6 Best Alternatives to the Westinghouse 8kW Tankless Water Heater (2026)
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The Westinghouse 8kW Tankless Water Heater delivers instant hot water for single sinks with smart WiFi control. Its compact 6.9 x 8.1 x 2.5 inch size fits tight under-sink spaces. This 240V electric unit offers precise temperature settings between 80°F and 130°F. It includes anti-scale protection and six safety features for reliable daily use. However, you might need more power for showers or whole-house demands. The 8kW rating limits flow rate for high-demand fixtures. Some buyers prefer larger units or different brand options for better durability. Others may want higher wattage for multiple simultaneous uses. You might also seek a different size or simpler manual controls instead of smart features. These alternatives were chosen because their specifications overlap with the original. They share similar voltage, fuel type, or installation requirements. This list helps you find a better fit for your specific hot water needs. We compared seven models to ensure you have practical choices. Each option meets distinct household demands while maintaining core tankless benefits.
Our top pick: Westinghouse 8kW Smart WiFi Tankless Water Heater.
How these alternatives differ
Rheem 8 kW Multi-Fixture Tankless Water Heater
The Rheem RTEX-08 matches the Westinghouse at 8 kW and 240V, making it a direct power swap for single-sink use. It drops the WiFi connectivity and smart app control found in the Westinghouse model. You get a purely manual interface instead. The physical footprint shifts to 12.6 x 8.25 x 3.63 inches, which is longer but slightly taller than the Westinghouse. It weighs 8 pounds. This unit suits buyers who want a reliable, brand-name compact heater without needing remote temperature adjustments. It is a straightforward, no-frills point-of-use solution for tight spaces where smart features are unnecessary.
Stiebel Eltron Tempra 29 Plus 28.8kW Tankless
The Stiebel Eltron Tempra 29 Plus jumps to 28.8 kW, offering vastly more heating power than the 8 kW Westinghouse. This unit is designed for whole-home use or high-demand fixtures, not single sinks. It requires significant electrical capacity compared to the Westinghouse’s 40A circuit. The size is much larger at 16.6 x 14.5 x 4.63 inches and weighs 19 pounds. It lacks WiFi and smart home integration, relying on manual digital controls. This heater is for users with strong electrical service who need substantial hot water volume. It trades compactness and smart features for raw heating performance and durability.
Ranein 8kW Electric Tankless Water Heater
The Ranein 8kW matches the Westinghouse wattage and voltage but removes all smart capabilities. It offers manual temperature control only, with no app or voice assistant compatibility. The dimensions are 9.06 x 6.7 x 9.06 inches, creating a square footprint that differs from the Westinghouse’s rectangular shape. It is designed for single-point installations like sinks or showers. This unit is a budget-friendly alternative for buyers who do not need WiFi features. It provides the same 8 kW heating power in a simpler, more affordable package. You sacrifice remote monitoring and precise digital presets for a lower cost and basic functionality.
WINTEMP 36kW Electric Tankless Water Heater
The WINTEMP 36kW is a high-power unit at 36 kW, far exceeding the 8 kW Westinghouse. It is built for large homes with robust electrical infrastructure, not single sinks. It includes WiFi control, similar to the Westinghouse, allowing remote temperature management. The size is significantly larger at 13.7 x 21.1 x 13.7 inches and weighs 36.1 pounds. This heater is for users who need whole-house hot water capacity. It offers smart features but demands more space and electrical support. It is the choice for those who want the convenience of app control with much higher heating output.
Westinghouse 24kW WiFi Tankless Water Heater
The Westinghouse 24kW WiFi unit keeps the brand and smart features but triples the power to 24 kW. It is designed for whole-house use rather than single sinks. The size is 13 x 17.1 x 13 inches, much larger than the 8kW model. It retains WiFi connectivity for remote control and temperature adjustments. This heater suits buyers who want the same smart ecosystem but need more hot water capacity. It requires a stronger electrical service than the 8kW version. You get the familiar interface and app control with significantly higher performance for busy households.
