6 Best Alternatives to the Rheem 13kW Compact Electric Tankless Water Heater (2026)
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The Rheem 13kW Compact Electric Tankless Water Heater offers precise temperature control and a small footprint. If you need rheem 13kw compact electric tankless water heater alternatives, consider other models with different flow rates or features. This unit provides up to 3.17 GPM at 54 amps. Its compact dimensions make it easy to install in tight spaces. However, you might want more hot water for multiple fixtures. Some users prefer higher flow rates or remote control capabilities. Others may need a unit that fits a different electrical setup. We selected these options because their specifications overlap with the original. Each alternative addresses specific needs that the Rheem model may not fully satisfy. You can find units with higher wattage for whole-house use. You can also find models with WiFi for remote monitoring. This list helps you compare specs to find the right fit.
Key Differences in Flow and Size
ThermoMate 14kW Electric Tankless Water Heater
The ThermoMate 14kW model increases power slightly to 14 kW compared to the Rheem’s 13 kW. It measures 11.2 by 15.9 by 11.2 inches, which is taller and deeper than the Rheem’s compact 8.25 by 12.6 by 3.63 inches footprint. At 13 pounds, it is significantly heavier than the Rheem’s 3.97 pounds. You get more wattage for light household use, but you sacrifice the ultra-compact profile. Choose this if you need a bit more heating capacity and have the wall space for a larger unit.
Ranein 18kW 4.3 GPM Electric Water Heater
The Ranein 18kW unit jumps to 18 kW and delivers up to 4.3 GPM, which is higher than the Rheem’s 3.17 GPM limit. It is much larger, measuring 13.8 by 18.7 by 13.8 inches and weighing 17.4 pounds. This model is designed for whole-house hot water needs rather than single-fixture use. You gain significant flow rate but require more electrical capacity and installation space. Pick this alternative if you need to supply multiple bathrooms simultaneously and can handle the larger physical dimensions.
WINTEMP 18 kW Tankless Water Heater with WiFi
The WINTEMP 18kW heater also offers 18 kW of power and WiFi connectivity, which the Rheem lacks. It measures 11.1 by 4 by 19.1 inches and weighs 12 pounds. While it shares the 240V requirement, the added WiFi feature allows for remote control. The flow rate supports up to 4.3 GPM in mild climates. You trade the Rheem’s simple digital display for smart home integration. Select this option if you want to monitor and adjust temperatures remotely from your phone.
EcoSmart 13 kW Electric Tankless Water Heater
The EcoSmart ECO 11 matches the Rheem’s 13 kW wattage but is designed for single-sink or small bathroom use. It measures 13.5 by 10 by 6.5 inches and weighs 6.5 pounds. It is slightly wider and heavier than the Rheem but offers a similar compact form factor. This unit provides comparable performance for low-demand applications. You get a similar power level without the need for higher electrical capacity. Choose this if you want a direct 13 kW alternative with a slightly different dimensional profile for tight spaces.
Orbek 18kW 240V Tankless Electric Water Heater
The Orbek 18kW model provides 18 kW of power, exceeding the Rheem’s 13 kW output. It is designed for whole-house use and requires a dual 40-amp electrical setup. The unit measures 8 by 11 by 8 inches, which is wider than the Rheem’s depth but narrower in height. It is a robust option for homes with high electrical capacity. You gain significant hot water flow for multiple fixtures. Opt for this if you need whole-house coverage and have the necessary electrical infrastructure installed.
SIVUATEK 18 kW Electric Tankless Water Heater
The SIVUATEK 18kW heater offers 18 kW of power in a black finish, contrasting with the Rheem’s gray color. It measures 11 by 3 by 15 inches and weighs 19 pounds. It is thinner than the Rheem at only 3 inches deep but heavier. This model is ideal for high-flow point-of-use installations like a single bathroom or laundry room. You get more power and a slim profile but less height. Choose this alternative if you need a powerful heater that fits in narrow vertical spaces.
