Best Electric Tankless Water Heaters for Quick Hot Water
If you need on-demand hot water without a bulky tank, an electric tankless water heater is a strong option. This guide highlights five top models, showing who each is best for and why. Ideal buyers include new home setups, point-of-use upgrades, or whole-home systems where space-saving and efficiency matter. The table below summarizes key picks to help you compare at a glance.
| Product | Best For | Approx. GPM | Key Benefit |
|---|---|---|---|
| Rheem 18kW 240V | Homes needing higher flow for multiple fixtures | Up to 4.4 | Advanced self-modulation for steady hot water |
| EcoSmart ECO 11 | Compact spaces; single fixture or two at most | Up to 2.68 | 90% smaller than tank heaters |
| Rheem RTEX-24 | Whole-house upgrades; higher demand | Up to 4.0+ | Flexible 1-degree temperature control |
| Orbek 18kW | Two to three fixtures; energy savings | Up to 4.17 | Water-electricity separation for efficiency |
| WINTEMP 27kW | Medium-to-large homes; WiFi-enabled control | Up to 6.5 | Self-modulating with LED and smart features |
Below are five chosen models, each with a concise overview to assist quick decision-making. Use the “best for” notes to align with your home size, wiring capacity, and installation space.
Rheem 18kW 240V Tankless Electric Water Heater
Best for households with two to three fixtures demanding higher flow. This model uses external digital thermostatic control with an LED display and self-modulating power to meet hot water demand. It features durable copper immersion heating elements and is field serviceable. Flow rate can reach up to 4.4 GPM, making it suitable for simultaneous showers or multiple sinks. A potential limitation is higher electrical load requiring a robust 3-phase or multi-breaker setup in some homes. Choose this if you need stronger performance and adjustable precision.
Rheem 11kW 240V Tankless Electric Water Heater
Best for small homes or apartments needing reliable hot water for one or two fixtures. Features an ON/OFF dial with adjustable digital temperature display and self-modulating power control. The 11 kW model typically supports up to 2.68 GPM, which is sufficient for a single shower and a sink. Caution: ensure your electrical capacity meets the unit’s requirements, as underpowered installations can limit performance. Opt for this when space and wiring are limited, and you mainly use one hot water point at a time.
EcoSmart ECO 11 Electric Tankless Water Heater
Best for compact installations and energy efficiency. The EcoSmart ECO 11 is about 90% smaller than traditional tank heaters and can be installed on a wall or at point of use. It provides endless on-demand hot water with continuous monitoring of temperature and controlled flow. The device draws up to 54 A, and its compact dimensions (11.5 x 8 x 3.75 inches) fit tight spaces. Limitations include potential flow limitations in colder climates where higher temp rises are needed. Choose this for space savings and simplicity.
Rheem RTEX-24 24kW Tankless Water Heater
Best for whole-house upgrades with higher demand. The RTEX-24 runs on 24 kW and requires three 40-amp double-pole breakers. It supports continuous hot water for multiple fixtures, with adjustable temperature control in 1-degree increments from 80–140 degrees Fahrenheit. It’s important to verify home electrical capacity and breaker space before installation. Avoid this option if your electrical panel is already at capacity and you cannot add circuits without major upgrades.
ORBEK 18kW Tankless Water Heater Electric 240v
Best for two to three fixtures with energy savings. The 18 kW Orbek model supports up to 4.17 GPM and uses water-electricity separation to minimize scale and corrosion. It requires two 240V/40A two-pole breakers and 8 AWG wiring. A notable limitation is the need for precise electrical and water connections; plan installation carefully. Choose this if you want a balance of flow and efficiency for a mid-sized home.
WINTEMP 27kW Tankless Water Heater
Best for larger homes that require higher flow and smart controls. The WINTEMP 27kW unit offers up to 6.5 GPM and features LED temperature display, WiFi control, and self-modulating technology. Installation requires substantial electrical capacity (200 Amp service recommended) and three 40-amp breakers with heavy gauge wiring. Opt for this if you need strong whole-house performance and remote monitoring.
Buying Guide
What size tankless heater do I need? Pick a model that can handle your peak hot water demand. A single shower plus a sink needs around 2–3 GPM, while two showers may require 4–6 GPM depending on climate and fixtures. Check the unit’s GPM rating at your incoming water temperature to estimate performance.
What electrical capacity is required? Electric tankless heaters demand significant electrical service. Common setups use 3 x 40 A breakers for higher-flow models or three 40 A breakers for larger units. Confirm your panel capacity and available space in the breaker box before purchasing.
Where should I install it? Smaller homes or apartments benefit from point-of-use or wall-mounted units. For whole-house systems, plan placement near main hot water lines to reduce heat loss and improve efficiency. Ensure adequate clearance for ventilation and service access.
What about efficiency and long-term costs? Tankless heaters heat water on demand, saving energy compared with tanks. Self-modulating technology helps minimize power use by matching output to demand. Look for models with high thermal efficiency and robust temperature control to avoid overshoot or cold-water sandwich issues in cold climates.
Are there installation cautions to consider? Some models require professional electrical work and water connections. Verify local codes and consider hiring a licensed electrician or plumber for safe, compliant installation. If you rent or move soon, consider a compact unit with easier mounting and fewer wiring changes.
FAQ
- What is the typical GPM for an electric tankless heater? GPM varies by model and incoming water temperature. Most residential units range from about 2.5 to 6 GPM depending on climate and fixtures.
- Do I need a large electrical upgrade to install these? Many require dedicated breakers and robust service, often 200 Amps or more for higher-flow units. Consult an electrician before purchase.
- Can I install a tankless heater near a sink or shower? Yes, many models support point-of-use installation, especially the compact ones. Verify distance to fixtures and heat loss.
- Are these units compatible with existing plumbing? Most are compatible with standard 3/4″ NPT connections, but always verify your pipe size and fittings before buying.
- Which model is best for a two-bath home? For higher simultaneous demand, consider higher-capacity units like 24–27 kW models. If only occasional use is expected, smaller units may suffice.
- Do these require professional installation? In most cases, yes, due to electrical and plumbing considerations. Follow local codes and manufacturer guidelines.