WINTEMP 18 kW Smart WiFi Tankless Water Heater
The WINTEMP 18kW offers a middle ground with 18 kW of power, double the Westinghouse’s 8 kW. It includes WiFi control, matching the smart features of the original. The dimensions are 13 x 15.9 x 13 inches, larger than the compact 8kW model. It weighs 19.5 pounds. This unit is for smaller households or multi-fixture setups that need more power than a single sink but less than a whole-house system. It provides smart connectivity and increased heating capacity. You gain more hot water flow while keeping remote control features, at the cost of a larger physical footprint.
Quick picks
Our 7 picks
Westinghouse 8kW Smart WiFi Tankless Water Heater
Best for: single sink hot water with smart control
- Fuel Type
- Electric
- Wattage
- 8 kW
- Voltage
- 240 V
- Temperature Control
- 80°F-130°F
- Dimensions
- 6.9" x 8.1" x 2.5"
- Use
- Under Sink
View on Amazon: Westinghouse 8kW Smart WiFi Tankless Water Heater Affiliate link
This compact 8kW electric unit delivers instant hot water for single-fixture use. It measures just 6.9 by 8.1 by 2.5 inches, fitting easily under sinks. The 240V system requires a dedicated 40A circuit. Smart WiFi control lets you adjust temperatures between 80°F and 130°F via an app or voice commands. It is designed specifically for handwashing and dish rinsing rather than whole-house supply.
Pros
- Compact 6.9 x 8.1 x 2.5 inch size fits tight spaces
- WiFi control for remote temperature adjustment from 80°F to 130°F
- Anti-scale separated heating element reduces maintenance
- Six built-in safety protections including dry-fire prevention
Cons
- 8kW output is insufficient for shower use
- Requires a dedicated 40A circuit for installation
- Limited to single-fixture applications only
Good fit if
- You need hot water for a single kitchen or bathroom sink
- You want to control water temperature remotely via an app
- You have limited space under a vanity or counter
Skip if
- You require hot water for a shower or bathtub
- You cannot install a dedicated 40A electrical circuit
- You need a unit to serve multiple fixtures simultaneously
Verdict: Westinghouse 8kW WiFi Electric Heater is a practical solution for users who need reliable, smart-controlled hot water for a single sink. It fits well in tight spaces but lacks the power for higher-demand fixtures like showers.
Rheem 8 kW Multi-Fixture Tankless Water Heater
Best for: Single fixture point-of-use installations
- Fuel Type
- Electric
- Voltage
- 240V
- Wattage
- 8 kW
- Dimensions
- 12.6 × 8.25 × 3.63 inches
- Weight
- 8 pounds
View on Amazon: Rheem 8 kW Multi-Fixture Tankless Water Heater Affiliate link
The Rheem RTEX-08 is a compact 8kW unit designed for point-of-use applications. It delivers up to 1.95 GPM at 240V. The digital thermostat adjusts in 1-degree increments from 80°F to 140°F. Its small footprint saves space compared to traditional tanks. This model suits single fixtures like sinks or showers where high flow is not required.
Pros
- Delivers up to 1.95 GPM for single fixture use
- Digital controls allow 1-degree temperature adjustments
- Compact dimensions of 12.6 x 8.25 x 3.63 inches
- Weighs only 8 pounds for easy mounting
Cons
- Low flow rate limits use to single fixtures
- Requires a 40-amp double-pole breaker
- Needs #8 AWG copper conductors for wiring
Good fit if
- You need hot water for a single sink or shower
- You have limited space for installation
- You want precise temperature control in 1-degree steps
Skip if
- You need to supply hot water to multiple fixtures simultaneously
- Your electrical panel cannot support a 40-amp breaker
- You require whole-house hot water capacity
Verdict: Rheem 8kW Electric Tankless Water Heater is a compact solution for single-fixture hot water needs. It fits well in tight spaces where high flow is not necessary.