Quick picks
Our 7 picks
Rheem 13kW Compact Electric Tankless Water Heater
Best for: Compact installations with precise temp needs
- Voltage
- 240V
- Dimensions
- 12.6 × 8.25 × 3.63 inches
- Weight
- 3.97 pounds
View on Amazon: Rheem 13kW Compact Electric Tankless Water Heater Affiliate link
The Rheem RTEX-13 is a 13kW, 240V electric tankless water heater designed for compact spaces. It delivers up to 3.17 GPM with 99.8% energy efficiency. The unit features self-modulating power control and an external digital thermostat with 1-degree accuracy. Its small footprint measures 12.6 inches in length and weighs just 3.97 pounds. This model suits homeowners needing precise temperature control in tight installations.
Pros
- 13kW heating capacity with 3.17 GPM flow rate
- 99.8% energy efficiency rating
- External digital thermostat with 1-degree adjustment accuracy
- Self-modulating power control for consistent output
- Compact dimensions: 12.6 x 8.25 x 3.63 inches
Cons
- Lower flow rate than 18kW competitors on this list
- No built-in WiFi or smart home connectivity
- Requires 54-amp circuit breaker for installation
Good fit if
- You need a compact unit for tight spaces
- You want precise temperature control with digital display
- You have a dedicated 54-amp electrical circuit
Skip if
- You need whole-house hot water for multiple bathrooms
- You prefer WiFi-enabled smart controls
- You cannot install a 54-amp electrical circuit
Verdict: Rheem RTEX-13 Compact Electric fits users who prioritize precise temperature control and space efficiency over maximum flow rate. It is ideal for single-bathroom setups or small households with adequate electrical capacity.
ThermoMate 14kW Electric Tankless Water Heater
Best for: Small homes with adequate electrical capacity
- Fuel Type
- Electric
- Flow Rate
- 3.4 GPM
- Wattage
- 14 kW
- Installation Location
- Indoor
- Voltage
- 240 V
- Temperature Control
- 86°F to 131°F
View on Amazon: ThermoMate 14kW Electric Tankless Water Heater Affiliate link
The ThermoMate EH140 delivers up to 3.4 GPM of hot water at 240 volts. Its 14 kW cast aluminum heating element provides steady temperatures between 86°F and 131°F. This compact unit measures 15.9 by 11.2 by 3 inches and weighs 13 pounds. It suits small homes or apartments where you need to run one or two fixtures simultaneously without running out of hot water.
Pros
- 14 kW power output supports up to 3.4 GPM flow rate
- Compact dimensions of 15.9 x 11.2 x 3 inches save space
- ETL listed for safety with anti-leakage and over-temperature protection
- Self-modulating chip maintains stable water temperature
Cons
- Requires a dedicated 60 Amp double-pole circuit breaker
- Needs 6 AWG copper wires for proper installation
- Limited to indoor installation only
Good fit if
- You have a 150 Amp main electrical panel
- You need hot water for one or two fixtures at once
- You want a compact unit for a small closet or bathroom
Skip if
- You cannot install a 60 Amp double-pole breaker
- You need outdoor installation capability
- You require higher flow rates for multiple simultaneous showers
Verdict: ThermoMate 14kW Electric Tankless Water Heater fits users with strong electrical capacity who need reliable hot water for light household use. Its compact size and safety certifications make it a solid option for small spaces.
Ranein 18kW 4.3 GPM Electric Water Heater
Best for: whole-house hot water with high flow
- Fuel Type
- Electric
- Flow Rate
- 4.3 GPM
- Wattage
- 18 kW
- Voltage
- 240 V
- Temperature Control
- 86°F to 131°F, 1°F increments
- Certification
- CSA
View on Amazon: Ranein 18kW 4.3 GPM Electric Water Heater Affiliate link
The Ranein 18kW unit delivers up to 4.3 GPM at 240V, making it suitable for whole-house use. It features 99% thermal efficiency and precise temperature control from 86°F to 131°F in 1°F increments. You get continuous hot water for multiple outlets without standby loss. The compact design saves space, and CSA certification ensures safety. This model fits well if you need high flow and stable heat.
