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The Rheem 13kW Compact Electric Tankless Water Heater delivers precise temperature control and a small footprint for tight installations. If you are searching for rheem 13kw compact electric tankless alternatives, you likely need different flow rates or features. This model provides up to 3.17 GPM at 240V. Its compact dimensions make it easy to mount in small spaces. However, you might need more hot water for multiple fixtures or want smart home connectivity.
This list includes 6 similar picks that overlap with the original specifications. Each alternative shares key traits like 240V operation and tankless design. Some options offer higher wattage for greater flow capacity. Others include WiFi control for remote management. You can compare their size, power, and intended use to find the best fit. The selections cover whole-house needs and point-of-use applications. This guide helps you choose based on your specific electrical capacity and hot water demands.
01 How alternatives compare to Rheem
Thermomate 18kW Electric Tankless Water Heater
The Thermomate 18kW model offers 5kW more heating power than the Rheem unit. This increase supports higher flow rates for homes with an 80A electrical capacity. You get precise temperature settings in a slightly larger frame measuring 13.1 by 17.1 inches. The Rheem is more compact at 12.6 inches long but limited to 13kW. Choose the Thermomate if you need more hot water volume and have the electrical infrastructure to support the higher draw.
Westinghouse 14 kW Smart Wi-Fi Tankless Water Heater
The Westinghouse 14kW unit adds smart Wi-Fi connectivity to a 240V system. It matches the Rheem in compact form factor but provides 1kW more power. The dimensions are 9.56 by 12.6 inches, which is similar to the Rheem’s 12.6-inch length. This model suits users who want remote control features for point-of-use applications. The Rheem lacks digital connectivity and relies on local controls. Pick the Westinghouse if smart home integration is a priority for your installation.
Orbek 18kW 240V Tankless Electric Water Heater
The Orbek 18kW heater delivers significantly more power than the 13kW Rheem. It supports up to 4.22 GPM flow, which is higher than the Rheem’s 3.17 GPM limit. The unit is compact at 8 by 11 inches and features an ETL certification. It requires dual breakers due to the higher amperage. Choose the Orbek if you need whole-house coverage and have the electrical space. The Rheem is better for smaller loads where 13kW is sufficient.
WINTEMP 18 kW Tankless Water Heater with WiFi
The WINTEMP 18kW model provides 4.3 GPM output with built-in WiFi management. It offers 5kW more capacity than the Rheem 13kW unit. The dimensions are 11.1 by 19.1 inches, making it longer than the Rheem’s 12.6-inch profile. This unit is designed for whole-house hot water needs. The Rheem is more compact and better for tight spaces. Select the WINTEMP if you require strong flow rates and want the convenience of remote temperature adjustments via an app.
SIVUATEK 18kW Electric Tankless Water Heater
The SIVUATEK 18kW heater provides steady hot water for three to four fixtures. It delivers 5kW more power than the Rheem 13kW model. The unit measures 12.2 by 17.3 inches, which is taller than the Rheem. It focuses on high efficiency and precise temperature control without adding smart features. Choose this model if you need reliable whole-house supply and do not require WiFi connectivity. The Rheem is a better fit for smaller, low-demand installations.
WINTEMP 18kW Electric Tankless Water Heater
The WINTEMP 18kW LED model offers clear digital feedback and ETL safety certification. It provides 5kW more heating capacity than the Rheem 13kW unit. The dimensions are 9.7 by 14 inches, which is comparable in width but taller than the Rheem. This unit is ideal for homes needing stable hot water for two to three points of use. The Rheem lacks the same level of visual feedback. Pick this WINTEMP version if you value clear status indicators and higher power output.