Stiebel Eltron Tempra 29 Plus 28.8kW Tankless
Best for: high-demand households with strong electrical service
- Fuel Type
- Electric
- Wattage
- 28.8 kW
- Voltage
- 208 V, 240 V
- Dimensions
- 14.5 x 16.6 x 4.63 in
- Use
- Whole House
- Weight
- 19 pounds
View on Amazon: Stiebel Eltron Tempra 29 Plus 28.8kW Tankless Affiliate link
The Stiebel Eltron Tempra 29 Plus delivers 28.8kW of electric heating power at 240V. It measures 14.5 by 16.6 by 4.63 inches and weighs 19 pounds. The unit includes two temperature memory presets for quick adjustments. You need three dedicated 40-amp breakers and 8-gauge copper wiring for installation. This high-capacity model suits households needing strong hot water flow for multiple fixtures.
Pros
- 28.8kW output at 240V for high flow rates
- Two temperature memory presets for easy adjustment
- Compact dimensions of 14.5 x 16.6 x 4.63 inches
- No venting required for indoor installation
Cons
- Requires three separate 40-amp breakers
- Needs 8-gauge copper wiring
- No smart WiFi connectivity listed in specifications
Good fit if
- You have a 200-amp electrical service panel
- You need high flow for whole-house use
- You prefer manual temperature presets over apps
Skip if
- You only have a single 40-amp breaker available
- You want built-in WiFi control features
- Your electrical panel is below 200 amps
Verdict: Stiebel Eltron Tempra 29 Plus 28.8kW is a robust electric heater for homes with ample electrical capacity. It fits buyers who prioritize raw heating power and reliable manual controls over smart features.
Ranein 8kW Electric Tankless Water Heater
Best for: single sink or shower installations
- Fuel Type
- Electric
- Flow Rate
- Up to 1.9 GPM
- Wattage
- 8 kW
- Voltage
- 240 V
- Temperature Control
- 86°F to 131°F, 1°F increments
- Dimensions
- 9.06" × 6.7" × 2.34"
View on Amazon: Ranein 8kW Electric Tankless Water Heater Affiliate link
The Ranein 8kW unit delivers 1.9 GPM at 240V with 99% thermal efficiency. Its compact 9.06 x 6.7 x 2.34 inch frame fits tight spaces. You get precise temperature control from 86°F to 131°F in 1°F increments via an LED display and knob. It suits single-sink or shower applications where space and budget matter.
Pros
- 99% thermal efficiency for energy savings
- Compact 9.06 x 6.7 x 2.34 inch size
- Precise 1°F temperature adjustment increments
- Integrated LED display for easy monitoring
- Built-in overheat and leakage protection
Cons
- Low 1.9 GPM flow rate limits use to one fixture
- Requires a dedicated 40-amp circuit breaker
- Manual knob controls lack smart connectivity
Good fit if
- You need a compact heater for a single sink or shower
- You want precise temperature settings in 1°F increments
- You prefer manual knob controls over digital interfaces
Skip if
- You need to supply hot water to multiple fixtures simultaneously
- You require WiFi or app-based remote control
- You cannot install a dedicated 40-amp circuit
Verdict: The Ranein 8kW Electric Tankless Water Heater fits single-point installations where space is tight and precise manual temperature control is preferred. It is not suitable for whole-house demands or smart home integration.
WINTEMP 36kW Electric Tankless Water Heater
Best for: large homes with strong electrical service
- Fuel Type
- Electric
- Flow Rate
- Up to 8.7 GPM
- Wattage
- 36 kW
- Voltage
- 240V
- Certification
- ETL
- Dimensions
- 21.5 x 13.7 x 5.2 inches
View on Amazon: WINTEMP 36kW Electric Tankless Water Heater Affiliate link
This WINTEMP unit delivers 36 kW of power at 240V, supporting up to 8.7 GPM flow. It uses self-modulating technology to adjust output based on incoming water temperature. The device includes WiFi control and ETL certification for safety. It is designed for homes with three to five bathrooms in mild climates. The compact wall-mounted design saves space compared to traditional tanks.
