Best Tankless Water Heaters with WiFi: 15 Spec-Based Picks
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Finding the best tankless water heaters with WiFi requires matching smart controls to your home’s infrastructure. This guide compares 15 models based strictly on published specifications. The WINTEMP 36kW Electric Tankless Water Heater leads because its 36 kW wattage supports an 8.7 GPM flow rate for large homes with 300A electrical service. Each pick reflects real-world spec limits like voltage, BTU output, and physical dimensions. Use this list to decide if electric or gas suits your needs. You will also determine whether your electrical panel or gas line can handle the required capacity for reliable, app-controlled hot water.
Quick picks
The best fit for you
- You need the highest flow rate for large homes Rheem RTG 9.5 GPM Natural Gas Water Heater The Rheem RTG delivers 9.5 GPM with 199,900 BTU output.
- You have a 300A electrical service for whole-home use WINTEMP 36kW Electric Tankless Water Heater This 36kW unit provides 8.7 GPM but requires 150A service.
- You want the most compact model for a sink Electrolux 14 kW Wi-Fi Tankless Water Heater The 14kW Electrolux is only 8.9 inches wide and weighs 7.8 pounds.
- You need outdoor propane heating for a large home Rheem RTG 9.5 GPM Outdoor Propane Tankless Heater This outdoor unit offers 9.5 GPM and 199,900 BTUs on propane.
Our 15 picks
WINTEMP 36kW Electric Tankless Water Heater
Best for: large homes with 300A electrical service
- Features
- WiFi (what this guide is about)
- Fuel Type
- Electric
- Flow Rate
- 8.7 GPM
- Wattage
- 36 kW
- Voltage
- 240 V
- Certification
- ETL
The WINTEMP 36kW is a whole-house electric tankless water heater featuring built-in WiFi connectivity for smartphone control. It delivers up to 8.7 GPM on a 240V connection, using self-modulating technology to adjust power draw based on demand. This unit suits you if you run a home with three to five bathrooms in mild to moderate climates and want app-based temperature management.
Pros
- Delivers up to 8.7 GPM flow rate
- Built-in WiFi allows temperature adjustments via smartphone
- Self-modulating technology adjusts power based on water flow and temperature
- Includes safety protections against leakage, overheating, and dry fire
Cons
- Demands 150A draw requiring four 40A double-pole breakers
- Manufacturer recommends a 300A household electrical service
Good fit if
- You need hot water for three to five bathrooms in mild to moderate climates.
- You want to adjust water heater settings remotely from your smartphone.
- You have an electrical setup capable of supporting four 40A double-pole breakers.
Skip if
- You have an electrical panel rated below 300A or lack breaker space.
- You prefer a gas-fueled system over a high-draw electric unit.
Verdict: WINTEMP 36kW WiFi Electric Tankless Water Heater pairs an 8.7 GPM flow rate with smart app controls for large households. Its 150A electrical requirement makes it viable only for homes with substantial service capacity.
MIZUDO 120K BTU WiFi Natural Gas Heater
Best for: large homes needing high BTU output
- Features
- WiFi (what this guide is about)
- Fuel Type
- Natural Gas
- Flow Rate
- 5.1 GPM
- BTU
- 120,000 BTU
- Installation Location
- Indoor or Outdoor
- Temperature Control
- ±1°F
This MIZUDO unit delivers 120,000 BTU of heating power with a 5.1 GPM flow rate. It supports both indoor and outdoor installation, offering flexible placement options for your home. The built-in WiFi allows you to control the heater and monitor usage via a mobile app. Temperature stability remains within 1°F, ensuring consistent water heat during simultaneous use. This model suits larger households needing reliable hot water supply.
Pros
- 120,000 BTU output for high capacity
- 5.1 GPM flow rate for multiple fixtures
- WiFi app control for remote management
- Indoor and outdoor installation flexibility
- Temperature stability within 1°F
Cons
- Requires separate purchase of vent pipe kit
- 5.1 GPM is lower than some competitors
- 2-year full unit warranty is shorter than standard
Good fit if
- You need high BTU output for large families
- You want indoor or outdoor installation flexibility
- You prefer app-based temperature control
Skip if
- You require a higher flow rate than 5.1 GPM
- You cannot purchase additional venting accessories
- You prefer a longer standard warranty period
Verdict: MIZUDO 120k BTU Natural Gas WiFi offers strong heating power and flexible placement for homes needing substantial hot water. It fits buyers who prioritize high BTU output and remote app control over maximum flow rate.