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | Rheem 13kW Compact Electric Tankless Water Heater Best overall | compact installations with moderate hot water needs | |
| 2 | Thermomate 18kW Electric Tankless Water Heater Best premium | homes with 80A electrical capacity | |
| 3 | Westinghouse 14 kW Smart Wi-Fi Tankless Water Heater Best 14 kw | Smart home integration and compact installation | |
| 4 | Orbek 18kW 240V Tankless Electric Water Heater Best budget | Whole-house electric heating with compact wall-mount design | |
| 5 | WINTEMP 18 kW Tankless Water Heater with WiFi Also great | Whole house hot water with WiFi control | |
| 6 | SIVUATEK 18kW Electric Tankless Water Heater Also great | high-efficiency whole-house hot water supply | |
| 7 | WINTEMP 18kW Electric Tankless Water Heater Best led display | homes needing LED feedback and ETL safety |
Rheem 13kW Compact Electric Tankless Water Heater
Best for: compact installations with moderate hot water needs
- Max Flow Rate
- up to 3.17 GPM
- Heating Capacity
- 13kW
- Voltage
- 240V
- Features
- Tankless
- Dimensions
- 12.6 × 8.25 × 3.63 inches
- Weight
- 3.97 pounds
The Rheem RTEX-13 is a 13kW, 240V tankless water heater designed for compact installations. It delivers up to 3.17 GPM with 99.8% energy efficiency. The unit features external adjustable digital thermostatic control with LED display and copper immersion heating elements. Its small footprint makes it suitable for tight spaces. You get precise temperature adjustments in 1-degree increments. This model is a solid choice for point-of-use or small household needs.
- 13kW heating capacity with 240V power
- Compact dimensions: 12.6 x 8.25 x 3.63 inches
- 99.8% energy efficiency rating
- External adjustable digital thermostatic control with LED display
- Durable copper immersion two heating elements
- Lower flow rate of up to 3.17 GPM compared to 18kW competitors reaching 4.22+ GPM
- Lower power output of 13kW versus the 18kW standard on other list items
- Heavier build at 3.97 pounds compared to lighter alternatives
- You need a compact unit for tight spaces
- You want precise temperature control with 1-degree increments
- You have a 240V electrical supply
- You require whole-house hot water for multiple simultaneous uses
- You need higher flow rates above 3.5 GPM
- You prefer WiFi connectivity for remote control
Verdict: Rheem 13kW Compact Electric Tankless is a compact, efficient option for low-to-medium demand. It suits users prioritizing precise temperature control and small footprint over high flow rates.
Thermomate 18kW Electric Tankless Water Heater
Best for: homes with 80A electrical capacity
- Fuel Type
- Electric
- Max Flow Rate
- Up to 4.4GMP
- Heating Capacity
- 18kW
- Installation Location
- Indoor
- Voltage
- 240 Volt
- Temperature Range
- 80°F to 140°F
The ThermoMate ET180 is a 18kW electric tankless water heater designed for indoor use. It delivers up to 4.4 GPM at 240V, heating water in three seconds. The unit features a digital display with 1°F increments from 80°F to 140°F. Its compact gray housing measures 17.1 inches high by 13.1 inches wide. This model suits households needing on-demand hot water with precise temperature control.
- 18kW heating capacity for high flow rates
- Digital display allows 1°F temperature adjustments
- ETL certified for safety and leakage protection
- Self-modulating technology optimizes energy use
- Requires two double-pole 40A breakers, totaling 80A
- Uses 8AWG wire gauge for installation
- Maximum flow rate is lower than 4.3 GPM competitors
- You need a compact unit for tight indoor spaces
- You want precise temperature control in 1°F increments
- You have the electrical capacity for an 80A circuit
- You only have a single 40A breaker available
- You require a flow rate exceeding 4.4 GPM
- You need an outdoor-rated installation
Verdict: ThermoMate 18kW Electric Tankless Water Heater offers reliable performance for homes with adequate electrical infrastructure. It fits buyers who prioritize precise temperature settings and compact dimensions over maximum flow capacity.
