Best 240V Electric Heaters and Tankless Water Heaters

Choosing a 240V electric heater can mean selecting a hard‑wired space heater for a garage or a high‑capacity tankless water heater for whole‑house hot water. The table below summarizes five well‑reviewed 240V models across both categories to help compare capacity, installation type, and flow rates at a glance.

Product	Type	Power/Model	Key Feature
Rheem 18kW Tankless	Tankless Water Heater	18 kW	Self‑modulation, external digital control
Rheem RTEX‑24 24kW	Tankless Water Heater	24 kW	High flow up to 5.9 GPM, digital dial
Orbek 14kW Tankless	Tankless Water Heater	14 kW	Point‑of‑use capability, LED display
EcoSmart ECO 11	Tankless Water Heater	13 kW (240V)	Self‑modulating, compact wall mount
Comfort Zone Ceiling Heater	Space Heater (Hard‑Wired)	5,000 W, 240V	Ceiling mount, fan‑forced airflow

Rheem 18kW Tankless Electric

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The Rheem 18kW 240V Tankless Electric Water Heater is designed for mid‑size usage where hot water demand varies. It features an external digital thermostatic control with LED display that reports temperature with +/-1 degree accuracy, enabling precise setpoints. The unit uses self‑modulating technology to adjust electric draw to actual hot water needs, improving energy efficiency compared with fixed‑output models.

Durability is supported by copper immersion heating elements and field‑serviceable components. Rheem rates the unit at a flow of up to 4.4 GPM, suitable for simultaneous low‑to‑moderate fixtures depending on incoming groundwater temperature. Installation requires a 240V electrical supply sized to the model’s amperage and proper plumbing connections. This model focuses on consistent temperature control and serviceability.

Rheem RTEX‑24 24kW Electric

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The Rheem RTEX‑24 24kW 240V is a higher‑capacity tankless heater intended for larger households or multiple simultaneous points of use. It includes an ON/OFF dial control with an adjustable digital temperature display, allowing straightforward local adjustments. The model uses a self‑modulating power control strategy to match element output to flow demand.

Rheem specifies a flow up to 5.9 GPM for this model, but actual output depends on inlet water temperature and desired delta‑T. Electrical supply must meet 24 kW amperage requirements, and installation often requires multi‑pole breakers and professional wiring. The RTEX‑24 aims to provide higher continuous throughput for whole‑house scenarios where multiple showers or appliances run concurrently.

Orbek 14kW On Demand

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The Orbek 14kW Tankless Electric targets small to medium point‑of‑use applications and light whole‑house needs. It includes an LED digital display and is ETL certified. Orbek notes the electrical requirements clearly: a 240V / 60 AMP two‑pole breaker with appropriate 6 AWG wiring for safe, compliant installation.

Performance is listed at up to 3.38 GPM, suitable for 2–3 fixture points depending on temperature rise. The product emphasizes water‑electricity separation to minimize scale and corrosion and claims improved efficiency through on‑demand operation. Compatibility with existing electrical capacity and plumbing layout is a primary consideration for this model.

EcoSmart ECO 11 Tankless

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The EcoSmart ECO 11 is a compact tankless heater engineered for energy efficiency and space savings. It uses patented self‑modulating technology to heat water only when needed, reducing standby energy loss. The manufacturer highlights a small wall‑mounted footprint and near‑instant temperature control with continuous monitoring within one degree of the setpoint.

This model draws substantial amperage at 240V and is commonly used at point of use or for single‑bath applications. EcoSmart promotes high thermal efficiency and minimal space requirement, making it an option where wall mounting and limited space are priorities. Flow capacity should be matched to expected fixtures and required temperature rise.

Comfort Zone Ceiling Mount Heater

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The Comfort Zone Hard‑Wired Ceiling Mount Garage Electric Space Heater is a 5,000W fan‑forced unit intended for garages, workshops, and other utility spaces. The ceiling‑mount design frees floor space and allows targeted directional heating via adjustable louvers and mounting angle.

