Tankless water heaters with thermostat controls deliver hot water on demand while making it easier to set and maintain a comfortable temperature. The right model can save space, reduce standby losses, and provide efficient heating for a sink, shower, or multiple fixtures.
This roundup compares 10 electric options, including compact 110V point-of-use heaters, 240V multi-fixture units, and smart models with features such as Wi-Fi connectivity and digital temperature displays. Use the buying guide below to match capacity, installation requirements, and controls to your home.
Best 10 Tankless Water Heaters with Thermostat Picks for 2026
Smart Whole-Home Pick
Westinghouse 14kW WiFi Tankless Heater
- WiFi, voice control, and temperature memory
- Up to 3.4 GPM under specified conditions
- ETL certified with multiple safety protections
Best For: Smart homes and compact residential installations
Under-Sink Thermostat Pick
GE 2.5-Gallon Mini Tank Heater
- Adjustable temperature and power knob
- Compact 120V wall- or floor-mount design
- Works standalone or as a hot-water booster
Best For: Point-of-use hot water in compact spaces
High-Output Thermostat Choice
Rheem 18kW Electric Tankless Heater
- External digital thermostat with LED display
- Self-modulating 18kW operation
- Flow rate up to 4.4 GPM
Best For: Whole-home use with higher hot-water demand
Compact Low-Demand Pick
EcoSmart ECO 8 Tankless Heater
- Compact 8kW wall-mount design
- LED display and up to 2 GPM flow
- Listed 99.8% efficiency and lifetime limited electronics warranty
Best For: Small spaces and lower-demand applications
Best High-Capacity Pick
Rheem RTEX-11 11kW Tankless Heater
- Up to 2.68 GPM
- 1-degree digital thermostat control
- Requires 240V, 50-amp circuit
Best For: Compatible multiple-fixture applications needing higher output
Best Under-Sink Value
110V 3000W Digital Tankless Heater
- LCD temperature display
- Compact point-of-use design
- Not suitable for showers
Best For: Low-flow sinks, apartments, RVs, and camping
Best Mid-Range Rheem
Rheem RTEX-08 8kW Tankless Heater
- Up to 1.95 GPM
- Adjustable digital temperature display
- Requires 240V, 40-amp circuit
Best For: Moderate-demand multiple-fixture installations
Compact Under-Sink Pick
3000W 110V Electric Tankless Heater
- LED display with adjustable Fahrenheit/Celsius settings
- Compact wall-mounted design for tight spaces
- Designed for low-flow use, not showers
Best For: Under-sink, kitchen, RV, and camping applications
Thermostatic Point-of-Use Pick
- Maintains selected temperature within 1 degree
- Compact wall-mountable point-of-use design
- Supports flow rates up to 1.5 GPM
Best For: Single-fixture installations needing precise temperature control
Higher-Flow Whole-Use Option
- Provides up to 3.38 GPM for multiple fixtures
- Digital setting range from 86°F to 140°F
- Claims temperature stability within 1°F
Best For: Two to three points of use with adequate 240V electrical capacity
Smart Whole-Home Pick – Westinghouse 14kW WiFi Tankless Heater
For shoppers comparing tankless water heaters with thermostat controls, this 14kW Westinghouse model adds app-based temperature adjustment and voice control to compact electric, on-demand heating. It reaches hot water in about three seconds and can deliver up to 3.4 GPM under the stated test conditions.
Best For: Smart-home users needing a compact heater for apartments, homes, cabins, or office restrooms.
Pros:
- WiFi, Alexa, and Google Home compatibility with temperature memory.
- 98% thermal efficiency and up to 3.4 GPM under specified conditions.
- ETL certification and four-layer safety protection.
- Wall-mountable design takes no floor space.
Cons:
- Requires a dedicated 60A double-pole breaker and 6 AWG wire.
- Performance depends on inlet temperature and flow conditions.
This is a feature-rich choice when remote control and temperature retention matter, but its electrical requirements should be confirmed before installation.