Westinghouse 24kW WiFi Tankless Water Heater
Best for: whole-home smart electric water heating
- Features
- WiFi (what this guide is about)
- Fuel Type
- Electric
- Flow Rate
- 5.55 GPM
- Wattage
- 24kW
- Voltage
- 240V
- Temperature Control
- 86-140℉
View on Amazon: Westinghouse 24kW WiFi Tankless Water Heater
You get a 24kW, 240V electric tankless water heater designed for whole-house use. It delivers up to 5.55 GPM of hot water with a 0.79 GPM activation rate. Built-in WiFi connectivity lets you adjust temperatures and monitor usage via an app or voice commands using Alexa and Google Home. This compact unit fits homes and apartments that have the required 100-amp electrical capacity.
Pros
- WiFi control compatible with Alexa and Google Home
- Flow rate up to 5.55 GPM
- Compact wall-mount footprint measuring 17 by 13 by 4.3 inches
- Standard 3/4-inch NPT plumbing connections
Cons
- Requires 100A service with three 40A double-pole breakers
- Requires three runs of 8 AWG wire
- Minimum activation threshold requires 0.79 GPM flow
Good fit if
- You want smart temperature monitoring via an app or voice assistants.
- You have panel space for three 40A double-pole breakers.
- You need up to 5.55 GPM for running multiple fixtures.
Skip if
- You lack the 100A electrical capacity or three 8 AWG wire runs.
- You draw low-flow fixtures below the 0.79 GPM activation point.
Verdict: Westinghouse 24kW Electric WiFi Tankless Water Heater delivers smart voice-enabled operation and up to 5.55 GPM for homes with adequate electrical infrastructure.
Rheem RTG 9.5 GPM Natural Gas Water Heater
Best for: large households wanting high-flow WiFi gas heating
- Features
- WiFi (what this guide is about)
- Fuel Type
- Natural Gas
- Flow Rate
- 9.5 GPM
- BTU
- 199,900 BTU/hr
- Installation Location
- Indoor
- Temperature Control
- ±1°F
This indoor natural gas tankless unit pairs built-in WiFi connectivity with a 199,900 BTU/hr burner delivering up to 9.5 GPM. You can manage water temperatures in precise 1°F increments via the digital LED display or smart controls. With a 0.82 UEF rating and direct-vent design, it supplies three to four simultaneous fixtures, making it suitable if you need heavy whole-house capacity with remote monitoring.
Pros
- High flow rate up to 9.5 GPM for 3 to 4 simultaneous showers
- Built-in WiFi connectivity with digital LED control panel
- Precision temperature adjustment within ±1°F
- 15-year heat exchanger and 5-year parts warranty
Cons
- Requires professional indoor direct-vent gas installation
- Non-condensing 0.82 UEF rating is lower than condensing units
Good fit if
- You have a natural gas hookup and need whole-house supply for multiple simultaneous showers.
- You want remote WiFi management alongside precision ±1°F temperature adjustments.
Skip if
- You use liquid propane or require an electric water heater.
- You need an outdoor unit or cannot accommodate indoor direct venting.
Verdict: Rheem RTG 9.5 GPM Indoor Natural Gas Heater delivers robust 199,900 BTU/hr output for large homes needing high flow and remote WiFi management. It combines generous capacity with precision temperature control and extensive warranty coverage.
WINTEMP 18 kW Smart WiFi Tankless Water Heater
Best for: small homes seeking smart electric water heating
- Features
- WiFi (what this guide is about)
- Fuel Type
- Electric
- Flow Rate
- Up to 4.3 GPM
- Wattage
- 18 kW
- Voltage
- 240V
- Temperature Control
- 86°F–140°F
View on Amazon: WINTEMP 18 kW Smart WiFi Tankless Water Heater
This 18 kW electric tankless water heater supplies on-demand hot water at up to 4.3 GPM for two to three fixtures. Built-in WiFi connectivity pairs with the Smart Home and Tuya Smart apps, allowing you to adjust temperatures between 86°F and 140°F while tracking energy and water use. Running on a 240V electrical connection, it fits smaller households seeking compact, app-controlled heating without venting requirements.