Westinghouse 14 kW Smart Wi-Fi Tankless Water Heater
Best for: Smart home integration and compact installation
- Fuel Type
- Electric
- Max Flow Rate
- 3.4 GPM
- Heating Capacity
- 14kW
- Voltage
- 240V
- Fixture Capacity
- 2 Point of Use
- Temperature Range
- 86-140℉
The Westinghouse 14kW unit offers 3.4 GPM flow at 240V, supporting two simultaneous points of use. Its compact 12.6-inch height saves space while smart WiFi controls allow remote adjustments. This model suits households needing reliable instant hot water with modern connectivity features for daily convenience.
- 14kW heating capacity delivers up to 3.4 GPM
- Supports 2 simultaneous points of use
- Compact design measures 12.6 inches in height
- WiFi connectivity with voice control support
- ETL certified with 4-layer safety protection
- Lower flow rate of 3.4 GPM compared to 4.22 GPM on competing 18kW models
- Requires a dedicated 60A double-pole breaker for installation
- Limited temperature range of 86-140°F compared to broader ranges
- You need a compact unit for tight spaces
- You want smart home integration via WiFi
- You require reliable performance for two fixtures
- You need higher flow rates for whole-house use
- You cannot install a 60A circuit
- You prefer simpler non-smart controls
Verdict: Westinghouse 14kW Electric Tankless Water Heater fits users who value smart connectivity and compact sizing over maximum flow rates. It provides steady hot water for two points of use in modern homes.
Orbek 18kW 240V Tankless Electric Water Heater
Best for: Whole-house electric heating with compact wall-mount design
- Fuel Type
- Electric
- Max Flow Rate
- 4.22 GPM
- Heating Capacity
- 18 kW
- Voltage
- 240 V
- Fixture Capacity
- 2-3 Point of Use
- Installation Type
- Whole House
This Orbek M-18 unit delivers 18 kW of heating power at 240V. It provides a maximum flow rate of 4.22 GPM, making it suitable for whole-house use. The compact design measures 11 inches in height and 8 inches in width. It features ETL certification for safety. You get instant hot water with modulation technology to reduce standby loss. This model fits homes needing reliable on-demand heating without a bulky tank.
- 18 kW heating capacity for strong performance
- 4.22 GPM max flow rate supports multiple fixtures
- Compact 11-inch height saves wall space
- ETL certified for safety compliance
- Wall-mounted installation with standard 3/4 NPT connections
- Lower flow rate of 4.22 GPM compared to 4.3 GPM on other 18kW models in this list
- Requires 2 x 40 Amp DP breakers, which is a higher electrical demand than standard single-breaker units
- You need an 18kW unit for whole-house hot water supply
- You have the electrical capacity for two 40-amp double-pole breakers
- You want a compact unit that mounts easily to a wall
- You require a flow rate higher than 4.22 GPM
- You cannot install dual 40-amp breakers in your electrical panel
- You prefer a single-breaker installation for simplicity
Verdict: Orbek M-18 18kW Electric Tankless Water Heater offers solid 18kW power and 4.22 GPM flow for whole-house needs. It suits buyers who have the electrical space for dual breakers and want a compact, ETL-certified solution.
WINTEMP 18 kW Tankless Water Heater with WiFi
Best for: Whole house hot water with WiFi control
- Fuel Type
- Electric
- Max Flow Rate
- 4.3 GPM
- Heating Capacity
- 18kW
- Voltage
- 240V
- Installation Type
- Whole House
- Features
- Tankless
This WINTEMP WN18 unit delivers 18 kW of heating power at 240 volts, producing up to 4.3 GPM. It features WiFi control and measures 11.1 by 19.1 by 4 inches. You get stable temperature adjustment and ETL certification for safety. The compact design saves space while providing continuous hot water for residential use.
- 18 kW heating capacity for strong output
- Up to 4.3 GPM maximum flow rate
- WiFi remote temperature adjustment
- ETL certified for safety compliance
- Compact 4-inch depth for wall mounting
- Requires 75 Amps total circuit capacity
- Heavier 12-pound build than some rivals
- Limited to 240V electrical systems only
- You need a compact unit for tight spaces
- You want remote WiFi temperature control
- You have a 240V electrical supply ready
- You require a 120V installation option
- You cannot support a 75 Amp electrical load
- You prefer a unit under 10 pounds
Verdict: WINTEMP 18kW Electric Tankless Heater offers reliable 4.3 GPM output with convenient WiFi management. It fits homes needing strong flow in a small footprint, provided your electrical panel supports the high amperage draw.
