10 Best Electric On Demand Water Heater 2026 in the United States
#1
Winner
Rheem RTEX-24 24kW 240V Electric Tankless Water Heater, Gray
The Rheem RTEX-24 Electric Tankless Water Heater is a solid choice for those looking for on-demand hot water. With a power output of 24kW and a flow rate of up to 5.9 gallons per minute (GPM), it offers consistent and continuous hot water supply, making it suitable for medium to large households.
Rating
10.0
Chosen by1,488
Energy Efficiency
Size and Installation Requirements
Most important from
4058 reviews
#2
Rheem 18kW 240V Tankless Electric Water Heater, Gray
The Rheem 18kW 240V Tankless Electric Water Heater is a solid option for those looking to efficiently supply hot water on demand. With a flow rate of up to 4.4 gallons per minute (GPM), it can cater to smaller households or applications requiring moderate hot water supply, making it ideal for apartments or homes with limited space.
Rating
9.4
Power (kW)
Temperature Rise
Size and Installation Requirements
Most important from
4058 reviews
#3
Stiebel Eltron Tankless Water Heater – Tempra 36 Plus – Electric, 36kW, On Demand Hot Water, Eco, White, Made in Germany
The Stiebel Eltron Tempra 36 Plus is a powerful electric tankless water heater delivering 36 kilowatts of heating power, which is quite high for on-demand water heating. It provides a flow rate of about 1.5 gallons per minute, making it suitable for smaller households or limited simultaneous hot water needs, but it might struggle to supply multiple large fixtures at once, like several showers running simultaneously. Thanks to its advanced flow control and self-modulation technology, it adjusts energy use based on demand, helping to save on electricity bills by avoiding unnecessary heating.
Rating
9.1
Flow Rate (GPM)
Power (kW)
Temperature Rise
Most important from
325 reviews
Top 10 Best Electric On Demand Water Heater 2026 in the United States
#1
Winner
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%
Size and Installation Requirements: 17.63"W x 18.25"H, Wall Mount
Chosen by 1488 this week
Rheem 18kW 240V Tankless Electric Water Heater, Gray
Rheem 18kW 240V Tankless Electric Water Heater, Gray
Flow Rate (GPM): 4.4
Power (kW): 18
Energy Efficiency: 99.8%
Size and Installation Requirements: 14.5"W x 18.25"H, wall-mounted
Stiebel Eltron Tankless Water Heater – Tempra 36 Plus – Electric, 36kW, On Demand Hot Water, Eco, White, Made in Germany
Stiebel Eltron Tankless Water Heater – Tempra 36 Plus – Electric, 36kW, On Demand Hot Water, Eco, White, Made in Germany
Flow Rate (GPM): 1.5 Gallons Per Minute
Power (kW): 36 Kilowatts
Energy Efficiency: High
Size and Installation Requirements: 16.63"W x 14.5"H, Wall mount
Stiebel Eltron Tankless Water Heater – Tempra 20 Plus – Electric, 19.2kW, On Demand Hot Water, Eco, White, Made in Germany
Stiebel Eltron Tankless Water Heater – Tempra 20 Plus – Electric, 19.2kW, On Demand Hot Water, Eco, White, Made in Germany
Flow Rate (GPM): 3.79 liters per minute
Power (kW): 19.2 kW
Energy Efficiency: auto-modulation, electronic flow control
Size and Installation Requirements: 16.63"W x 14.5"H, wall-mountable
Warranty and Support: 7 years leakage, 3 years parts
Stiebel Eltron Tankless Water Heater – Tempra 29 Plus – Electric, 28.8kW, On Demand Hot Water, Eco, White, Made in Germany
Stiebel Eltron Tankless Water Heater – Tempra 29 Plus – Electric, 28.8kW, On Demand Hot Water, Eco, White, Made in Germany
Flow Rate (GPM): 3 Gallons Per Minute
Power (kW): 28.8 KW
Energy Efficiency: High Efficiency
Size and Installation Requirements: 16.63"W x 14.5"H; Wall Mount; 240V
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Stiebel Eltron Tankless Water Heater - Tempra 29 Trend – Electric, 28.8kW, On Demand Hot Water, Eco, White, Made in Germany
Stiebel Eltron Tankless Water Heater - Tempra 29 Trend – Electric, 28.8kW, On Demand Hot Water, Eco, White, Made in Germany
Power (kW): 28.8 kW
Temperature Rise: 68°F to 140°F
Energy Efficiency: High
Size and Installation Requirements: 16.63"W x 14.5"H, Wall Mount
Warranty and Support: 7 years leaks, 3 years parts
#10
Rheem 3.5kW 120V Point of Use Thermostatic Tankless Electric Water Heater
Rheem 3.5kW 120V Point of Use Thermostatic Tankless Electric Water Heater
Flow Rate (GPM): 0.9 Gallons Per Minute
Power (kW): 3.5 kW
Energy Efficiency: Highly Efficient
