PRODUCT REVIEW
In-Depth U.S. Market Review
The Stiebel Eltron Tempra 29 Plus Tankless Water Heater represents the high-end, premium choice in the U.S. electric tankless market. German-engineered and manufactured, this unit is designed to meet the rigorous demands of cold-climate, whole-house hot water delivery. Its 28.8kW power rating (often simply referred to as 29kW) places it among the most powerful electric models available, making it the definitive choice for larger U.S. homes, especially those in the Northern states and high-demand areas.
This unit's niche is the homeowner who prioritizes superior performance, reliability, and precision over initial cost and installation simplicity. The Tempra 29 Plus is famous for its Advanced Flow Control feature, which automatically maintains a constant output temperature even during peak usage, a significant advantage over less powerful, more budget-focused competitors. If you want a whole-house tankless experience that truly replaces a gas or large electric tank in any climate, this is the one you seriously consider.
Compared to a typical 18kW or 24kW unit, you gain a flow rate stability that is unmatched. While the massive electrical requirements (three dedicated 40A breakers) are a serious consideration and cost factor for installation, you are rewarded with true, reliable simultaneous hot water for multiple showers, a washer, and a dishwasher, even when your incoming ground water is frigid. This is the best whole-house tankless option for colder U.S. climates.
Technical Analysis
| Specification | Detail & U.S. Context | Analysis |
| Power Rating | 28.8 kW @ 240V | Maximum electric power available; necessary for whole-house use in cold climates (35-45°F incoming water). |
| Voltage/Amperage | 240V / Requires (3) 40A dedicated double-pole breakers (120A total) | The most substantial electrical requirement in the category, often requiring a full electrical service upgrade in older U.S. homes. |
| Advanced Flow Control | Fully automatic adjustment of flow rate to maintain set temperature. | A premium feature ensuring zero "cold water sandwich" or temperature drops during heavy, simultaneous use. |
| Flow Rate | Up to 5.0 GPM (at low temp rise); 2.5 GPM (at 60°F temp rise) | Provides true simultaneous hot water for two or three fixtures, making it comparable to gas heaters in performance. |
| Thermal Efficiency | 99% Energy Efficiency | Industry-leading efficiency; virtually all electricity consumed is converted directly into heat. |
| Design/Display | Sleek European design with back-lit, digital temperature display. | High-quality aesthetics and easy, precise temperature setting. No complex Wi-Fi app needed for core functions. |
1. Advanced Flow Control for Consistent Experience
The signature feature of the Stiebel Eltron Tempra 29 Plus Tankless Water Heater is its Advanced Flow Control (AFC). This isn't just a marketing term; it's a critical technology for the U.S. consumer who demands consistency. In a conventional tankless heater, if you open a third faucet and exceed the unit's heating capability, the water temperature will drop rapidly.
With AFC, the heater senses this sudden increase in demand and automatically, and slightly, reduces the overall water flow rate to maintain the set output temperature. You might notice a slight reduction in pressure, but you will not experience a sudden blast of cold water. For a family running multiple showers, this consistency is a premium, non-negotiable benefit that elevates the Tempra 29 Plus above its peers.
2. Substantial Electrical Requirements and Installation
You must be prepared for the electrical demands of this 28.8kW powerhouse. It requires a staggering total of 120 Amps, split across three dedicated 40A double-pole breakers. For many older U.S. homes with a 100A or 150A main service panel, installing the Tempra 29 Plus will necessitate a costly, comprehensive service upgrade to 200A.
While this adds to the overall cost, you are buying the necessary capacity to heat frigid water rapidly. It's crucial to consult a licensed electrician early in the process. The unit itself is relatively compact for its power, but the heavy-gauge wiring required will take up significant space and must be meticulously installed to code, which contributes to the unit's higher overall installed cost.