Pros
- High 18 kW power output for strong performance
- Max flow rate of 4.3 GPM supports multiple outlets
- Precise temperature adjustment in 1°F increments
- 99% thermal efficiency reduces energy consumption
- CSA certified for safety standards
Cons
- Requires two dedicated 240V circuits with 40A breakers
- Uses 8 AWG cables for installation
- Heavier at 17.4 pounds than some compact alternatives
Good fit if
- You need a whole-house solution with high flow
- You want precise temperature control in small increments
- You have the electrical capacity for dual 40A breakers
Skip if
- You cannot install two dedicated 240V circuits
- You prefer a lighter unit under 15 pounds
- You only need to heat one sink at a time
Verdict: Ranein 18kW Electric Tankless Water Heater offers robust 4.3 GPM flow and precise heating for whole-house needs, provided you can handle the dual-circuit electrical requirements.
WINTEMP 18 kW Tankless Water Heater with WiFi
Best for: mild climates with WiFi control needs
- Fuel Type
- Electric
- Flow Rate
- Up to 4.3 GPM
- Wattage
- 18 kW
- Voltage
- 240V
- Certification
- ETL
- Dimensions
- 19.2 x 11.1 x 4 inches
View on Amazon: WINTEMP 18 kW Tankless Water Heater with WiFi Affiliate link
The WINTEMP 18kW unit delivers up to 4.3 GPM at 240V. It uses self-modulating technology to adjust power based on flow and inlet temperature. The compact design measures 11.1 inches wide by 19.2 inches high. WiFi control lets you adjust settings remotely. ETL certification confirms safety standards. This model suits homes in mild climates with moderate hot water demands.
Pros
- 18kW heating element provides 4.3 GPM flow rate
- WiFi remote control for temperature adjustment
- Self-modulating technology optimizes energy usage
- ETL certified for safety compliance
Cons
- Requires 2 x 40 Amp breakers and 8/2 AWG wiring
- 12-pound weight may need sturdy mounting
- Limited to mild to moderate climate conditions
Good fit if
- You need remote temperature control via WiFi
- You have a 150 Amp household service
- You want ETL certified safety standards
Skip if
- You live in a cold climate requiring higher flow
- You cannot install dual 40 Amp breakers
- You prefer a simpler wiring setup
Verdict: WINTEMP 18kW Electric Tankless Water Heater fits users who value remote control and efficient energy use. It is ideal for mild climates where 4.3 GPM meets your needs.
EcoSmart 13 kW Electric Tankless Water Heater
Best for: single sink or small bathroom use
- Fuel Type
- Electric
- Wattage
- 13 kW
- Voltage
- 240 V
- Dimensions
- 10 x 13.5 x 6.5 inches
- Weight
- 6.5 pounds
View on Amazon: EcoSmart 13 kW Electric Tankless Water Heater Affiliate link
The EcoSmart ECO 11 is a 13 kW electric tankless water heater designed for point-of-use applications. It operates on 240 volts and measures 10 x 13.5 x 6.5 inches. The unit weighs 6.5 pounds and features self-modulating technology. You should consider this model if you need a compact solution for a single sink or small bathroom where space is limited.
Pros
- 13 kW heating capacity for instant hot water
- Compact dimensions of 10 x 13.5 x 6.5 inches
- Lightweight at 6.5 pounds for easy mounting
- Self-modulating technology adjusts energy use
Cons
- Lower 13 kW output compared to 18 kW competitors
- Small physical footprint limits flow for whole-house use
- No WiFi or smart home integration listed
Good fit if
- You need a heater for a single sink
- You have limited space in a cabinet
- You want a lightweight electric unit
Skip if
- You need hot water for multiple fixtures
- You require WiFi connectivity for remote control
- You need higher flow rates for showers
Verdict: EcoSmart ECO 11 13kW Compact Heater is a space-saving option for single-fixture use. It fits buyers who prioritize compact size over high flow capacity.