Under-Sink Thermostat Pick – GE 2.5-Gallon Mini Tank Heater
This GE mini tank is a practical alternative for shoppers seeking tankless water heaters with thermostat-style temperature control in a small space. Its adjustable knob, 2.5-gallon capacity, and standard 120V power make it suited to point-of-use hot water rather than whole-home demand.
Best For: Kitchens, bathrooms, laundry areas, RVs, garages, and other point-of-use locations.
Pros:
- Adjustable temperature and power controls.
- Compact wall- or floor-mount design.
- Can operate alone or boost another water heater.
- Stainless steel heating element resists rust and corrosion.
Cons:
- Limited to 2.5 gallons of stored hot water.
- Not a tankless unit, despite its thermostat-focused use case.
Choose this model when simple installation and localized hot water are more important than continuous, whole-home output.
High-Output Thermostat Choice – Rheem 18kW Electric Tankless Heater
Among tankless water heaters with thermostat controls, the Rheem RTEX-18 stands out for its external digital thermostatic control and LED display. Its self-modulating 18kW system adjusts power to demand and is rated for flow up to 4.4 GPM.
Best For: Whole-home electric installations needing higher output and precise external temperature adjustment.
Pros:
- External digital control with LED display and ±1-degree accuracy.
- Self-modulation adjusts power to hot-water demand.
- Up to 4.4 GPM flow rate.
- Field-serviceable copper immersion heating elements.
Cons:
- Requires 240V electrical service.
- Higher-output installation may require careful electrical planning.
With its higher wattage, digital control, and demand-based modulation, this Rheem is a strong fit for buyers prioritizing whole-home performance and precise settings.
Compact Low-Demand Pick – EcoSmart ECO 8 Tankless Heater
The EcoSmart ECO 8 is a compact electric option for shoppers comparing tankless water heaters with thermostat-style digital controls. Its 8kW, 240V design is rated at up to 2 GPM, making it better suited to lower-demand applications than larger whole-home systems.
Best For: Compact wall-mounted installations with modest hot-water demand.
Pros:
- Small 8-inch-wide wall-mountable design.
- LED display for straightforward control.
- Up to 2 GPM flow rate with 99.8% listed efficiency.
- Lifetime warranty on electronics, exchanger, and element, excluding labor and incidental damage.
Cons:
- Lower 8kW output may not suit simultaneous high-demand use.
- Requires 240V power.
This model makes sense where installation space is tight and hot-water demand is limited, while its lower output should be considered before choosing it for whole-home use.
Best High-Capacity Pick – Rheem RTEX-11 11kW Tankless Heater
For shoppers comparing tankless water heaters with thermostat controls, the Rheem RTEX-11 offers digital temperature adjustment in 1-degree increments from 80°F to 140°F. Its 11kW output and stated flow rate of up to 2.68 GPM make it suited to selected multiple-fixture applications, provided your electrical service meets the requirements.
Best For: Homes needing a higher-output electric unit for compatible multiple-fixture use.
Pros:
- Digital thermostatic controls adjust in precise 1-degree increments.
- Provides up to 2.68 GPM according to the supplied specifications.
- Compact wall-mounted design requires no venting and saves floor space.
- 99.8% stated efficiency and on-demand heating help reduce standby energy use.
Cons:
- Requires 240V power, a 50-amp double-pole breaker, and recommended 100-amp household service.
- Correct sizing and professional installation are important for reliable operation.
The RTEX-11 is the stronger Rheem option here for flow-demanding applications, but its electrical requirements should be confirmed before purchase. Its precise thermostat controls and vent-free installation make it a practical electric upgrade when the home’s service can support it.
Best Under-Sink Value – 110V 3000W Digital Tankless Heater
This compact 110V unit is a practical choice among tankless water heaters with thermostat-style digital controls for point-of-use hot water. Its LCD display, selectable Fahrenheit or Celsius settings, and 3000W heating system are designed for sinks and other small applications rather than showers.
