Best Electric Tankless Water Heaters | Find Yours Now!
Best Electric Tankless Water Heaters: Never Take a Cold Shower Again
The definitive guide to choosing the perfect electric tankless water heater for your home
I’ve been on countless jobs where a family’s biggest complaint is the morning scramble for hot water. You know the drill — someone takes a long shower, and suddenly everyone else is left with lukewarm disappointment. A tankless system solves that overnight.
After decades in the plumbing trade and testing hundreds of units, I can tell you that electric tankless water heaters have come a long way. They’re not just space-savers anymore — they’re legitimate game-changers for homes ready to embrace endless hot water.
The best electric tankless water heaters combine German engineering precision with American reliability. Because they use self-modulating technology, these heaters only consume the exact energy needed, which leads to significant monthly savings on your utility bills.
Why Electric Tankless Makes Sense
- No venting required (unlike gas models)
- 99% energy efficiency rating
- Space-saving wall-mount design
- Lower upfront installation costs
- Perfect for apartments and condos
Tankless Water Heater Showdown: The Lineup at a Glance
| Product | Rating | Power | Flow Rate | Price* | Best For |
|---|---|---|---|---|---|
| Stiebel Eltron Tempra 29 Trend | 4.5/5 (2,133) | 28.8 kW | 5.7 GPM | $644* | Whole House |
| EcoSmart ECO 27 | 4.2/5 (3,011) | 27 kW | 6.6 GPM | $518* | Best Value |
| Rheem RTEX-24 | 4.3/5 (827) | 24 kW | 5.9 GPM | $508* | Cold Climates |
| Stiebel Eltron Tempra 24 Plus | 4.4/5 (809) | 24 kW | 5.0 GPM | $673* | Premium Choice |
| EcoSmart ECO 18 | 4.3/5 (2,020) | 18 kW | 4.4 GPM | $395* | Point of Use |
*Price at the Time of Publication
Climate & Sizing Guide: Finding Your Perfect Match
Temperature Rise Calculator
U.S. Groundwater Temperatures
Formula: Desired Temperature (120°F) – Ground Water Temperature = Temperature Rise Needed
Example: Minneapolis (45°F ground water)
120°F – 45°F = 75°F rise needed
GPM Requirements
- Kitchen Sink: 0.5-1.0 GPM
- Bathroom Sink: 0.5 GPM
- Shower: 2.0-2.5 GPM
- Dishwasher: 1.0-1.5 GPM
- Washing Machine: 1.5-2.0 GPM
Pro Tip: Add up simultaneous uses for your total GPM need
In-Depth Electric Tankless Water Heater Reviews
Stiebel Eltron Tempra 29 Trend – Best Overall
This German-engineered powerhouse represents the gold standard in electric tankless technology. After installing dozens of these units, I can confidently say the Tempra 29 delivers consistent performance that rivals much more expensive systems.
Pros
- • Advanced flow control technology
- • Self-modulating power system
- • LED temperature display
- • 7-year leak warranty
- • Silent operation
Cons
- • Higher upfront cost
- • Requires 240V electrical setup
- • Large electrical demand (120A)
Key Specifications
“This is an absolutely amazing water heater. I replaced my propane-tanked water heater with this. It produces hot water on demand, limited only by your water supply. Not only am I impressed, but was also shocked and highly satisfied with this machine’s performance.” – Andrew S., Verified Amazon Customer
EcoSmart ECO 27 – Best Value Champion
The ECO 27 proves you don’t need to break the bank for reliable tankless performance. This unit has powered countless American homes, though it requires careful sizing to match your specific needs.
Pros
- • Excellent value proposition
- • Self-modulating technology
- • Compact wall-mount design
- • Digital temperature control
- • Lifetime residential warranty
Cons
- • Performance varies in cold climates
- • Some quality control issues
- • Customer service concerns
Key Specifications
“We bought an ECO 27k about 3.5 years ago and it’s been great. We live in VA and it works perfectly for our 2,800 sq ft home with 3 bedrooms and 2 baths.” – Verified Amazon Customer
Rheem RTEX-24 – Cold Climate Specialist
Rheem’s reputation for reliability shines through in the RTEX-24. This unit excels in challenging conditions where consistent performance matters most — particularly in northern climates where ground water runs cold.
Pros
- • Excellent cold climate performance
- • Self-modulating technology
- • Robust copper elements
- • 99.8% energy efficiency
- • Strong brand reputation
Cons
- • Lower flow rate than competitors
- • Basic digital display
- • Installation complexity
Key Specifications
“Installed this unit under the kitchen sink and it supplies both the main sink and the island sink. The great thing about this heater is that it is self-modulating. It senses the temp of the incoming water and adjusts the heating elements.” – Arizona Customer, Amazon Review
Stiebel Eltron Tempra 24 Plus – Premium Engineering
The Tempra 24 Plus brings German precision engineering at a more accessible price point. It’s the unit I recommend when clients want Stiebel Eltron quality but have moderate hot water demands.
Pros
- • Advanced flow control
- • German engineering quality
- • Precise temperature control
- • Durable construction
- • 7-year warranty
Cons
- • Premium pricing
- • Lower flow rate than ECO 27
- • Complex installation requirements
Key Specifications
EcoSmart ECO 18 – Point-of-Use Champion
Perfect for targeted applications like master bathroom suites or kitchen islands. The ECO 18 delivers impressive performance for smaller loads while maintaining EcoSmart’s value-focused approach.