Pros
- 36 kW high power output for multiple fixtures
- 8.7 GPM maximum flow rate
- Built-in WiFi for smartphone temperature control
- ETL certified for safety reliability
Cons
- Requires 150A electrical service and four 40A breakers
- Heavy at 36.1 pounds
- Only includes a 2-year replacement warranty
Good fit if
- You have a 300A household electrical service
- You need hot water for three to five bathrooms
- You want WiFi remote temperature adjustment
Skip if
- You have a standard 100A or 200A electrical panel
- You live in a cold climate with low inlet water temps
- You cannot install four 40A double-pole circuit breakers
Verdict: WINTEMP 36kW Electric Tankless Heater provides substantial hot water capacity for large households with the right electrical infrastructure. It fits buyers who can support the high amperage draw and want smart control features.
Westinghouse 24kW WiFi Tankless Water Heater
Best for: high-flow whole-house electric needs
- Fuel Type
- Electric
- Flow Rate
- Max 5.55 GPM
- Wattage
- 24 kW
- Voltage
- 240V
- Certification
- ETL
- Dimensions
- 17" x 13" x 4.3"
View on Amazon: Westinghouse 24kW WiFi Tankless Water Heater Affiliate link
This 24kW electric unit delivers up to 5.55 GPM at 240V, making it suitable for whole-house use. It features smart WiFi control via app or voice commands. The compact design measures 17.1 inches high and 13 inches wide. It requires a 100A electrical setup with three 40A breakers. This model fits homes needing high flow rates for multiple fixtures.
Pros
- 24kW power output for high flow
- 5.55 GPM maximum flow rate
- Smart WiFi and voice control
- Compact 17.1-inch height design
Cons
- Requires 100A electrical capacity
- Heavy 17-pound build
- No included temperature display mentioned
Good fit if
- You need whole-house hot water
- You have a 100A electrical panel
- You want smart home integration
Skip if
- You only have a 40A circuit
- You need gas fuel type
- You require a built-in display
Verdict: Westinghouse 24kW Whole House Heater offers high capacity for busy homes. It suits buyers with strong electrical systems who want smart features.
WINTEMP 18 kW Smart WiFi Tankless Water Heater
Best for: Smart home integration and compact installation
- Fuel Type
- Electric
- Flow Rate
- Up to 4.3 GPM
- Wattage
- 18 kW
- Voltage
- 240V
- Temperature Control
- 86°F–140°F
- Certification
- ETL
View on Amazon: WINTEMP 18 kW Smart WiFi Tankless Water Heater Affiliate link
The WINTEMP WM18V delivers 18 kW of power at 240V, producing up to 4.3 GPM of hot water. It features WiFi control via the Tuya Smart app, allowing you to set temperatures between 86°F and 140°F remotely. The unit measures 15.9 x 13 x 4.2 inches and weighs 19.5 pounds. This model suits households needing reliable flow for two to three simultaneous fixtures while maintaining precise temperature control.
Pros
- 18 kW output provides up to 4.3 GPM
- WiFi app control for remote temperature adjustment
- Compact 15.9 x 13 x 4.2 inch design
- ETL certified for safety and reliability
Cons
- Requires 2 x 40 Amp breakers and 8 AWG wiring
- Limited to 18 kW compared to 36 kW alternatives
- 2-year manufacturer warranty is shorter than industry standard
Good fit if
- You need precise digital temperature control via an app
- You have the electrical capacity for dual 40 Amp circuits
- You want a compact unit for limited wall space
Skip if
- You require higher flow rates for multiple bathrooms
- You cannot install dedicated 8 AWG wiring
- You prefer a longer warranty period than two years
Verdict: WINTEMP 18kW Electric Tankless Water Heater fits users who prioritize smart connectivity and compact sizing over raw power. It is ideal for smaller households with adequate electrical infrastructure who want to manage water temperature remotely.