Size and Installation Requirements: 10.88"W x 5.88"H, Wall mount
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Buying Guide for the Best Electric On Demand Water Heater
Choosing the right electric on-demand water heater can significantly improve your home's energy efficiency and ensure you have a reliable supply of hot water whenever you need it. These heaters only heat water as it is needed, which can save energy compared to traditional tank water heaters. To make an informed decision, you need to consider several key specifications that will determine the heater's performance and suitability for your needs.Flow Rate (GPM)Flow rate, measured in gallons per minute (GPM), indicates how much hot water the heater can produce at a time. This is important because it determines whether the heater can meet your household's hot water demands. Lower flow rates (1-3 GPM) are suitable for small households or single-point applications like a single shower or faucet. Medium flow rates (3-5 GPM) can handle multiple fixtures simultaneously, making them ideal for average-sized homes. Higher flow rates (5+ GPM) are necessary for larger homes with multiple bathrooms and high hot water usage. To pick the right flow rate, consider the number of people in your household and the number of hot water fixtures you expect to use at the same time.
Power (kW)The power rating, measured in kilowatts (kW), indicates the heater's capacity to heat water. Higher power ratings mean the heater can heat water more quickly and to higher temperatures. For small households or low hot water usage, a heater with a power rating of 10-15 kW may be sufficient. For average households, a power rating of 15-25 kW is typically adequate. Larger households or those with high hot water demands may require a heater with a power rating of 25-30 kW or more. Choose a power rating that matches your hot water needs and ensures the heater can keep up with your usage patterns.
Temperature RiseTemperature rise refers to the increase in water temperature that the heater can achieve. This is important because it affects how hot the water will be when it reaches your fixtures. A higher temperature rise means the heater can provide hotter water, which is essential in colder climates where incoming water temperatures are lower. For warmer climates or lower hot water needs, a temperature rise of 30-40°F may be sufficient. In colder climates or for higher hot water demands, look for a temperature rise of 50-70°F or more. Consider your local climate and desired water temperature when choosing the right temperature rise.
Energy EfficiencyEnergy efficiency indicates how effectively the heater converts electrical energy into hot water. Higher efficiency ratings mean lower energy consumption and reduced utility bills. Look for heaters with an energy efficiency rating of 90% or higher for the best performance. Some models may also have energy-saving features like modulating technology, which adjusts the power output based on the hot water demand. Choose a heater with high energy efficiency to save on energy costs and reduce your environmental impact.
Size and Installation RequirementsThe physical size of the heater and its installation requirements are important considerations, especially if you have limited space. Compact models are ideal for small spaces or point-of-use installations, while larger models may require more space and specific installation conditions. Check the dimensions of the heater and ensure you have enough space for installation. Additionally, consider the electrical requirements, such as voltage and amperage, to ensure your home's electrical system can support the heater. Choose a model that fits your available space and meets your installation requirements.
Warranty and SupportThe warranty and support provided by the manufacturer can give you peace of mind and protect your investment. A longer warranty period indicates the manufacturer's confidence in the product's durability and reliability. Look for heaters with warranties of at least 5-10 years on the heating elements and other major components. Additionally, consider the availability of customer support and service options in case you encounter any issues. Choose a heater with a strong warranty and reliable support to ensure long-term satisfaction and performance.