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10 Best Whole House Tankless Electric Hot Water Heaters 2025 in the United States
#1
Winner
Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric, On Demand Hot Water, Eco, White, 20.2
The Stiebel Eltron Tankless Water Heater – Tempra 24 Plus is a robust option for homeowners looking for an electric solution to efficiently provide hot water on demand. With a flow rate of 4.0 GPM and the ability to maintain a temperature rise of up to 140°F, it can comfortably supply hot water for multiple outlets simultaneously, making it suitable for larger households. Its eco-friendly design incorporates advanced flow control technology, which adjusts the water flow to maintain a consistent temperature, ensuring that you won’t be left with a cold shower.
Rating
9.9
Chosen by1,325
Flow Rate (GPM)
Temperature Rise
Power (kW)
Most important from
2107 reviews
#3
Ranein Electric Tankless Water Heater, 18kW 240V on Demand Instant Endless Water Heater with LED Temperature Display for Residential Whole House Shower, Space Saving
The Ranein Electric Tankless Water Heater is designed to provide instant and endless hot water for a whole house, making it suitable for residential use. With a power rating of 18 kW and a flow rate of up to 4.3 gallons per minute (GPM), it can effectively supply hot water to 2-3 usage points simultaneously. The unit offers a high energy efficiency of 99%, which helps in reducing heating costs by up to 60% compared to traditional tank-type water heaters.
Rating
9.6
Energy Efficiency
Installation Requirements
Most important from
115 reviews
Top 10 Best Whole House Tankless Electric Hot Water Heaters 2025 in the United States
#1
Winner
Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric, On Demand Hot Water, Eco, White, 20.2
Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric, On Demand Hot Water, Eco, White, 20.2
Flow Rate (GPM): 4.0
Temperature Rise: 140°F
Power (kW): 24
Energy Efficiency: Energy Efficient
Installation Requirements: 150 A electric service
Warranty: 7-year leakage, 3-year parts
Chosen by 1325 this week
Ranein Electric Tankless Water Heater, 18kW 240V on Demand Instant Endless Water Heater with LED Temperature Display for Residential Whole House Shower, Space Saving
Ranein Electric Tankless Water Heater, 18kW 240V on Demand Instant Endless Water Heater with LED Temperature Display for Residential Whole House Shower, Space Saving
Flow Rate (GPM): 4.3
Temperature Rise: 86°F to 131°F
Power (kW): 18
Energy Efficiency: 99%
Installation Requirements: 240V, two 40-amp breakers
Rheem RTEX-24 24kW 240V Electric Tankless Water Heater, Gray
Rheem RTEX-24 24kW 240V Electric Tankless Water Heater, Gray
Flow Rate (GPM): 5.9
Power (kW): 24
Energy Efficiency: 99.8%
Installation Requirements: Wall Mount, 240V
Related Products
EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW - Quantity 1, 17 x 17 x 3.5
EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW - Quantity 1, 17 x 17 x 3.5
Flow Rate (GPM): 2.7 to 6.5
Power (kW): 27
Energy Efficiency: 99%
Installation Requirements: Three 40 AMP double pole breakers
Warranty: Limited Lifetime Warranty on electronics
WINTEMP Electric Tankless Water Heater 36KW 240V Endless On Demand Instant Endless Water Heater Suitable for Residential Whole House Shower Self Regulating Technology with WIFI Remote Control ETL
WINTEMP Electric Tankless Water Heater 36KW 240V Endless On Demand Instant Endless Water Heater Suitable for Residential Whole House Shower Self Regulating Technology with WIFI Remote Control ETL
Flow Rate (GPM): 3.6 to 8.7
Temperature Rise: 86°F to 140°F
Power (kW): 36
Energy Efficiency: up to 99%
Installation Requirements: 4 x 40 Amp DP breakers
Electric Tankless Water Heater WINTEMP, 27kW 240V Whole House Hot Water Supply Shower on Demand Instant Endless Water Heater with LED Temperature Display and WIFI Control, Space-Saving ETL
Electric Tankless Water Heater WINTEMP, 27kW 240V Whole House Hot Water Supply Shower on Demand Instant Endless Water Heater with LED Temperature Display and WIFI Control, Space-Saving ETL
Flow Rate (GPM): 2.7 to 6.5
Temperature Rise: 86°F to 140°F
Power (kW): 27
Energy Efficiency: High Efficiency
Installation Requirements: 240V, three 40 Amp breakers
#10
Rheem RTEX-27 240V 3 Heating Chambers Residential Tankless Water Heater
Rheem RTEX-27 240V 3 Heating Chambers Residential Tankless Water Heater
Flow Rate (GPM): 0.11
Power (kW): 27
Energy Efficiency: High
Installation Requirements: 240-volt, 3/4 inch NPT, threaded fittings
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Buying Guide for the Best Whole House Tankless Electric Hot Water Heaters
Choosing the right whole-house tankless electric hot water heater can significantly impact your home's comfort and energy efficiency. These systems provide hot water on demand, which means you won't run out of hot water and you can save on energy costs since they don't maintain a reservoir of hot water. However, selecting the right model involves understanding several key specifications to ensure it meets your household's needs. Here’s a guide to help you navigate through the essential specs and make an informed decision.Flow Rate (GPM)Flow rate, measured in gallons per minute (GPM), indicates how much hot water the unit can deliver at a time. This is crucial because it determines whether the heater can handle multiple hot water demands simultaneously, such as running a shower and a dishwasher. For smaller households with fewer simultaneous hot water needs, a lower GPM (around 3-5 GPM) may suffice. Larger households or those with higher hot water demands should look for units with higher GPM (6-10+ GPM). Assess your household's peak hot water usage to choose the right flow rate.
Temperature RiseTemperature rise refers to the increase in water temperature the unit can achieve. This is important because it affects how hot the water will be when it reaches your taps. The required temperature rise depends on your incoming water temperature and your desired output temperature. For instance, if your incoming water is 50°F and you want it at 120°F, you need a unit that can handle a 70°F rise. Colder climates may require units with higher temperature rise capabilities. Consider your local water temperature and your preferred hot water temperature to determine the necessary temperature rise.
Power (kW)The power rating, measured in kilowatts (kW), indicates the electrical power the unit uses to heat water. Higher kW ratings generally mean the unit can heat water more quickly and handle higher flow rates. Units typically range from 18 kW to 36 kW or more. Smaller households with lower hot water demands can opt for units on the lower end of the spectrum, while larger households or those with higher demands should consider higher kW ratings. Ensure your home's electrical system can support the power requirements of the unit you choose.
Energy EfficiencyEnergy efficiency measures how effectively the unit converts electrical energy into hot water, often expressed as a percentage. Higher efficiency means lower energy waste and reduced operating costs. Look for units with efficiency ratings of 90% or higher for the best performance. Consider your long-term energy savings and environmental impact when evaluating efficiency.
Installation RequirementsInstallation requirements include the electrical and space considerations necessary for setting up the unit. Tankless electric water heaters often require specific voltage and amperage, as well as adequate space for ventilation and maintenance. Ensure your home’s electrical system can accommodate the unit’s requirements, and that you have enough space for proper installation. Consulting with a professional installer can help you understand these needs and avoid potential issues.
WarrantyThe warranty provides an indication of the unit’s reliability and the manufacturer’s confidence in their product. Longer warranties can offer peace of mind and protection against defects or failures. Warranties typically range from 5 to 15 years. Consider how long you plan to stay in your home and your comfort level with potential repair costs when evaluating warranty options.