Finding a large electric water heater that reliably supplies hot water for the entire home can be a challenge. This guide highlights top electric tankless and small-tank options designed for high-demand households. Each product is reviewed for performance, installation considerations, and energy efficiency. The selection focuses on models suitable for multiple use points, while balancing space needs and power requirements. Use the Buying Guide below to compare features and make an informed choice for steady hot water.
| Product | Type | GPM / Power | Key Benefit |
|---|---|---|---|
| Rheem 18kW Tankless | Tankless | Up to 4.4 GPM | Compact, precise temp control |
| Rheem RTEX-24 | Tankless | 24 kW, 240V | High flow, adjustable temp |
| EcoSmart ECO 11 | Tankless | 13 kW @ 240V | Space-saving, energy efficient |
| Stiebel Eltron Tempra 29 Plus | Tankless | Up to 28,800 watts | Premium efficiency, compact |
| WINTEMP 27kW | Tankless | 27 kW @ 240V | High capacity, WiFi control |
Rheem 18kW 240V Tankless Electric Water Heater
Rheem’s 18kW tankless heater features an external digital thermostat with an LED display, offering ±1 degree accuracy. Its self-modulation adjusts power to meet demand, helping maintain consistent temperatures. Copper immersion heating elements are field serviceable, and the unit is designed for reliable performance with a flow rate up to 4.4 GPM. This model is well-suited for point-of-use installations or small to mid-size homes where space is at a premium and a steady supply of hot water is needed.
Rheem RTEX-24 24kW 240V Tankless Water Heater
Rheem RTEX-24 delivers strong performance for whole-home use with continuous hot water. It requires three 40-amp double-pole breakers and a 200-amp service recommended by most installations. The unit supports precise temperature control with a dial and adjustable digital display from 80 to 140 degrees Fahrenheit. Groundwater temperature and geographic location influence gallons per minute and temperature rise, so plan accordingly for peak hot-water demand across multiple fixtures.
EcoSmart ECO 11 Electric Tankless Water Heater
The EcoSmart ECO 11 is a compact tankless heater designed to save space and energy. With a 13 kW rating at 240 volts, it offers endless on-demand hot water and maintains temperature within about 1 degree of the target setting. Its small footprint—about 11.5 x 8 x 3.75 inches—makes it ideal for wall mounting or point-of-use installation, reducing energy waste by heating water only when needed.
Stiebel Eltron Tempra 29 Plus
The Tempra 29 Plus provides continuous hot water on demand and a compact, vent-free design. It features two temperature memory presets for quick adjustments to personal preferences. Requires hard-wired 240V or 208V service, with a maximum draw of up to 28,800 watts at 240V. It’s a solid choice for households needing reliable heating with minimal footprint and straightforward installation.
WINTEMP 27kW Tankless Water Heater
The WINTEMP 27kW unit is designed for whole-house performance with a maximum output of about 6.5 GPM. It requires three 40A double-pole breakers and 3 x 8 AWG wiring with a recommended 250A service. It features energy-saving self-regulating technology that adjusts power usage based on flow and temperature, delivering stable temperatures and reduced energy spend, especially in homes with multiple simultaneous hot-water demands.
Buying Guide
Key considerations help determine the best choice for a large electric water heater. First, evaluate your peak hot-water load. Homes with multiple showers, dishwashers, and laundry cycles may benefit from higher-GPM tankless units or a combination of point-of-use heaters and a main unit. Second, check electrical capacity. Tankless models demand significant amperage, often requiring a dedicated sub-panel or electrical upgrades. Third, space and installation location matter; compact models save closet space, while wall-mounts and under-sink options suit tight layouts. Fourth, consider temperature control features. Digital displays, precise increments, and memory presets improve comfort and consistency. Finally, factor maintenance and serviceability. Units with field-serviceable elements reduce downtime and repair costs.
Performance versus efficiency is a continuous trade-off. Higher power heaters deliver more immediate hot water but require robust electrical systems. Self-modulating or demand-based systems improve energy efficiency by heating water only when needed. For households with variable hot-water use or space limitations, a combination approach—such as a main high-capacity unit paired with point-of-use heaters—can balance both performance and energy savings.
Installation conditions also influence choice. In colder climates, water temperature at the inlet may demand higher flow rates to prevent cold-water sandwich effects. Always verify that your home’s electrical service, available space, and water piping align with a unit’s specifications before purchasing. Consulting a licensed electrician or plumber helps ensure safety, compliance, and optimal performance.
In summary, these options cover a range of needs—from compact, energy-efficient tankless choices like EcoSmart ECO 11 to high-capacity models like the WINTEMP 27kW. Each product provides robust hot-water performance with varying power requirements and installation needs. Selecting the right model depends on your household’s hot-water demand, electrical readiness, and space constraints.