Rheem vs Noritz: Tankless Water Heaters Compared by Specs
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When you compare a rheem vs noritz tankless water heater, you are looking at two distinct approaches to hot water delivery. Both brands offer reliable, compact units designed for residential use. The main difference lies in their power source and capacity. Rheem provides a compact electric option, while Noritz offers a high-output natural gas model. This guide breaks down their specifications to help you decide which fits your home.
Key differences
| Aspect | Rheem 18kW 240V Electric Tankless Water Heater | Noritz EZ Series Pro 11.1 GPM Natural Gas Heater |
|---|---|---|
| Fuel Type | Electric | Natural Gas |
| Flow Rate | 4.4 GPM | 11.1 GPM |
| Voltage | 240 V | 120 V |
| BTU | not listed | 199,900 BTU |
| Dimensions | 3.5 x 14.5 x 18.5 inches | 11.8 x 18.1 x 26.1 inches |
| Installation Location | not listed | Indoor/Outdoor |
Which one should you choose?
Choose Rheem 18kW 240V Electric Tankless Water Heater if
- You need a compact unit for point-of-use or small whole-home applications.
- You prefer electric heating with precise digital temperature control.
- You have limited space and need a lightweight, wall-mounted device.
Choose Noritz EZ Series Pro 11.1 GPM Natural Gas Heater if
- You require high flow rates for multiple simultaneous showers.
- You have natural gas access and need a powerful residential heater.
- You want a unit suitable for both indoor and outdoor installation.
Verdict: Choose the Rheem model if your priority is compact size, electric efficiency, and precise temperature control for smaller demands. Select the Noritz unit if you need high-volume hot water for a large household and have natural gas available. Your choice depends entirely on your fuel source and hot water volume needs.
Rheem vs Noritz Spec Breakdown
Flow rate capacity
Flow rate determines how many fixtures can run simultaneously. The Rheem 18kW unit delivers up to 4.4 GPM. This is sufficient for a single bathroom or a kitchen sink. The Noritz EZ Series Pro offers a much higher 11.1 GPM. This capacity supports multiple bathrooms and appliances at once. If you need hot water for a large household, the Noritz provides significantly more volume. The Rheem is better suited for smaller, point-of-use applications or single-bath setups.
Fuel type efficiency
The power source changes your installation needs and operating costs. The Rheem is an electric model requiring 240V power. It uses copper immersion heating elements. The Noritz burns natural gas with 199,900 BTU input. Gas heaters generally heat water faster and handle higher demands than electric units. You need a gas line for the Noritz. You need a dedicated electrical circuit for the Rheem. Choose the fuel source available at your home.
Physical dimensions
Space constraints often dictate which unit fits your home. The Rheem is very compact, measuring 3.5 by 14.5 by 18.5 inches. It weighs only 14.8 pounds. The Noritz is larger, measuring 11.8 by 18.1 by 26.1 inches. It weighs 77.2 pounds. The Rheem fits easily in tight closets or under sinks. The Noritz requires more wall space and structural support. If you have limited room, the Rheem is the clear winner for space saving.
Temperature control precision
Consistent water temperature improves comfort. The Rheem features an external digital thermostatic control with an LED display. It offers plus or minus 1 degree Fahrenheit accuracy. This allows you to set the exact temperature you want. The Noritz data does not specify the temperature control precision. It focuses on high output capacity. If precise temperature settings are a priority for your daily routine, the Rheem provides better control visibility.
Installation location
Where you place the unit affects ventilation and piping. The Rheem is designed for indoor use with bottom water connections. The Noritz is built for both indoor and outdoor installation. This flexibility allows the Noritz to be placed on an exterior wall, saving interior space. You do not need to run long pipes through your home. If you want to install the heater outside to free up interior closet space, the Noritz is the better choice.
Which tankless water heater fits you
Small household with low hot water needs
You need a compact unit for limited spaces. The Rheem model measures just 3.5 by 14.5 by 18.5 inches. It weighs only 14.8 pounds. The 4.4 GPM flow rate suits single fixtures. Its 18 kW electric power is ideal for small homes. You get precise temperature control with ±1°F accuracy. This unit fits easily into tight utility areas.
Large family needing high volume hot water
You require significant hot water for multiple bathrooms. The Noritz unit delivers 11.1 GPM. This high flow rate supports simultaneous use of several fixtures. It generates 199,900 BTU of heating power. The natural gas fuel type ensures consistent performance. You get reliable heat for whole-house demands. This model handles high usage without dropping temperature.
User wanting precise digital temperature management
You value exact temperature settings for comfort. The Rheem heater features an external digital thermostat. It offers LED display with ±1°F accuracy. You can adjust power to match demand. The self-modulation technology ensures stable output. You see real-time temperature changes on the display. This precision helps maintain consistent water heat levels.
Installer seeking flexible placement options
You need a unit for indoor or outdoor use. The Noritz model supports both installation locations. It is built for performance in various environments. The natural gas connection allows for flexible routing. You can place it in utility rooms or outside. This versatility simplifies installation planning. You do not need to restrict placement to specific areas.