Best For: Kitchen sinks, bathroom sinks, apartments, RVs, and other low-flow point-of-use locations.
Pros:
- LCD display and selectable Fahrenheit or Celsius temperature settings.
- Compact wall-mounted design with standard 1/2-inch NPT connections.
- Includes dry-boil, leakage, overheating, inactivity, and IPX4 protection features.
- Backed by a stated 24-month warranty.
Cons:
- Not suitable for showers, which typically require at least 1.8 GPM.
- Must be installed vertically according to the supplied instructions.
- Requires appropriate wiring and a trip switch rated over 32A.
This model makes the most sense when you need localized hot water without a storage tank. Its low-flow design and installation limitations rule it out for whole-home or shower use, but the display and safety features are useful for an under-sink setup.
Best Mid-Range Rheem – Rheem RTEX-08 8kW Tankless Heater
The Rheem RTEX-08 is a compact option for buyers seeking tankless water heaters with thermostat controls and 240V electric operation. Its adjustable digital temperature display, 1.95 GPM stated capacity, and point-of-use format make it appropriate for selected multiple-fixture applications when properly sized.
Best For: Smaller multiple-fixture installations that can support a dedicated 240V electrical circuit.
Pros:
- Digital temperature display with adjustable controls.
- Provides up to 1.95 GPM according to the supplied specifications.
- Compact wall-mounted design is 90% smaller than traditional tank water heaters, according to the product notes.
- Heats water on demand and includes a 5-year leak and 1-year parts warranty.
Cons:
- Requires 240V power, a 40-amp double-pole breaker, and recommended 100-amp household service.
- Lower stated flow capacity than the Rheem 11kW model.
- Professional sizing and installation are recommended.
The RTEX-08 balances Rheem’s precise digital control format with a lower 8kW output. It is a sensible fit for compatible, moderate-demand installations, but buyers should verify both expected flow needs and electrical capacity before choosing it.
Compact Under-Sink Pick – 3000W 110V Electric Tankless Heater
If you need tankless water heaters with thermostat-style temperature adjustment for a sink or other low-flow fixture, this compact 110V model offers a practical point-of-use option. Its LED display supports Fahrenheit or Celsius settings, while the 3000W heater is designed for quick warming in kitchens, bathrooms, apartments, RVs, and camping setups.
Best For: Under-sink and low-flow point-of-use applications where compact size and standard 110V power are priorities.
Pros:
- LED display with Fahrenheit and Celsius settings.
- Compact, wall-mounted design saves space.
- Includes dry-burning, leakage, over-temperature, and inactivity protection.
- ETL-standard unit with 1/2-inch NPT connections.
Cons:
- Not suitable for showers, which typically require at least 1.8 GPM.
- Requires 13 AWG wiring and a circuit breaker rated at 32 amps or higher.
- Vertical installation is required.
This is best viewed as a compact fixture-level heater rather than a whole-home solution. Confirm the wiring, breaker, orientation, and expected flow rate before installation.
Thermostatic Point-of-Use Pick – Rheem RTEX-06T 6.5kW
The Rheem RTEX-06T is a strong choice among tankless water heaters with thermostat control when you want consistent temperature at a single point of use. Its thermostatic system continuously monitors water temperature and flow, targeting performance within 1 degree of the selected temperature while using power only when hot water is needed.
Best For: Point-of-use installations that need compact sizing, thermostatic control, and up to 1.5 GPM flow.
Pros:
- Thermostatic control maintains temperature within 1 degree of the selected setting.
- Compact wall-mountable design is 90% smaller than traditional tank heaters.
- 6.5kW output and 1.5 GPM flow rate suit point-of-use applications.
- Heats water only when it is being used.
Cons:
- Requires a 240V electrical supply.
- Its point-of-use design and 1.5 GPM flow rate may not suit larger simultaneous demands.
- Maximum temperature is listed as 140°F.
With its explicit thermostatic control and very small wall-mounted footprint, this Rheem model is well suited to targeted installations. Check your electrical service and fixture flow requirements before choosing it.