Specifications side by side
| Spec | Westinghouse 8kW Smart WiFi Tankless Water Heater | Rheem 8 kW Multi-Fixture Tankless Water Heater | Stiebel Eltron Tempra 29 Plus 28.8kW Tankless | Ranein 8kW Electric Tankless Water Heater | WINTEMP 36kW Electric Tankless Water Heater | Westinghouse 24kW WiFi Tankless Water Heater | WINTEMP 18 kW Smart WiFi Tankless Water Heater |
|---|---|---|---|---|---|---|---|
| Fuel Type | Electric | not stated | Electric | Electric | Electric | Electric | Electric |
| Flow Rate | not stated | not stated | not stated | Up to 1.9 GPM | Up to 8.7 GPM | Max 5.55 GPM | Up to 4.3 GPM |
| Wattage | 8 kW | not stated | 28.8 kW | 8 kW | 36 kW | 24 kW | 18 kW |
| Voltage | 240 V | not stated | 208 V, 240 V | 240 V | 240V | 240V | 240V |
| Temperature Control | 80°F-130°F | not stated | not stated | 86°F to 131°F, 1°F increments | not stated | not stated | 86°F–140°F |
| Certification | not stated | not stated | not stated | not stated | ETL | ETL | ETL |
| Dimensions | 6.9" x 8.1" x 2.5" | not stated | 14.5 x 16.6 x 4.63 in | 9.06" × 6.7" × 2.34" | 21.5 x 13.7 x 5.2 inches | 17" x 13" x 4.3" | 15.9″H × 13″W × 4.2″D |
| Use | Under Sink | not stated | Whole House | not stated | Whole House | Whole House | Whole House |
| Features | WiFi | not stated | not stated | not stated | WiFi | WiFi | WiFi |
| Weight | not stated | 8 pounds | 19 pounds | not stated | 36.1 pounds | 17 pounds | 19.5 pounds |
| Size | S-8 | not stated | 29 (kW) | not stated | 36kW | L-24 | 18 (kW) |
| Color | Gray | Gray | White | Gray | Gray | Gray 24 | Gray |
| Model | WET-08K-B | RTEX-08 | 239223 | RE8K-U (8kW) | WN36 | WET-24K-G | WM18V |
If you also evaluate drinking water filtration, compare apec water apec tankless ro water alternatives by flow rate and dimensions.
Frequently asked questions
Can I use an 8kW heater for a shower?
An 8kW unit is generally best for a single sink. It may struggle to provide enough hot water for a shower, especially in colder climates. For shower use, consider a higher wattage model like the WINTEMP 36kW or the Westinghouse 24kW. These units offer more power to handle higher flow rates effectively.
What is the difference between the Rheem and Westinghouse 8kW models?
Both units provide 8kW of power at 240V for single-fixture use. The Westinghouse model includes WiFi connectivity for smart control. The Rheem RTEX-08 is a purely manual unit without smart features. You choose the Westinghouse for app control and the Rheem for a simpler, non-connected setup.
Which alternative is best for whole-house hot water?
The Westinghouse 24kW is the best whole-house option in this list. It provides significantly more power than the 8kW models. For larger homes, the WINTEMP 36kW is also suitable. These higher-wattage units support multiple fixtures simultaneously, unlike the single-sink focused 8kW heaters.
Do any of these heaters have WiFi control?
Yes, several models include WiFi features. The Westinghouse 8kW, WINTEMP 36kW, Westinghouse 24kW, and WINTEMP 18kW all support smart connectivity. The Rheem 8kW, Stiebel Eltron Tempra 29 Plus, and Ranein 8kW are manual units. Choose a WiFi model if you want to adjust settings remotely.
Is the Stiebel Eltron Tempra 29 Plus powerful enough?
The Stiebel Eltron Tempra 29 Plus offers 28.8kW of heating power. This is much stronger than the 8kW alternatives. It is designed for high-demand households with strong electrical service. It provides reliable manual controls rather than smart features, making it a robust choice for heavy usage.
Which unit is the most compact for tight spaces?
The Westinghouse 8kW is extremely compact, measuring just 2.48 inches in width and length. It fits well in tight under-sink areas. The Rheem 8kW is also small at 3.63 inches in height. Both are ideal for point-of-use installations where space is limited compared to larger whole-house units.
Can the Ranein 8kW handle a whole house?
No, the Ranein 8kW is not suitable for whole-house demands. It is designed for single sink or shower installations. Its 8kW output is limited to point-of-use applications. For a whole house, you need a higher wattage model like the WINTEMP 36kW or the Westinghouse 24kW.