plus differentiator. See Flow Control explained
- Solid copper heating elements — premium element design vs stainless competitors
- Digital control panel with setpoint adjustment and error display
- Modulating power — units adjust kW output to demand
- Compact wall-mount — typically 17"×14"×4" deep
- Whisper-quiet operation — no fan, no flame, no combustion noise
Specs
| Model | kW | Breakers | GPM at 70°F rise | GPM at 50°F rise |
|---|---|---|---|---|
| Tempra 12 Plus | 14.4 | 2× 60A 240V | 1.7 | 2.6 |
| Tempra 15 Plus | 14.4 | 2× 60A 240V | 1.7 | 2.6 |
| Tempra 20 Plus | 19.2 | 2× 80A 240V | 2.3 | 3.5 |
| Tempra 24 Plus | 24.0 | 2× 60A + 1× 40A 240V | 2.8 | 4.3 |
| Tempra 29 Plus | 28.8 | 3× 50A 240V | 3.4 | 5.2 |
| Tempra 36 Plus | 36.0 | 3× 60A 240V | 4.2 | 6.5 |
Sizing for your climate
See complete sizing guide. Quick rules:
- Sun Belt: Tempra 15 or 20
- Mid-Atlantic: Tempra 24 or 29
- Upper Midwest / cold climate: Tempra 29 or 36
- Far north winter: Tempra 36 (verify service panel can support)
Service panel considerations
Whole-house electric tankless requires major electrical service. Tempra 36 Plus draws 150A continuous. Many 200A residential services don\'t have spare capacity for whole-house electric tankless without service upgrade or load-shed switch.
Stiebel\'s Smart Energy Logic load-shed switch allows Tempra to share service capacity with a single major load (electric range, EV charger) by temporarily disconnecting the other load during a hot water call. Limited application but can avoid $2,500-5,000 service upgrade in some installs.
Warranty
- 7-year heat exchanger
- 3-year parts
- Labor not covered
Bottom line
Tempra Plus is the premier whole-house electric tankless. Flow Control transforms cold-climate electric tankless from "barely usable" to "reliable." Choose Tempra 29 Plus as the volume cold-climate pick, Tempra 36 Plus for largest homes, Tempra 12-15 Plus for warm-climate compact installs. Verify your electrical service before purchasing.