3. Cold Climate and High-Demand Performance
This is the tankless heater engineered for the entire United States, particularly the Northern tier where ground water temperatures in winter can hover around 35-40°F. At a 60°F temperature rise (e.g., from 40°F to a comfortable 100°F), the Tempra 29 Plus can still deliver a whole-house-level flow rate of 2.5 GPM. This is a game-changer for homeowners in these climates who want to avoid gas.
The unit’s 99% efficiency is also key. Almost no energy is lost, making it an extremely efficient appliance despite its high power draw. If you are a homeowner seeking the absolute best in electric tankless performance to run multiple fixtures and ensure everyone has a hot shower in the dead of winter, the sheer capacity and stability of this Stiebel Eltron model justify the high installation and purchase price.
User Profiles
1. High-Demand Luxury Homeowner
You own a modern, large home (3,000+ sq ft) in a colder state like New York or Michigan with a jetted tub and a multi-head shower system in the master bath. You prioritize unlimited hot water and consistent performance.
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Use Case: You expect to run the washing machine, a dishwasher, and a master shower simultaneously without any temperature drop or change in flow. You need an electric solution to avoid complex gas venting.
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The Fit: The 28.8kW capacity and the Advanced Flow Control are specifically designed for your high-demand, cold-climate needs. The unit can maintain the set temperature perfectly, even when supplying a high-volume fixture like a Roman tub, making it the perfect choice for a true luxury experience.
2. Northern Contractor/Developer
You build high-end residential homes in the snowy regions of the Rockies or the Northeast. You need a reliable, high-performance appliance that meets the tough energy codes and provides a superior homeowner experience.
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Use Case: You need to install a water heater that can reliably provide 4+ GPM of hot water in sub-freezing conditions and has a reputation for minimal callbacks and high durability.
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The Fit: The Stiebel Eltron brand is recognized for its quality and durability. The Tempra 29 Plus is one of the few electric models that can genuinely handle a modern, high-flow fixture in the cold, allowing you to market the home with the prestige of "unlimited, on-demand hot water."
3. Energy-Conscious Suburbanite
You are an environmentally aware homeowner who wants to move away from fossil fuels (gas) but lives in a climate that still experiences cold winters (e.g., Chicago suburbs). You want high efficiency and zero emissions.
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Use Case: You are committed to an all-electric home but refuse to sacrifice the comfort of reliable, strong hot water flow in the winter. You are willing to pay for the electrical upgrade now for the long-term benefit of a high-efficiency system.
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The Fit: The 99% energy efficiency of the Tempra 29 Plus aligns with your goals for a sustainable home. You get the superior flow and consistent temperature you need to make the switch from gas without any performance anxiety when the temperature drops to single digits.
"Complementary HomeTechCorner Category Recommendations"
| Recommended Products | Why This Category Is Useful Specifically for This Product | Short Usage Scenario |
| Smart Leak Detectors | This high-power unit is a significant investment; a detector near the multiple plumbing connections offers peace of mind against unforeseen leaks. | You install a leak sensor under the unit in your utility room so you get an alert the moment a connection starts to weep due to pressure changes. |
| Water Shut Off Valves | Since this unit handles the entire house's hot water, a smart valve allows you to remotely shut down the whole system's water supply in an emergency. | You are traveling abroad, and a burst pipe warning prompts you to shut off the entire house's main water line with a single tap on your phone. |
| Power Backup Solutions | Due to the high-amperage, an emergency UPS can protect the sensitive electronics and control board from costly power surges or brownouts common in the U.S. | A severe lightning storm causes a power surge, but the UPS takes the hit, saving the $800 control board from being fried. |
| Smart Wall Controllers | A dedicated wall controller can provide a convenient, pre-set 'Eco Mode' or 'Boost Mode' for the water heater without opening the utility closet. | Before you step into your multi-head shower, you tap a button on the wall to ensure the water heater is set to its highest performance profile. |
| Environmental Sensors Temp Humidity | These are essential for monitoring the environment in the closet or basement where the high-heat unit is installed, ensuring proper operating conditions. | You place a temperature sensor near the unit to confirm the room isn't getting too hot, which could shorten the unit's lifespan. |