Pros
- • Excellent for point-of-use
- • Affordable price point
- • Easy installation
- • Compact footprint
- • Lifetime warranty
Cons
- • Limited whole-house capability
- • Performance drops in winter
- • Basic feature set
Key Specifications
“Exactly what I needed for a bathroom, small kitchen and washer. Mounts inside, no gas line, no exhaust or vent needed, and surprisingly no noise and plenty of hot water.” – Alberto M., Amazon Customer
The Real-World Performance Test: Beyond the Spec Sheet
After testing these units in various climates and home configurations, three models consistently outperformed expectations in real-world scenarios:
Temperature Rise Reality Check
Don’t just look at maximum GPM ratings. The key metric is GPM at your required temperature rise. A unit rated for 6 GPM might only deliver 3 GPM when heating 45°F water to 120°F in Minnesota winters.
The Perfect Tankless Heater For You: A Quick-Pick Guide
Whole House Champion
Large family, multiple bathrooms, high hot water demand
Premium performance, advanced flow control
Cold Climate Hero
Northern states, cold ground water, consistent performance needed
Proven reliability in challenging conditions
Budget Champion
Best value, moderate usage, warm climate
Unbeatable price-to-performance ratio
Premium Pick
Quality-focused, German engineering, long-term investment
Superior build quality and precision
Point-of-Use Expert
Single bathroom, kitchen sink, targeted installation
Perfect for specific applications
Apartment/Condo
Space-limited, moderate usage, easy installation
Compact design, simple setup
Final Verdict & The “Perfect Heater” Finder
Find Your Perfect Match in 3 Questions
1. What’s your primary hot water usage?
Your Perfect Match:
Pro Homeowner Tips: Getting the Most From Your Unit
Installation Essentials
- • Always hire a licensed electrician for 240V work
- • Upgrade your electrical panel if needed (most units require 100-120A)
- • Install dedicated circuits for each unit
- • Consider a whole-home surge protector
- • Mount as close to main usage points as possible
Maintenance Made Easy
- • Descale annually in hard water areas (every 6 months in severe cases)
- • Use white vinegar for eco-friendly descaling
- • Check inlet filter screens monthly
- • Keep area around unit clear for airflow
- • Schedule professional maintenance every 2-3 years
Temperature Optimization
- • Set temperature to 120°F for optimal efficiency
- • Install low-flow showerheads and faucet aerators
- • Use cold water for washing clothes when possible
- • Insulate hot water pipes to reduce heat loss
- • Consider a recirculation pump for instant hot water
Warranty Protection
- • Register your unit immediately after installation
- • Keep all installation receipts and permits
- • Use only licensed professionals for installation
- • Follow manufacturer maintenance schedules
- • Document any service calls or repairs
Frequently Asked Questions
Are electric tankless water heaters worth it?
Yes, electric tankless water heaters are worth it for most homes. They provide endless hot water, save 30-50% on water heating costs, last 15-20 years (vs 8-12 for tank heaters), and free up valuable floor space. The energy savings alone typically pay for the unit within 3-5 years.
How do I choose the right size electric tankless water heater?
Calculate your peak hot water demand in GPM, then factor in your ground water temperature. Add up simultaneous uses (shower = 2.5 GPM, sink = 0.5 GPM, etc.). In cold climates, choose a unit with 20-30% more capacity than calculated to handle temperature rise demands.
What’s the difference between electric vs gas tankless water heaters?
Electric units are easier to install (no venting required), have lower upfront costs, and work great for moderate usage. Gas units provide higher flow rates and work better in very cold climates, but require professional venting installation and access to natural gas or propane.
Do electric tankless water heaters work in cold climates?
Yes, but choose your unit carefully. Models like the Rheem RTEX-24 and Stiebel Eltron Tempra series are specifically designed for cold climate performance. The key is selecting adequate kW capacity to handle the larger temperature rise needed in northern climates.
How much does it cost to install an electric tankless water heater?
Installation typically costs $500-1,500, depending on electrical upgrades needed. Most homes require electrical panel upgrades ($500-1,000) and dedicated 240V circuits ($200-500). Professional installation is essential and often required for warranty validation.
What maintenance do electric tankless water heaters need?
Annual descaling is the main requirement, especially in hard water areas. This involves flushing the system with vinegar or commercial descaling solution. Professional maintenance every 2-3 years helps ensure optimal performance and warranty compliance.
How We Chose These Tankless Water Heaters
Our selection process prioritizes real-world performance over marketing claims. We evaluated each electric tankless water heater based on:
Customer Satisfaction
- • Minimum 4.0-star Amazon rating
- • At least 500 verified customer reviews
- • Analysis of both positive and negative feedback
- • Long-term reliability reports
Technical Performance
- • Energy efficiency ratings
- • Flow rate vs temperature rise capability
- • Self-modulating technology presence
- • Build quality and component durability
Professional Installation Experience
As licensed professionals, we’ve installed and serviced hundreds of these units. Our recommendations reflect hands-on experience with installation complexity, reliability over time, and customer satisfaction in diverse climates and applications.