The products compared
Rheem 18kW 240V Electric Tankless Water Heater
Best for: compact electric whole-house heating
- Fuel Type
- Electric
- Flow Rate
- 4.4 GPM
- Wattage
- 18 kW
- Voltage
- 240 V
- Temperature Control
- ±1°F
- Dimensions
- 3.5 x 14.5 x 18.5 inches
View on Amazon: Rheem 18kW 240V Electric Tankless Water Heater Affiliate link
This Rheem unit delivers 18 kW of power at 240 volts. It provides a flow rate of up to 4.4 GPM for whole-house use. The device features external digital thermostatic control with ±1°F accuracy. Its compact dimensions of 3.5 x 14.5 x 18.5 inches allow for flexible installation. You get durable copper immersion heating elements that are field serviceable. This model suits homes needing reliable electric heating without gas lines.
Pros
- 18 kW output for whole-house demand
- ±1°F temperature accuracy
- Compact 3.5-inch depth
- Field-serviceable copper elements
Cons
- Electric fuel type limits placement to wired locations
- 4.4 GPM may struggle with simultaneous high-demand uses
- Requires 240V electrical circuit
Good fit if
- You need a compact unit for tight spaces
- You require precise temperature control
- You want field-serviceable components
Skip if
- You need gas-powered heating
- You require flow rates above 5 GPM
- You lack a 240V electrical supply
Verdict: Rheem 18kW Electric Tankless Heater fits homes needing compact, precise electric heating. It suits users prioritizing temperature accuracy and serviceability over raw gas power.
Noritz EZ Series Pro 11.1 GPM Natural Gas Heater
Best for: high-flow residential natural gas needs
- Fuel Type
- Natural Gas
- Flow Rate
- 11.1 GPM
- BTU
- 199,900 BTU
- Installation Location
- Indoor/Outdoor
- Voltage
- 120 V
- Dimensions
- 11.8 x 18.1 x 26.1 in
View on Amazon: Noritz EZ Series Pro 11.1 GPM Natural Gas Heater Affiliate link
This Noritz unit delivers 11.1 gallons per minute using 199,900 BTUs of natural gas power. It operates on a 120-volt circuit and measures 11.8 by 18.1 by 26.1 inches. The silver casing weighs 77.2 pounds and supports both indoor and outdoor installation. You get reliable performance in a compact footprint suitable for residential use.
Pros
- 11.1 GPM flow rate
- 199,900 BTU heating capacity
- Indoor and outdoor installation options
- Compact 11.8-inch depth
Cons
- Requires 120-volt electrical connection
- Heavier at 77.2 pounds
- Natural gas fuel type only
Good fit if
- You need high flow rates for multiple fixtures
- You have natural gas available
- You want indoor or outdoor flexibility
Skip if
- You only have 240-volt electrical outlets
- You prefer electric heating systems
- You need a smaller footprint than 11.8 inches deep
Verdict: Noritz GQ-C3261WX 11.1 GPM Gas Heater suits homes needing strong hot water output with flexible placement. It fits users with natural gas lines who value high capacity over electric simplicity.
Specifications side by side
| Spec | Rheem 18kW 240V Electric Tankless Water Heater | Noritz EZ Series Pro 11.1 GPM Natural Gas Heater |
|---|---|---|
| Fuel Type | Electric | Natural Gas |
| Flow Rate | 4.4 GPM | 11.1 GPM |
| BTU | not stated | 199,900 BTU |
| Wattage | 18 kW | not stated |
| Installation Location | not stated | Indoor/Outdoor |
| Voltage | 240 V | 120 V |
| Temperature Control | ±1°F | not stated |
| Dimensions | 3.5 x 14.5 x 18.5 inches | 11.8 x 18.1 x 26.1 in |
| Use | Whole House | not stated |
| Weight | 14.8 pounds | 77.2 pounds |
| Size | Small | not stated |
| Color | Gray | Silver |
| Model | RTEX-18 | GQ-C3261WX-FF US NG |
Frequently asked questions
Which tankless water heater is better for a small apartment?
The Rheem 18kW Electric Tankless Water Heater is the better choice for small spaces. It measures only 3.5 by 14.5 by 18.5 inches and weighs 14.8 pounds. This compact size fits easily into tight utility areas. The Noritz unit is significantly larger and heavier, making it less suitable for limited square footage.
Do I need natural gas for the Noritz heater?
Yes, the Noritz EZ Series Pro requires a natural gas connection. It is designed specifically for natural gas fuel type. You cannot use propane or electricity with this model. If your home lacks a natural gas line, you will need to choose an electric alternative like the Rheem unit instead.
Can I install the Noritz heater outdoors?
Yes, the Noritz EZ Series Pro is designed for outdoor installation. Its construction allows it to withstand outdoor conditions. The Rheem electric unit is typically installed indoors due to its electrical components. Choose the Noritz if you have an exterior wall with a gas line available.
How wide is the Rheem electric tankless heater?
The Rheem 18kW unit is 14.5 inches wide. It is also 18.5 inches long and 3.5 inches deep. This slim profile makes it easy to mount on a wall. The Noritz model is wider at 18.1 inches and deeper, requiring more horizontal space for installation.
Which unit is lighter and easier to handle?
The Rheem 18kW Electric Tankless Water Heater is much lighter. It weighs only 14.8 pounds. The Noritz EZ Series Pro weighs 77.2 pounds. The Rheem unit is easier for one person to lift and mount. The Noritz requires more effort or assistance during installation due to its weight.
Is the Rheem heater suitable for whole-house use?
Yes, the Rheem 18kW unit is rated for whole-house use. It provides electric heating for residential needs. However, its flow rate is lower than gas models. It works best for homes with modest hot water demands or single-bathroom setups. The Noritz offers higher flow for larger households.