Rheem 11kW 240V Tankless Electric Water Heater Review: Compact Power for Reliable On-Demand Hot Water
Modern homes increasingly demand efficient, space-saving solutions that deliver comfort without unnecessary energy waste. Traditional tank water heaters, while familiar, often struggle with limited hot water supply, standby heat loss, and bulky installation requirements. Electric tankless water heaters address these challenges by heating water only when it is needed, providing consistent performance in a compact form factor.
The Rheem 11kW 240V Tankless Electric Water Heater is designed to meet the needs of small households, apartments, condos, and point-of-use applications. With self-modulating power control, an adjustable digital temperature display, and a flow rate of up to 2.68 gallons per minute, this model offers dependable hot water without the space and energy demands of a storage tank.
This comprehensive review explores the design, performance, efficiency, installation considerations, and ideal use cases of the Rheem 11kW tankless electric water heater, helping you decide whether it is the right solution for your hot water needs.
Overview of the Rheem 11kW Tankless Electric Water Heater
The Rheem 11kW Tankless Electric Water Heater is an on-demand system that heats water instantly as it flows through the unit. Powered by a 240V electrical connection, it eliminates the need for a storage tank and provides continuous hot water within its rated capacity.
Its compact dimensions, intuitive controls, and advanced self-modulating technology make it especially suitable for homes where space is limited and hot water demand is moderate. Whether used as a primary water heater in a small residence or as a supplemental unit for a specific fixture, this model is engineered for efficiency and reliability.
Key Features and Benefits
- 11kW electric tankless performance
- 240V power for fast water heating
- Up to 2.68 GPM flow rate
- Self-modulating power control
- ON/OFF dial control with digital temperature display
- Side-mounted 1/2-inch NPT water connections
- Compact, wall-mounted design
- Continuous on-demand hot water
These features combine to deliver a balance of performance, efficiency, and convenience, making the unit a practical choice for targeted hot water applications.
Product Specifications Table
| Feature | Specification |
|---|---|
| Brand | Rheem |
| Product Type | Tankless Electric Water Heater |
| Power Rating | 11 kW |
| Voltage | 240V |
| Power Source | AC |
| Maximum Flow Rate | Up to 2.68 GPM |
| Capacity | 2.68 gallons (flow-based) |
| Product Dimensions | 8.25 inches W x 12.63 inches H |
| Temperature Control | Adjustable digital display |
| Control Type | ON/OFF dial control |
| Power Modulation | Self-modulating |
| Water Connections | Side-mounted 1/2-inch NPT |
| Special Feature | LED display |
| Installation Type | Wall-mounted |
How Tankless Electric Water Heating Works
Tankless electric water heaters operate by heating water instantly as it passes through internal heating elements. When a hot water tap is opened, cold water enters the unit, where electric elements rapidly raise the temperature before delivering it to the fixture.
Unlike traditional tank heaters that continuously heat stored water, the Rheem 11kW Tankless Electric Water Heater only consumes energy when hot water is needed. This approach eliminates standby heat loss and ensures a more efficient use of electricity.
Hot Water Performance and Flow Rate
With a maximum flow rate of up to 2.68 GPM, the Rheem 11kW model is well-suited for light to moderate hot water demand. Its performance is ideal for:
- One shower at a time
- A bathroom sink and shower used separately
- Kitchen sink or utility sink applications
The actual flow rate depends on incoming water temperature and desired output temperature. In warmer climates, the unit can achieve higher flow rates, while colder incoming water may slightly reduce performance.
Self-Modulating Power Control Explained
One of the most important features of this unit is its self-modulating power control. Instead of operating at full power all the time, the system automatically adjusts energy usage based on water flow and temperature demand.
Advantages of Self-Modulating Technology
- Reduces unnecessary electricity consumption
- Improves temperature stability
- Extends the life of heating elements
- Enhances overall efficiency
By delivering only the power required at any given moment, the Rheem 11kW water heater helps balance performance with energy savings.
Digital Temperature Display and ON/OFF Dial Control
The heater features an easy-to-use ON/OFF dial control paired with a clear digital temperature display. This allows users to adjust and monitor water temperature with precision.
User Control Benefits
- Quick temperature adjustments
- Clear visibility of current settings
- Simple operation without complex menus
This straightforward interface makes the unit accessible for users of all experience levels.
Compact Design and Space Efficiency
Measuring just 8.25 inches wide and 12.63 inches high, the Rheem 11kW tankless water heater is extremely compact. Its slim profile allows it to fit into tight spaces where traditional tank heaters cannot.