Higher-Flow Whole-Use Option – ORBEK 14kW 240V Heater
For shoppers comparing tankless water heaters with thermostat-style digital temperature control, the ORBEK 14kW model offers higher flow and precise adjustment for demanding residential use. It delivers up to 3.38 GPM, supports settings from 86°F to 140°F, and is designed to keep water temperature within 1°F when properly installed.
Best For: Homes needing higher-flow on-demand hot water for two to three points of use, such as a bathroom and kitchen.
Pros:
- Up to 3.38 GPM for two to three points of use.
- Digital controls allow temperature settings from 86°F to 140°F.
- Built-in chip is designed to maintain temperature within 1°F.
- ETL certified with leakage, over-temperature, dry-heating, and lightning protection.
Cons:
- Requires 240V hard wiring, a 60-amp two-pole breaker, and 6 AWG wiring.
- The household panel should have at least 150 amps of total capacity.
- Professional electrical planning may be necessary because of its high power demand.
This ORBEK is the most capable option of the three for higher-flow use, but its electrical requirements are substantial. Verify panel capacity, wiring, breaker requirements, and water connections before installation.
How We Picked the Best Tankless Water Heaters with Thermostat
We evaluated these Tankless Water Heaters with Thermostat controls and temperature-adjustment features based on electrical requirements, heating capacity, intended installation location, control type, flow-rate suitability, and practical use case. The selection includes compact under-sink models, point-of-use heaters, and larger 240V units designed to serve more than one fixture.
Because performance depends heavily on incoming water temperature and plumbing conditions, wattage alone does not determine output. We prioritized models that clearly communicate their installation format and provide useful temperature-control or monitoring features.
Quick Comparison
| Best For | What to Look For | Typical Category |
|---|---|---|
| Single sink or remote fixture | Compact size, 110V power, digital controls | 2.5- to 3kW point-of-use models |
| One shower or bathroom fixture | Higher wattage and adequate flow at your inlet temperature | 6- to 8kW heaters |
| Multiple fixtures | 240V circuit, higher output, and plumbing compatibility | 11- to 18kW models |
| Connected monitoring | Wi-Fi setup, app support, and accessible controls | Smart electric models |
Key Buying Factors for Tankless Water Heaters with Thermostat
Electrical Capacity
Check the voltage, amperage, breaker size, and wiring before buying. Many 240V heaters require a dedicated circuit and may need substantial electrical-service capacity. Compact 110V models are easier to install but generally support lower flow rates.
Flow Rate and Temperature Rise
A heater must raise incoming water to the desired temperature at the required flow rate. Cold climates and winter groundwater demand more power. Compare the manufacturer’s performance charts rather than assuming a listed wattage will support a whole home.
Controls and Thermostat Accuracy
Digital displays, thermostatic regulation, and adjustable temperature settings make operation more predictable and can help reduce scalding risk. Wi-Fi is useful for monitoring and adjustments, but it should not replace correctly configured temperature limits.
Installation and Protection
Confirm pipe connections, minimum activation flow, grounding, required shutoff valves, and whether the unit is approved for your intended location. Professional installation is strongly recommended for high-amperage 240V models. Follow local plumbing and electrical codes.
Who Should Buy Which Tankless Water Heaters with Thermostat?
Choose a compact 110V unit for a remote sink, office, workshop, or low-demand handwashing station. A thermostatic point-of-use model is a better fit when precise temperature control matters at one fixture. Select an 8kW heater for modest single-fixture demand, while 11kW to 14kW models are more appropriate for stronger bathroom or limited multi-fixture use when the electrical system supports them.
For larger homes or simultaneous use, consider an 18kW model only after confirming flow requirements, incoming water temperature, and available electrical capacity. A Wi-Fi-enabled heater suits homeowners who want remote monitoring, while a straightforward digital-display model may be the better value for a simple installation. In every case, verify sizing with the manufacturer’s specifications before purchase.