Orbek 18kW 240V Tankless Electric Water Heater
Best for: Whole-house hot water with high electrical capacity
- Fuel Type
- Electric
- Flow Rate
- 4.22 GPM
- Wattage
- 18 kW
- Voltage
- 240V
- Certification
- ETL
- Dimensions
- 17 x 13 x 3.9 inches
View on Amazon: Orbek 18kW 240V Tankless Electric Water Heater Affiliate link
This Orbek unit delivers 18 kW of heating power at 240 volts, targeting whole-house use for 2-3 points. It measures 17 inches high and 13 inches wide, with a slim 3.9-inch depth for wall mounting. The system uses self-modulating technology to adjust power based on flow, aiming for energy efficiency. It includes ETL certification and multiple safety protections like overheat and dry-fire prevention.
Pros
- 18 kW heating capacity for higher flow rates
- Self-modulating power reduces energy use during low flow
- Compact 3.9-inch depth saves wall space
- ETL certified for safety standards
- Includes leakage and overheat protection features
Cons
- Requires two 40-amp double-pole breakers
- Needs 8/2 AWG wiring for installation
- Maximum amperage draw of 75 amps
Good fit if
- You need whole-house hot water for multiple fixtures
- You have the electrical capacity for dual 40-amp breakers
- You want a wall-mounted unit with minimal depth
Skip if
- You cannot install dual 40-amp breakers
- You lack space for 8/2 AWG wiring
- You prefer a unit with lower electrical demands
Verdict: Orbek 18kW Electric Tankless Water Heater suits homes needing robust hot water flow for several points, provided you can support the required dual 40-amp electrical setup.
SIVUATEK 18 kW Electric Tankless Water Heater
Best for: High-flow point-of-use installations
- Fuel Type
- Electric
- Flow Rate
- 4.3 GPM
- Wattage
- 18 kW
- Voltage
- 240V
- Certification
- ETL
- Use
- Whole House
View on Amazon: SIVUATEK 18 kW Electric Tankless Water Heater Affiliate link
The SIVUATEK V7B-180B is a compact, self-modulating electric tankless water heater delivering up to 4.3 GPM. It operates on 240V with an 18kW heating element, providing endless hot water for point-of-use installations. The unit features ETL certification and a specialized heating chamber that separates water and electrical lines. Its slim 3-inch profile saves space, making it suitable for bathrooms or laundry areas where space is limited.
Pros
- High 18kW power output for strong flow rates
- Self-modulating technology adjusts power to flow rate
- Compact 3-inch depth for easy installation
- ETL listed for safety compliance
Cons
- Requires 40A double pole circuit breaker
- Uses 8AWG wiring which may need panel upgrade
- No digital temperature display mentioned in data
Good fit if
- You need a compact unit for point-of-use installation
- You have a dedicated 240V 40A circuit available
- You want high flow rate for a single fixture
Skip if
- You require a whole-house solution for multiple bathrooms
- You lack space for 40A breaker and 8AWG wiring
- You prefer a unit with visible digital controls
Verdict: The SIVUATEK 18kW Electric Tankless Water Heater offers high performance in a small footprint. It is ideal for homeowners needing a powerful, space-saving heater for a single bathroom or laundry room.