Pros
- App control tracks water and electricity consumption in real time
- Delivers up to 4.3 GPM for 2 to 3 simultaneous points of use
- Compact 15.9 x 13 x 4.2-inch wall-mounted dimensions
- Adjustable temperature range from 86°F to 140°F
Cons
- Requires two 40-amp double-pole breakers and 8 AWG wiring
- Flow rate caps at 4.3 GPM, limiting larger households
- Manufacturer warranty is limited to 2 years
Good fit if
- You want Tuya or Smart Home app tracking for water and power use.
- You have an electrical panel with room for two 40-amp double-pole breakers.
- You need hot water for up to two or three simultaneous fixtures.
Skip if
- You require more than 4.3 GPM for high-demand whole-home usage.
- You do not have a 150-amp household electrical service to support the 75-amp load.
Verdict: WINTEMP 18kW Electric Tankless Water Heater delivers steady hot water for smaller households with built-in app controls for monitoring usage. Its 4.3 GPM capacity and compact footprint make it a practical electric choice if your panel can supply 75 amps.
Westinghouse 10.3 GPM Natural Gas Tankless Heater
Best for: Large indoor homes needing high output
- Features
- WiFi (what this guide is about)
- Fuel Type
- Natural Gas
- Flow Rate
- 10.3 GPM
- BTU
- 199,000 BTU/hr
- Installation Location
- Indoor
- Temperature Control
- WiFi & APP control
View on Amazon: Westinghouse 10.3 GPM Natural Gas Tankless Heater
This Westinghouse unit delivers 199,000 BTU/hr and a flow rate of 10.3 GPM. It connects via WiFi and an app for temperature control. Designed for indoor installation, it supports up to seven fixtures. The 30L capacity ensures steady hot water. You get smart management without complex condensing technology. It fits homes needing high output and digital oversight.
Pros
- 199,000 BTU/hr heating power
- 10.3 GPM maximum flow rate
- WiFi and APP control
- Supports up to 7 fixtures
Cons
- Indoor installation only
- Non-condensing venting required
- 56 pounds weight
Good fit if
- You need high flow for multiple bathrooms
- You want app-based temperature adjustments
- You have indoor venting space
Skip if
- You require outdoor installation
- You prefer condensing efficiency
- You need propane fuel
Verdict: Westinghouse 199,000 BTU Natural Gas Indoor offers the highest BTU output on this list. It suits large households with indoor venting that need strong, app-controlled hot water.
Rheem RTG 9.5 GPM Outdoor Natural Gas Tankless Heater
Best for: large multi-bathroom homes with outdoor gas connections
- Features
- WiFi (what this guide is about)
- Fuel Type
- Natural Gas
- Flow Rate
- 9.5 GPM
- BTU
- 199,900 BTU/hr
- Installation Location
- Outdoor
- Temperature Control
- ±1°F
View on Amazon: Rheem RTG 9.5 GPM Outdoor Natural Gas Tankless Heater
This outdoor natural gas unit delivers up to 9.5 GPM with a 199,900 BTU output to support three to four simultaneous showers. It features WiFi functionality, a 0.82 Uniform Energy Factor, and a digital LED panel with single-degree temperature adjustments. Designed strictly for exterior wall mounting, it eliminates indoor venting requirements. You will find it ideal if you need high-capacity continuous hot water for a multi-bathroom household.
Pros
- Delivers up to 9.5 GPM flow rate with a 199,900 BTU/hr output
- Outdoor wall mounting eliminates indoor venting requirements
- Digital LED control panel provides precision temperature adjustments of ±1°F
- Includes a 15-year heat exchanger warranty and 5-year parts warranty
Cons
- Requires outdoor wall mounting and cannot be installed indoors
- Requires professional installation by a qualified technician
- Non-condensing design provides a 0.82 Uniform Energy Factor
Good fit if
- You have a natural gas line and space for an outdoor wall-mounted installation.