SIVUATEK 18kW Electric Tankless Water Heater
Best for: high-efficiency whole-house hot water supply
- Fuel Type
- Electric
- Heating Capacity
- 18kW
- Voltage
- 240V
- Fixture Capacity
- 3–4 simultaneous usage points
- Temperature Range
- 86°F to 131°F
- Installation Type
- Whole House
This SIVUATEk unit delivers 18kW of heating power at 240V. It supports 3–4 simultaneous usage points with 99.8% thermal efficiency. The LED display allows precise temperature settings from 86°F to 131°F. Its compact gray design fits under-sink or on-wall installations. You get endless hot water with advanced safety features like leakage protection. This model suits whole-house needs where space is limited.
- 18kW heating capacity for strong hot water output
- 99.8% thermal efficiency reduces standby energy loss
- LED display with 1°F increment temperature control
- Compact dimensions of 15.87 x 11.14 x 2.87 inches
- ETL certified with leakage and overheating protection
- Requires two 40-amp circuit breakers for operation
- Physical dimensions are bulkier than some competitors
- Temperature range maxes out at 131°F
- You need 18kW power for 3–4 simultaneous fixtures
- You want precise temperature control via LED display
- You have space for a 15.87-inch tall unit
- Your electrical panel cannot support two 40-amp breakers
- You require a more compact unit than 15.87 inches tall
- You need a model with WiFi connectivity
Verdict: SIVUATEK 18kW Electric Tankless Water Heater provides steady hot water for 3–4 fixtures. It fits homes needing high efficiency and precise temperature control without WiFi features.
WINTEMP 18kW Electric Tankless Water Heater
Best for: homes needing LED feedback and ETL safety
- Fuel Type
- Electric
- Max Flow Rate
- 4.3 GPM
- Heating Capacity
- 18kW
- Voltage
- 240V
- Fixture Capacity
- 2-3 points of use
- Features
- Tankless, LED Display
The WINTEMP 18kW unit delivers up to 4.3 GPM of hot water at 240V. It features an LED display and self-regulating technology to save energy. This compact, wall-mounted heater fits 2-3 points of use. It includes ETL certification and multiple safety protections. You get endless hot water without preheating delays. The gray unit weighs 12 pounds and measures 14 inches high.
- 18kW heating capacity for strong performance
- Up to 4.3 GPM flow rate
- LED display for clear status viewing
- Self-regulating energy-saving technology
- ETL certified for safety
- Lower flow rate than 18kW competitors offering 4.22 GPM
- Requires 75A total amperage with two 40A breakers
- Heavier build at 12 pounds compared to lighter alternatives
- You need an LED display for easy monitoring
- You want ETL certification for safety assurance
- You require a compact wall-mounted design
- You need more than 4.3 GPM flow
- You cannot install dual 40A breakers
- You prefer a lighter unit under 12 pounds
Verdict: WINTEMP 18kW Electric Tankless Water Heater suits buyers who value clear LED feedback and ETL safety certification. It fits homes needing 2-3 points of use with stable hot water delivery.