Specifications side by side
| Spec | Rheem 13kW Compact Electric Tankless Water Heater | ThermoMate 14kW Electric Tankless Water Heater | Ranein 18kW 4.3 GPM Electric Water Heater | WINTEMP 18 kW Tankless Water Heater with WiFi | EcoSmart 13 kW Electric Tankless Water Heater | Orbek 18kW 240V Tankless Electric Water Heater | SIVUATEK 18 kW Electric Tankless Water Heater |
|---|---|---|---|---|---|---|---|
| Fuel Type | not stated | Electric | Electric | Electric | Electric | Electric | Electric |
| Flow Rate | not stated | 3.4 GPM | 4.3 GPM | Up to 4.3 GPM | not stated | 4.22 GPM | 4.3 GPM |
| Wattage | not stated | 14 kW | 18 kW | 18 kW | 13 kW | 18 kW | 18 kW |
| Installation Location | not stated | Indoor | not stated | not stated | not stated | not stated | not stated |
| Voltage | not stated | 240 V | 240 V | 240V | 240 V | 240V | 240V |
| Temperature Control | not stated | 86°F to 131°F | 86°F to 131°F, 1°F increments | not stated | not stated | not stated | not stated |
| Certification | not stated | ETL | CSA | ETL | not stated | ETL | ETL |
| Dimensions | not stated | 15.9" x 11.2" x 3" | not stated | 19.2 x 11.1 x 4 inches | 10 x 13.5 x 6.5 inches | 17 x 13 x 3.9 inches | not stated |
| Use | not stated | not stated | Whole House | Whole House | not stated | Whole House | Whole House |
| Features | not stated | not stated | not stated | WiFi | not stated | not stated | not stated |
| Weight | 3.97 pounds | 13 pounds | 17.4 pounds | 12 pounds | 6.5 pounds | not stated | 19 pounds |
| Size | Compact | not stated | not stated | 18kW | 12 x 8 x 4 | M-18 | M-18 |
| Color | Gray | Gray | Gray | Gray | color | Snow | Black |
| Model | RTEX-13 | EH140 | RE18K | WN18 | ECO 11 | HEU-ET018A5W-M0 | V7B-180B |
Frequently asked questions
Which alternative offers the highest flow rate for whole-house use?
The Ranein 18kW model provides 4.3 GPM, making it the top choice for whole-house needs. It uses 18 kW of power to support higher flow demands. This unit requires a dual-circuit electrical setup to operate effectively. If your home has adequate electrical capacity, this heater delivers robust hot water for multiple fixtures simultaneously.
How does the ThermoMate 14kW compare in size to the Rheem?
The ThermoMate 14kW is larger than the compact Rheem unit. It measures 11.2 by 15.9 by 11.2 inches, while the Rheem is significantly smaller at 8.25 by 12.6 by 3.63 inches. The ThermoMate weighs 13 pounds, which is heavier than the Rheem’s 3.97 pounds. You need more space for the ThermoMate installation.
Can I control the WINTEMP heater remotely?
Yes, the WINTEMP 18kW model includes WiFi capabilities for remote control. This feature allows you to manage settings from a distance. It is ideal for users in mild climates who want efficient energy use. The unit maintains a compact height of 4 inches, though it is longer at 19.1 inches.
Which option is best for a single bathroom sink?
The EcoSmart 13 kW is designed for single-fixture use. It measures 13.5 by 10 by 6.5 inches and weighs only 6.5 pounds. This compact size makes it perfect for small spaces like a single sink or small bathroom. It provides 13 kW of power, which is sufficient for limited hot water demand.
Does the Orbek heater require special electrical wiring?
The Orbek 18kW model requires a dual 40-amp electrical setup. This high power demand supports its whole-house capabilities. You must ensure your home’s electrical system can handle this load before installation. The unit is compact, measuring 8 by 11 by 8 inches, but the electrical requirements are significant.
What is the smallest footprint among the alternatives?
The Orbek 18kW has a very small footprint, measuring 8 by 11 by 8 inches. The Rheem is also compact at 8.25 by 12.6 by 3.63 inches. The ThermoMate and Ranein models are larger. If space is your primary constraint, the Orbek and Rheem offer the tightest fit for your installation area.
Is the SIVUATEK suitable for point-of-use installations?
Yes, the SIVUATEK 18 kW is ideal for high-flow point-of-use installations. It offers 18 kW of power in a small footprint. The unit measures 11 by 3 by 15 inches, making it suitable for a single bathroom or laundry room. It weighs 19 pounds, so you need a sturdy mounting location.