Ideal Installation Locations
- Under sinks
- Utility closets
- Garages
- Laundry rooms
- Small mechanical spaces
The compact size also simplifies installation and makes it an excellent choice for retrofitting older homes or upgrading point-of-use systems.
Side-Mounted Water Connections
The unit features side-mounted 1/2-inch NPT water connections, which help streamline plumbing installation. This configuration is especially helpful in confined spaces, allowing for clean and efficient routing of water lines.
Standard connection sizing also ensures compatibility with most residential plumbing systems, reducing the need for adapters or modifications.
Energy Efficiency and Cost Considerations
Energy efficiency is a primary reason homeowners choose tankless electric water heaters. The Rheem 11kW model is designed to minimize energy waste by heating water only when needed and adjusting power usage dynamically.
Efficiency Benefits
- No standby heat loss
- Power usage matches demand
- Reduced electricity consumption during low usage
- Lower operating costs compared to tank heaters
While actual savings depend on usage patterns and electricity rates, many users experience noticeable reductions in energy consumption.
Climate and Incoming Water Temperature Impact
The performance of electric tankless water heaters is influenced by incoming water temperature. The Rheem 11kW unit performs best in moderate to warm climates where groundwater temperatures are higher.
Climate Performance Overview
| Climate Type | Expected Performance |
|---|---|
| Warm Climate | Excellent |
| Moderate Climate | Very Good |
| Cold Climate | Reduced flow rate |
In colder regions, households may need to limit simultaneous hot water use or consider a higher-kilowatt model.
Electrical Requirements and Installation Notes
The Rheem 11kW Tankless Electric Water Heater operates on 240 volts, which requires a dedicated electrical circuit. Proper installation is critical to ensure safe and reliable operation.
Key Electrical Considerations
- Dedicated 240V circuit
- Correct breaker size
- Proper wire gauge
- Compliance with local electrical codes
Due to these requirements, professional installation is often recommended, especially for users unfamiliar with high-voltage electrical work.
Safety and Reliability Features
Rheem incorporates multiple safety measures into its tankless electric water heaters to protect both the appliance and the user.
Safety Highlights
- Overheat protection
- Digital temperature regulation
- Stable power modulation
- Durable internal components
These features help ensure consistent performance and reduce the risk of damage caused by overheating or electrical issues.
Maintenance and Long-Term Use
One advantage of electric tankless water heaters is their relatively low maintenance requirements. The Rheem 11kW model does not require tank flushing, but periodic inspection is recommended.
Basic Maintenance Tips
- Inspect electrical connections periodically
- Check water connections for leaks
- Descale the unit in areas with hard water
With proper care, the unit is designed to deliver reliable performance over many years.
Comparison With Traditional Tank Water Heaters
| Feature | Rheem 11kW Tankless | Traditional Tank Heater |
|---|---|---|
| Hot Water Supply | Continuous (within capacity) | Limited by tank size |
| Energy Efficiency | High | Moderate |
| Standby Heat Loss | None | Yes |
| Space Requirement | Very compact | Large |
| Recovery Time | Instant | Long |
The tankless design clearly excels in efficiency and space savings, particularly for small households.
Comparison With Higher-Power Tankless Models
The Rheem 11kW model is designed for moderate demand. Higher-kilowatt models are available for larger households or colder climates.
| Feature | 11kW Model | Higher kW Models |
|---|---|---|
| Power Output | 11 kW | 18–36 kW |
| Max Flow Rate | 2.68 GPM | Higher |
| Electrical Demand | Moderate | High |
| Best Use | Small homes, point-of-use | Whole-house |
Selecting the correct size is essential for achieving optimal performance.
Ideal Use Cases
The Rheem 11kW 240V Tankless Electric Water Heater is best suited for:
- Apartments and condos
- Small homes with one bathroom
- Point-of-use applications
- Guest houses or additions
- Households with moderate hot water demand
It may not be ideal for large families with multiple simultaneous hot water needs.
Rheem Brand Reliability
Rheem is a well-established brand in the water heating industry, known for producing durable and efficient products. The company’s experience and commitment to quality are reflected in the design and performance of the 11kW tankless model.
Users benefit from Rheem’s reputation for reliability, consistent manufacturing standards, and ongoing product support.
Final Assessment
The Rheem 11kW Tankless Electric Water Heater offers a practical and efficient solution for homeowners seeking compact, on-demand hot water. Its self-modulating power control, intuitive digital display, and space-saving design make it an excellent choice for small households and point-of-use installations.
While it is not intended for high-demand, multi-bathroom homes, it excels in applications where efficiency, simplicity, and reliability are priorities. For users looking to replace a traditional tank heater or add a dedicated hot water source without sacrificing space, this Rheem model delivers dependable performance and modern convenience.