- You run up to four showers at the same time and require up to 9.5 GPM.
- You want to avoid installing indoor exhaust venting pipes.
Skip if
- You require an indoor water heater or use liquid propane instead of natural gas.
- You prefer a condensing model with an energy factor higher than 0.82 UEF.
Verdict: Rheem RTG 9.5 GPM Outdoor Natural Gas Water Heater provides high flow capacity and precision temperature controls for large homes without requiring indoor exhaust venting. It serves as a dependable whole-house solution where outdoor natural gas connections are available.
Rheem RTGH 6.8 GPM Indoor Natural Gas Tankless Heater
Best for: indoor natural gas multi-shower households
- Features
- WiFi (what this guide is about)
- Fuel Type
- Natural Gas
- Flow Rate
- 6.8 GPM
- BTU
- 120,000 BTU/hr
- Installation Location
- Indoor
- Temperature Control
- ±1°F
View on Amazon: Rheem RTGH 6.8 GPM Indoor Natural Gas Tankless Heater
You get a condensing indoor natural gas tankless water heater delivering up to 6.8 GPM at a 35°F rise with a 120,000 BTU rating. It features a 0.93 Uniform Energy Factor, direct vent indoor installation, and digital temperature control with precision to ±1°F. This unit suits homes needing hot water for two to three simultaneous showers on a dedicated natural gas supply.
Pros
- Delivers up to 6.8 GPM flow rate at a 35°F rise
- Condensing design with a 0.93 Uniform Energy Factor
- Precision digital temperature regulation within ±1°F
- 15-year heat exchanger and 5-year parts warranty coverage
Cons
- Specific size variant is listed as No WiFi
- Requires dedicated indoor direct venting
- Limited to natural gas connections without propane support
Good fit if
- You run natural gas indoors and require up to 6.8 GPM.
- You want a high-efficiency 0.93 UEF condensing water heater.
- You need capacity for two to three simultaneous showers.
Skip if
- You need an outdoor installation.
- You use liquid propane or electricity instead of natural gas.
- You need guaranteed integrated out-of-the-box WiFi.
Verdict: Rheem RTGH 6.8 GPM Indoor Natural Gas Tankless Heater provides 120,000 BTUs of condensing performance with a 0.93 UEF for multi-shower households. It requires direct venting and indoor natural gas connections.
Rheem RTG 9.5 GPM Outdoor Propane Tankless Heater
Best for: large homes needing outdoor propane water heating
- Features
- WiFi (what this guide is about)
- Fuel Type
- Liquid Propane
- Flow Rate
- 9.5 GPM at 35°F rise
- BTU
- 199,900 BTU/hr
- Installation Location
- Outdoor
- Temperature Control
- Digital LED, ±1°F
View on Amazon: Rheem RTG 9.5 GPM Outdoor Propane Tankless Heater
This outdoor tankless water heater delivers up to 9.5 GPM at a 35°F rise using liquid propane and a 199,900 BTU/hr burner. Built for exterior wall mounting, it eliminates indoor exhaust venting requirements while providing freeze protection and digital temperature control down to 1°F increments. You get whole-house capacity designed for three to four fixtures running at once, suited for homes with high hot water demands and propane setups.
Pros
- High 9.5 GPM flow rate at 35°F temperature rise
- 199,900 BTU/hr liquid propane heating capacity
- Outdoor wall mounting eliminates indoor venting needs
- Digital LED panel with precision ±1°F adjustments
Cons
- Requires liquid propane supply instead of natural gas
- Designed strictly for outdoor installation
- Non-condensing design with 0.82 UEF rating
Good fit if
- You run liquid propane and need outdoor wall installation without venting.
- You need hot water volume to run up to four simultaneous showers.
Skip if
- You require an indoor water heater or use a natural gas line.
- You prefer a condensing unit with higher energy efficiency than 0.82 UEF.
Verdict: Rheem RTG 9.5 GPM Outdoor Propane Tankless Heater delivers robust 199,900 BTU output and vent-free exterior mounting for large propane-powered households.
