Finding a reliable electric tankless water heater can deliver endless hot water on demand while saving space and energy. This guide highlights five top models, detailing their power, flow capabilities, installation needs, and efficiency features to help you compare options for apartments, small homes, or whole-house setups. Each option below supports multiple points of use and varies in wattage and flow rate to fit different hot-water demands and electrical systems.
| Product | Key Benefit | Approximate Flow Range |
|---|---|---|
| EcoSmart ECO 11 | Compact, energy-efficient, self-modulating | Up to 1.3 GPM |
| Rheem RTEX-24 | Powerful, adjustable temperature with LED display | Up to 4.0–4.4 GPM |
| Orbek 14kW | Efficient on-demand with 2-3 point-of-use support | Up to 3.38 GPM |
| WINTEMP 27kW | High capacity, stable temperature, WiFi control | |
| ECOTOUCH 27kW | Strong performance, user-friendly panel, safety protections |
EcoSmart ECO 11: Compact On-Demand Power
The EcoSmart ECO 11 delivers endless on-demand hot water with self-modulating technology. It continuously monitors water temperature and adjusts flow to keep water within one degree of the set temperature. With a 54 A amperage draw, this unit is designed for space-saving installation, often wall-mounted or at the point of use. EcoSmart emphasizes energy efficiency, claiming up to 99% thermal energy efficiency since water is heated only when needed and no standby heat is maintained.
Rheem 18kW 240V Tankless Electric Water Heater
Rheem’s model features an external digital thermostatic control with LED display for precise temperature management (+/- 1 degree). It uses self-modulation to adjust power to match hot-water demand and includes durable copper immersion elements that are field serviceable. This unit supports up to 4.4 GPM flow, making it suitable for multiple fixtures while maintaining consistent temperature and responsive performance.
Orbek 14kW 240V Tankless Water Heater
Orbek’s 14kW unit provides up to 3.38 GPM of on-demand hot water for 2–3 points of use, with guidance on electrical requirements including 240V/60A two-pole breakers and 1/2″ NPT water connections. The system emphasizes energy efficiency via water-electricity separation to minimize scale and corrosion, delivering hot water within seconds and offering potential electricity savings over traditional tank heaters.
Rheem RTEX-24 24kW 240V Tankless Water Heater
This model requires a robust electrical setup (three 40 Amp double-pole breakers and likely a 200 Amp service). It’s designed to deliver continuous hot water for whole-home use, with performance influenced by incoming water temperature. An easy-to-use ON/OFF dial and adjustable digital temperature display let you set temperatures in 1-degree increments from 80–140 degrees F, helping tailor heat output to your needs while maintaining reliability across units and locations.
Orbek 18kW 240V Tankless Water Heater
Orbek’s 18kW unit is designed for 240V operation with two 40A two-pole breakers and uses dual 8 AWG wires. It can provide up to 4.17 GPM for 2–3 fixtures, with rapid hot-water delivery and heat-management features aimed at reducing electricity use. The model highlights energy efficiency through separation of water and electricity and emphasizes reliable performance within seconds of demand.
WINTEMP 27kW Tankless Water Heater
The WINTEMP 27kW model offers up to 6.3 GPM with a stable, self-regulating temperature system. It requires three 40 Amp double-pole breakers and 3 x 8 AWG wiring, with 250A recommended power supply. A built-in LED temperature display and smart adjustments help maintain consistent heat, reduce energy waste, and support 2–4 usage points across the home, delivering dependable endurance for busy households.
ECOTOUCH 27kW On-Demand Water Heater
The ECOTOUCH 27kW on-demand heater features a 27kW heating system that delivers instant hot water at 125 ℉ or higher in seconds, with a flow rate up to 5.5 GPM. It includes a user-friendly touch panel and a clear display to monitor temperature and status. Safety protections cover leakage, over-temperature, high voltage, and dry-heating scenarios, while the design separates water and electrical lines to reduce leakage risk and scale buildup.
Buying Guide: Key Considerations For Electric Tankless Water Heaters
- Hot-water demand and flow rate: Calculate the number of fixtures and desired gallons per minute (GPM). Higher GPM models are better for whole-house use, while smaller apartments may only need 1–2 GPM at peak times.
- Electrical service: Check available amperage and circuit capacity. Many units require multiple dedicated breakers (often 2–3 x 40A or 3 x 40A). Ensure panel space and service amperage support the unit.
- Temperature rise and stability: Self-modulating units adjust output to maintain a steady temperature despite fluctuations in water temperature or flow. Look for units with precise temperature control (±1–2 degrees F).
- Installation location: Tankless heaters are compact but may need outdoor protection or indoor ventilation depending on model and local code. Wall-mounts free up floor space and simplify wiring.
- Energy efficiency: Many models emphasize on-demand heating with minimal standby power, which translates to energy savings over time. Compare energy-factor claims and customer reviews for real-world performance.
- Maintenance and parts availability: Field-serviceable elements and accessible replacement parts can reduce downtime. Copper immersion elements tend to be durable and easier to service.
- Safety features: Look for protections such as over-temp, leak detection, dry-fire protection, and proper ETL/UL certification to ensure compliance and safe operation in homes.
- Point-of-use vs. whole-house: Point-of-use models are ideal for single taps or sinks, while higher-wattage units can support multiple outlets if wiring and water supply allow.
