Tankless electric hot water heaters offer a modern, energy-efficient alternative to traditional tank water heaters. These units heat water only as needed, providing endless hot water while saving space and reducing energy costs. Below is a comparison table featuring the top five tankless electric water heaters based on capacity, features, and user efficiency.
| Product | Brand | Power & Voltage | Flow Rate | Special Features |
|---|---|---|---|---|
| EcoSmart ECO 11 Electric Tankless Water Heater | EcoSmart | 13KW, 240V | On-Demand (variable) | Self-modulating technology, 99% thermal efficiency, space-saving design |
| Rheem 18kW 240V Tankless Electric Water Heater | Rheem | 18KW, 240V | Up to 4.4 GPM | Digital thermostatic control, advanced self-modulation, copper heating elements |
| Orbek 18kW Tankless Water Heater Electric | Orbek | 18KW, 240V | Up to 4.17 GPM | Quick heating, 98% efficiency, ETL certified, multi-protection system |
| Rheem 11kW 240V Tankless Electric Water Heater | Rheem | 11KW, 240V | Up to 2.68 GPM | Digital temperature display, self-modulating power control |
| Ranein 18kW 240V Tankless Electric Water Heater | Ranein | 18KW, 240V | Up to 4.3 GPM | High thermal efficiency, saves up to 60% heating costs, compact design |
EcoSmart ECO 11 Electric Tankless Water Heater
The EcoSmart ECO 11 delivers endless hot water on demand with its patented self-modulating technology that adjusts energy consumption based on water flow. It is highly efficient, reaching 99% thermal energy efficiency, making it ideal for saving electricity while providing consistent water temperature within 1 degree of the selected setting. Its compact size (11.5 x 8 x 3.75 inches) allows easy wall mounting or installation near points of use, saving space compared to traditional tanks. Rated at 13KW and 240 volts, it draws 54 amps and is suitable for small households or individual bathroom use. This model continuously monitors water temperature and flow rates to maintain reliable hot water supply without overheating or waste.
Rheem 18kW 240V Tankless Electric Water Heater
Rheem’s 18kW tankless electric water heater offers a robust solution for whole-house hot water needs. Operating at 240 volts, it supports flow rates up to 4.4 gallons per minute (GPM), suitable for multiple point-of-use simultaneously. Equipped with a durable copper immersion heating element, this model features an external LED digital thermostatic control with +/- 1 degree accuracy, allowing precise temperature regulation. Its advanced self-modulation adjusts power usage dynamically to meet fluctuating hot water demands, enhancing energy savings. The unit is also field-serviceable which improves maintenance and longevity. This Rheem model is a good choice for families requiring efficient, consistent hot water supply with smart controls.
Orbek 18kW Tankless Water Heater Electric
The Orbek 18kW tankless water heater delivers rapid hot water on demand with up to 4.17 GPM, covering 2-3 usage points simultaneously in a home. Thanks to its water-electricity separation technology, it reduces scale buildup and corrosion, ensuring longer lifespan and more efficient operation. This unit achieves an impressive 98% energy efficiency, significantly lowering electricity costs by up to 60%. It heats water within 3 seconds and is ETL certified for safety. Orbek also includes comprehensive security features such as leakage detection, over-temperature protection, high voltage safeguards, and dry heating prevention to protect users and the unit itself.
Rheem 11kW 240V Tankless Electric Water Heater
This 11kW model by Rheem is designed for smaller scale hot water demands, ideal for single bathrooms or point-of-use applications. It operates at 240 volts with a flow rate of up to 2.68 GPM. The unit features an ON/OFF dial control paired with an adjustable digital temperature display to tailor hot water to your preference. Its self-modulating power control optimizes energy consumption according to real-time hot water needs. Compact and efficient, this water heater balances convenience with reliable performance in limited space.
Ranein 18kW 240V Tankless Electric Water Heater
The Ranein 18kW tankless electric water heater operates with a high thermal efficiency of up to 99%, delivering continuous hot water for 2-3 usage points at flow rates up to 4.3 GPM. It eliminates the need for preheating, unlike traditional tanks, thus saving up to 60% on heating costs by consuming energy only when needed. This compact model fits easily into limited spaces and requires 240 volts with specific circuit breaker setups for installation. It offers stable temperature output and space-saving benefits, making it suitable for whole-house shower use or multiple hot water outlets.
Buying Guide For Tankless Electric Hot Water Heaters
Purchasing the right tankless electric water heater requires consideration of several important factors to ensure it matches your home’s hot water needs and installation capabilities.
Power Rating and Voltage
The kilowatt (KW) rating determines the heating capacity of the unit. Higher KW models deliver greater flow rates and support larger households with multiple simultaneous hot water demands. For most whole-house applications, models between 18kW and 24kW at 240 volts are common. Smaller units (around 11kW to 13kW) are suited for point-of-use or single bathroom setups.
Flow Rate (GPM)
Gallons per minute (GPM) indicates the water volume the heater can supply at a desired temperature rise. Typical household showers require about 2.5 GPM each, so calculate total flow based on simultaneous usage points. Select a model that comfortably exceeds your peak hot water demand to avoid temperature fluctuations.
Energy Efficiency
Look for models with self-modulating technology, which adjusts energy consumption based on hot water demand, reducing electricity waste. Units with 90% or higher thermal efficiency will save money on energy bills.
Installation Size & Space
Tankless units are compact, but ensure the model fits where you plan to install—such as wall-mounted in utility rooms, under sinks, or near points of use. Consider clearance, water connections, and electrical requirements.
Temperature Control & Features
Digital thermostats with precise temperature control (+/- 1 degree) improve user comfort. Extra features like LED displays, remote or Wi-Fi control, and safety protections (overheat and leak detection) enhance operation and safety.
Certification & Safety
Choose models that are ETL or UL certified to ensure compliance with safety standards. Safety features like dry heating protection and leakage alerts reduce risks and increase reliability.
Electrical Requirements
Check your home’s electrical panel for availability of the required voltage and amperage. High KW units need appropriate circuit breakers and wiring, sometimes involving professional installation.