Best Electric Tankless Water Heaters for on-Demand Hot Water
Electric tankless water heaters provide on-demand hot water with compact design and energy-conscious operation. This guide highlights five top options, explaining who each is best for, why it was selected, and practical cautions. It helps buyers compare performance, space needs, and installation considerations so you can choose the right model for homes, apartments, or point-of-use setups.
Overview of top picks
| Product | Best For | Key Strength | Limitations |
|---|---|---|---|
| EcoSmart ECO 11 | Small homes or point-of-use | Self-modulating technology; compact on-demand heating | Lower flow in colder climates; may require multiple units for whole-house use |
| Rheem 11kW | Single-faucet upgrades or small apartments | Dial control with digital temp display; self-modulating | Limited flow at higher demands |
| Rheem RTEX-24 | Full home with higher hot-water needs | Higher power, more gallons per minute | Requires substantial electrical service and panel space |
| Orbek 14kW | Two to three point-of-use fixtures | LED display; 3.38 GPM, quick hot water | Electrical and circuit requirements high for whole-home use |
| Rheem 18kW | Homes needing higher flow | Strong flow up to 4.4 GPM; advanced self-modulation | Large electrical load; professional installation advised |
EcoSmart ECO 11 Electric Tankless Water Heater
The EcoSmart ECO 11 is a compact, energy-conscious option designed for point-of-use or small-space installations. It uses patented self-modulating technology to adjust heat output based on incoming water temperature and demand, helping conserve energy and minimize hot-water waste. This unit is best for single-faucet or small-sink setups in apartments, cottages, or under-sink installations where space is at a premium.
Why it’s selected: This model is among the smallest electric tankless heaters, enabling wall mounting and space-saving design. It is 99% thermally efficient since it heats water only when needed, not maintaining a tank full of hot water. Its 54-amp draw fits typical 240V circuits used in many homes.
Who it’s best for: Homeowners with limited space who want on-demand hot water at a single point or for low-flow use. Ideal for supplementing a larger system or for small apartments where full-house hot water demands are minimal.
Caution: Flow and temperature rise can be limited in colder climates or when several fixtures require simultaneous hot water. For larger households or multi-point use, consider higher-capacity models or multiple units.
Rheem 11kW 240V Tankless Electric Water Heater
The Rheem 11kW model provides straightforward control with an ON/OFF dial and a digital temperature display. It uses self-modulating power to adjust output as needed, making it an efficient option for smaller homes or apartments where hot water demand is modest. Flow rate and temperature stability are generally suitable for single-user or dual-use scenarios at moderate tap demands.
Why it’s selected: The dial control paired with a digital readout offers simple operation and precise adjustments. Self-modulating power helps prevent overshoot and reduces energy use compared with fixed-power units.
Who it’s best for: Buyers who want a simple, reliable unit for limited hot-water needs, especially in apartments or small homes where one or two fixtures use hot water at a time.
Caution: It may not deliver high GPM in cooler climates or when multiple fixtures demand hot water simultaneously. Consider a higher-capacity option for larger households.
Orbek 14kW Electric Tankless Water Heater
The Orbek 14kW model is designed for 240V operation with an emphasis on speed and efficiency. It is capable of delivering up to 3.38 GPM for use at two to three points of use. The LED digital display helps monitor settings, and the unit’s energy separation design aims to reduce scale and corrosion, contributing to longer-term efficiency.
Why it’s selected: It offers robust hot-water delivery for smaller multi-point setups and provides clear installation guidance and digital readouts for easy management. It emphasizes energy efficiency and rapid hot-water availability.
Who it’s best for: Homeowners needing reliable hot water at two to three fixtures without installing a full-home system, such as a couple of bathrooms or a kitchen plus a laundry area.
Caution: Requires careful electrical planning; ensure the home’s total circuit capacity supports 150 amps or more and verify breaker sizing with a professional installer.
Rheem 18kW 240V Tankless Electric Water Heater
The Rheem 18kW model targets higher hot-water demands with stronger flow. It features an external digital thermostatic control with LED display for precise temperature management, plus advanced self-modulation that adjusts power to meet real-time hot-water needs. Copper immersion elements offer durability, and the unit is designed to be field serviceable for maintenance or upgrades.
Why it’s selected: This model excels in homes requiring higher hot-water throughput, delivering up to 4.4 GPM in favorable conditions. Self-modulation helps balance energy use with demand while maintaining stable water temperature.
Who it’s best for: Households with multiple simultaneous hot-water points or higher daily usage where a higher-flow electric tankless option is beneficial.
Caution: Requires substantial electrical service and panel space. Installation should be performed by a qualified electrician to ensure safe operation and compliance with electrical codes.
Buying Guide
What to consider when choosing an electric tankless heater
- Household hot-water demand: Count the number of fixtures that will draw hot water at the same time. Higher GPM needs require higher-kW models or multiple units.
- Electrical service and panel capacity: Many units require 240V and 40–150A service. Confirm available capacity with a licensed electrician before purchasing.
- Flow rate vs. temperature rise: Real-world performance depends on incoming water temperature. Colder climates reduce achievable GPM at higher temperature rises.
- Installation location: Point-of-use installations save space but may limit capacity. Whole-home solutions need careful load planning and professional wiring.
- Energy efficiency: Self-modulating units adjust power to demand, improving energy use compared with constant-power heaters.
- Maintenance and serviceability: Look for units with accessible components and clear service instructions for easier maintenance over time.
Frequently Asked Questions
- Do electric tankless water heaters work well in cold climates?
They can, but performance depends on the incoming water temperature. In cold climates, a higher-capacity unit or multiple units at different locations may be necessary to maintain adequate flow and temperature. - Is installation complicated or dangerous?
Electric tankless heaters require proper electrical wiring, grounding, and adherence to local codes. A licensed electrician should perform installation and confirm panel capacity. - Can I install one unit for the whole house?
Yes, but it often requires a high-power unit and careful load calculations. In many cases, multiple units or a combination with a traditional heater may be preferred for reliability. - What maintenance is needed?
Regular descaling and inspection of connections help preserve performance. Some models offer easy access to heating elements for service. - What is self-modulating technology?
Self-modulating units automatically adjust heat output to match demand, improving energy efficiency and reducing standby losses compared to fixed-power models. - How do I choose between 11kW and 18kW models?
Consider your peak hot-water demand and panel capacity. Higher-kW units deliver more GPM but require more electrical service and space in the breaker panel.