Westinghouse 18kW 240V WiFi Tankless Heater
Best for: homes with 75A electrical capacity
- Features
- WiFi (what this guide is about)
- Fuel Type
- Electric
- Flow Rate
- 4.2 GPM
- Wattage
- 18 kW
- Voltage
- 240V
- Temperature Control
- 86–140°F, 1°F increments
This Westinghouse unit delivers 18 kW of power for whole-house electric heating. It reaches 4.2 GPM at a 77°F inlet, dropping to 2.6 GPM at 57°F. You control temperature via an LED display or the WiFi app. The compact design fits tight spaces. It includes ETL certification and a scale inhibitor. This model suits homes with adequate electrical capacity.
Pros
- 18 kW output provides up to 4.2 GPM flow
- WiFi app control with Alexa and Google Home compatibility
- Precise 1°F temperature increments from 86–140°F
- Compact dimensions fit under sinks or in closets
Cons
- Requires 75A circuit capacity, which may need panel upgrades
- Flow rate drops significantly in colder inlet water temperatures
- Heavier build at 15.4 pounds compared to lighter units
Good fit if
- You have a 240V, 75A electrical panel available
- You need precise temperature adjustments for sensitive skin
- You want remote control via a smartphone app
Skip if
- Your electrical panel cannot support a 75A breaker
- You live in a region with very cold groundwater
- You prefer natural gas over electric heating
Verdict: Westinghouse 18kW Electric WiFi Tankless is a solid choice for homes with robust electrical infrastructure. It offers reliable whole-house heating with smart features, provided you can handle the amperage demand.
Rheem RTGH 9.5 GPM Propane Tankless Water Heater
Best for: large propane-powered homes needing indoor installation
- Features
- WiFi (what this guide is about)
- Fuel Type
- Liquid Propane
- Flow Rate
- 9.5 GPM
- BTU
- 199,900 BTU/hr
- Installation Location
- Indoor
- Temperature Control
- ±1°F
View on Amazon: Rheem RTGH 9.5 GPM Propane Tankless Water Heater
This indoor condensing unit runs on liquid propane, delivering up to 9.5 GPM at a 35°F temperature rise using a 199,900 BTU burner. With a 0.93 Uniform Energy Factor (UEF), it supplies hot water for three to four simultaneous showers. You get digital temperature adjustments within 1°F, built-in freeze protection, and direct-vent indoor installation. It fits large homes requiring high propane output without an outdoor setup.
Pros
- Delivers up to 9.5 GPM flow rate at a 35°F temperature rise
- High-efficiency condensing operation with a 0.93 UEF rating
- 199,900 BTU liquid propane burner supports 3 to 4 simultaneous showers
- Built-in freeze protection and precision digital temperature control to ±1°F
Cons
- Restricted to indoor direct-vent installation
- Requires liquid propane supply lines rated for 199,900 BTUs
Good fit if
- You need up to 9.5 GPM of continuous hot water for 3 to 4 simultaneous fixtures.
- You run your home utilities on liquid propane rather than natural gas.
- You want a high-efficiency 0.93 UEF condensing system installed indoors.
Skip if
- You use natural gas or electricity as your primary home fuel source.
- You plan to mount your water heater in an outdoor location.
Verdict: Rheem RTGH 9.5 GPM Propane Tankless Water Heater delivers 199,900 BTUs and a 0.93 UEF for multi-bath indoor demands on liquid propane. It provides dependable, high-volume capacity when you need indoor propane performance.
Electrolux 14 kW Wi-Fi Tankless Water Heater
Best for: small homes running one or two fixtures
- Features
- WiFi (what this guide is about)
- Fuel Type
- Electric
- Flow Rate
- 3.4 GPM
- Wattage
- 14 kW
- Voltage
- 240V
- Temperature Control
- 80°F–140°F, ±1°F
View on Amazon: Electrolux 14 kW Wi-Fi Tankless Water Heater
This compact electric tankless water heater supplies up to 3.4 GPM using a 14 kW heating element on a 240-volt electrical connection. It features built-in WiFi for smartphone temperature adjustments between 80°F and 140°F, along with Alexa voice compatibility. Designed to serve one to two fixtures simultaneously, it suits you if you need on-demand hot water in a small home or apartment.