02 Specifications side by side
| Spec | Rheem 13kW Compact Electric Tankless Water Heater | Thermomate 18kW Electric Tankless Water Heater | Westinghouse 14 kW Smart Wi-Fi Tankless Water Heater | Orbek 18kW 240V Tankless Electric Water Heater | WINTEMP 18 kW Tankless Water Heater with WiFi | SIVUATEK 18kW Electric Tankless Water Heater | WINTEMP 18kW Electric Tankless Water Heater |
|---|---|---|---|---|---|---|---|
| Fuel Type | – | Electric | Electric | Electric | Electric | Electric | Electric |
| Max Flow Rate | up to 3.17 GPM | Up to 4.4GMP | 3.4 GPM | 4.22 GPM | 4.3 GPM | – | 4.3 GPM |
| Heating Capacity | 13kW | 18kW | 14kW | 18 kW | 18kW | 18kW | 18kW |
| Installation Location | – | Indoor | – | – | – | – | – |
| Voltage | 240V | 240 Volt | 240V | 240 V | 240V | 240V | 240V |
| Fixture Capacity | – | – | 2 Point of Use | 2-3 Point of Use | – | 3–4 simultaneous usage points | 2-3 points of use |
| Temperature Range | – | 80°F to 140°F | 86-140℉ | – | – | 86°F to 131°F | – |
| Installation Type | – | – | – | Whole House | Whole House | Whole House | – |
| Features | Tankless | Tankless | Tankless | Tankless | Tankless | Tankless | Tankless, LED Display |
| Application | – | Shower | Point of Use | Point of Use | – | – | – |
| Form Factor | – | – | Compact | Compact | – | – | – |
| Wattage | – | 18 kW | 14 kW | 18 kW | 18 kW | 18 kW | 18 kW |
| Intended Use | – | – | Home | Home | – | – | – |
| Dimensions | 12.6 × 8.25 × 3.63 inches | 13.1 × 13.1 × 17.1 inches | 9.56 × 9.56 × 12.6 inches | 8 × 8 × 11 inches | 19.1 × 11.1 × 4 inches | 12.2 × 12.2 × 17.3 inches | 9.7 × 9.7 × 14 inches |
| Weight | 3.97 pounds | – | – | – | 12 pounds | – | 12 pounds |
| Size | Compact | 240V/18kW | M-14 | M-18 | 18kW | – | WN-18 |
| Color | Gray | Gray | Gray | Snow | Gray | Gray | Gray |
| Model | RTEX-13 | ET180 | – | HEU-ET018A5W-M0 | WN18 | TSB-180 | YQ-WN18K |
03 Frequently asked questions
Which Rheem 13kW compact electric tankless alternative offers the highest flow rate?
The WINTEMP 18kW model with WiFi control provides the highest flow rate at 4.3 GPM. This output supports whole-house hot water needs in a compact footprint. It requires an electrical panel that can handle the high amperage draw for consistent performance.
Are there smart home compatible options to the Rheem 13kW unit?
Yes, the Westinghouse 14kW and WINTEMP 18kW models include WiFi connectivity. These units allow you to manage settings remotely via a smartphone app. They fit users who value smart integration alongside compact sizing for point-of-use or whole-house applications.
What is the smallest alternative to the Rheem 13kW tankless heater?
The Rheem 13kW unit itself remains the most compact option at 8.25 by 3.63 by 12.6 inches. Among alternatives, the Orbek 18kW model is also very small, measuring 8 by 11 by 8 inches. Both fit tight wall-mounted spaces effectively.
Can I replace my Rheem 13kW with an 18kW model for whole-house use?
Yes, several 18kW models like the Orbek, WINTEMP, and SIVUATEK are designed for whole-house installation. These higher wattage units deliver more hot water for multiple fixtures. You must ensure your home has the necessary electrical capacity, often requiring dual breakers.
Which alternative includes an LED display for temperature feedback?
The WINTEMP 18kW Electric Tankless Water Heater features an LED display. This provides clear visual feedback on water temperature and system status. It suits buyers who prioritize easy monitoring and ETL safety certification for their hot water system.
Is there a budget-friendly electric tankless alternative to the Rheem 13kW?
The Orbek 18kW model is identified as the best budget choice. It offers solid 18kW power and ETL certification for whole-house heating. This compact, wall-mount design provides a cost-effective solution for buyers needing reliable performance without premium features.
Which Rheem 13kW alternative is best for homes with 80A electrical capacity?
The Thermomate 18kW Electric Tankless Water Heater is best for homes with 80A electrical capacity. It offers reliable performance with precise temperature settings. This model fits buyers who prioritize heating power and compact dimensions over maximum flow capacity for specific applications.