Built from heavy‑gauge steel, the unit is optimized for durable, overhead installations and includes overheat protection and thermal cut‑out switches. As a 240V hard‑wired heater, it requires appropriate circuit wiring and is ETL compliant for safety. This model is appropriate for spaces where rapid, distributed forced‑air heating is preferred over radiant or portable solutions.

Buying Guide

Selecting a 240V electric heater requires matching the device type, capacity, and installation needs to your home or workspace. Below are key considerations and comparison perspectives to guide a purchase.

1. Identify Heater Type And Intended Use

• Tankless Water Heaters (On‑demand): Best when continuous hot water is required without storage tanks. Consider flow rate (GPM) and temperature rise.
• Hard‑Wired Space Heaters (Ceiling or Wall): Designed for heating air in garages, workshops, or industrial spaces. Evaluate mounting, airflow method (fan‑forced vs. radiant), and coverage area.

2. Power Rating And Electrical Supply

• 240V devices vary widely in kW or wattage and corresponding amperage. Higher kW yields higher potential heat or flow but demands larger breakers and thicker wiring.
• Confirm existing panel capacity and whether new circuits are needed. Professional electrical assessment is recommended for multi‑kW installations.

3. Flow Rate And Temperature Rise (For Tankless)

• Flow Rate (GPM): Indicates maximum simultaneous delivery. Match to number of fixtures and usage patterns.
• Temperature Rise: Difference between incoming groundwater temperature and desired output. Northern climates need higher kW to sustain GPM at higher delta‑T.

4. Installation Constraints And Placement

• Tankless units: wall‑mounted space, ventilation (if required by model), and plumbing layout. Accessibility for servicing matters for models with field‑serviceable elements.
• Space heaters: ceiling vs. wall mount affects heat distribution; overhead mounting often suits workshops and garages; consider clearance and mounting structure.

5. Controls, Safety, And Certifications

• Controls: digital thermostats, LED displays, and dial controls provide varying precision. External thermostatic controllers can simplify adjustments.
• Safety: look for thermal cut‑outs, overheat protection, and certifications such as ETL or CSA for electrical safety compliance.

6. Efficiency And Operational Costs

• Self‑modulating technology adjusts power to demand and can reduce energy use compared with fixed‑output heaters.
• For water heaters, compare electrical draw and claimed thermal efficiency; on‑demand units avoid standby losses of tank systems.

7. Maintenance And Serviceability

• Consider accessibility to heating elements, scale management strategies, and whether replacement parts are user‑serviceable.
• Hard‑wired space heaters may require periodic dusting and verification of thermal sensors; tankless units may require descaling in hard‑water areas.

8. Sizing Examples And Comparative Perspectives

• Small Point‑Of‑Use: Models in the 8–14 kW range suit single sinks or low demand showers when groundwater temperature is moderate.
• Medium Household Use: 18 kW units serve moderate simultaneous demand; balance GPM needs with local inlet temperatures.
• Whole‑House Or Multiple Fixtures: 24 kW and higher provide the throughput for several fixtures at once, but require substantial electrical infrastructure.
• Workshop Heating: A 5,000W ceiling‑mounted fan‑forced heater offers targeted space heating and requires proper hard‑wiring and clearances.

9. Professional Installation And Permits

• High‑kW 240V installations typically require licensed electricians and possibly building permits. Verify local code requirements for electrical and plumbing work.
• For water heaters, ensure water pressure, pipe sizing, and venting (if applicable) meet manufacturer instructions.

10. Final Comparison Checklist

• Match kW to expected load and inlet water temperature (for tankless).
• Confirm circuit breaker size and wiring gauge compatibility.
• Evaluate control precision (digital vs. analog) and ease of use.
• Check safety features and third‑party certifications.
• Estimate maintenance needs and serviceability in your water quality conditions.