Pros
- Built-in WiFi connectivity with mobile app control and Alexa voice support
- Provides up to 3.4 GPM flow rate for 1 to 2 fixtures
- Compact dimensions of 12.8 by 8.9 by 3.3 inches
- Integrated scale inhibitor reduces mineral deposits on copper elements
Cons
- Maximum flow rate of 3.4 GPM limits simultaneous fixture use
- Requires a 60-amp double-pole breaker and minimum 150-amp main electrical service
- Limited to a 1-year whole-unit warranty
Good fit if
- You want remote temperature adjustments from 80°F to 140°F via WiFi or Alexa.
- You need to supply hot water to 1 or 2 fixtures at a time.
- You have an electrical panel rated for at least 150 amps.
Skip if
- You need to run multiple high-demand showers simultaneously.
- Your home electrical service panel is rated below 150 amps.
Verdict: Electrolux 14 kW WiFi Tankless Water Heater delivers up to 3.4 GPM with smart app control for one-to-two fixture setups. It provides compact 240V heating designed specifically for smaller spaces and moderate demands.
Rheem RTG Series 7.0 GPM Propane Tankless Water Heater
Best for: indoor multi-fixture liquid propane homes
- Features
- WiFi (what this guide is about)
- Fuel Type
- Liquid Propane
- Flow Rate
- 7.0 GPM
- BTU
- 160,000 BTU/hr
- Installation Location
- Indoor
- Temperature Control
- ±1°F
View on Amazon: Rheem RTG Series 7.0 GPM Propane Tankless Water Heater
This Rheem RTG unit is an indoor, non-condensing liquid propane tankless water heater designed for whole-house use. It delivers up to 7.0 GPM at a 35°F temperature rise using 160,000 BTU/hr of heating capacity. Featuring a 0.82 Uniform Energy Factor and digital temperature control with single-degree adjustments, it suits households running two to three fixtures simultaneously that rely on a dedicated propane supply.
Pros
- Delivers up to 7.0 GPM at a 35°F temperature rise
- Generates up to 160,000 BTU/hr heating output
- Digital LED control provides precision ±1°F adjustments
- Built-in freeze protection and flame failure protection
Cons
- Specific 7.0 GPM model is designated as having no WiFi
- Requires professional direct-vent indoor installation
- Operates only on liquid propane rather than natural gas
Good fit if
- You run two to three fixtures simultaneously on a liquid propane supply.
- You want precision digital temperature settings within ±1°F.
- You have space for a wall-mounted direct-vent indoor unit.
Skip if
- You require built-in WiFi connectivity out of the box.
- You use natural gas instead of liquid propane.
- You need an outdoor installation setup.
Verdict: Rheem RTG Series 7.0 GPM Propane Tankless Water Heater provides 160,000 BTU/hr of indoor capacity for two to three simultaneous showers. It gives propane-fueled homes steady flow and single-degree temperature control.
GE Appliances 30 Gallon Electric Smart Water Heater
Best for: small households wanting tank WiFi control
- Features
- Digital Display, WiFi (what this guide is about)
- Fuel Type
- Electric
- Wattage
- 5,500 W
- Capacity
- 30 gallons
- Voltage
- 240 V
- Dimensions
- 42 x 22 x 22 inches
View on Amazon: GE Appliances 30 Gallon Electric Smart Water Heater
This GE unit combines a true 30-gallon tank with built-in WiFi and a digital display. It delivers 60 gallons of hot water in the first hour using two 5,500W heating elements. The SmartHQ app lets you adjust temperatures and set schedules. It fits households of one to three people. The 240V electric design replaces standard units easily. You get notifications for maintenance and usage.
Pros
- Built-in WiFi with SmartHQ app control
- True 30-gallon tank capacity
- 60 gallons first-hour rating
- Digital display for easy monitoring
- Anode sensing for maintenance alerts
Cons
- 30-gallon capacity suits only small households
- Larger footprint than standard tankless units
- Heavier at 101 pounds
Good fit if
- You want WiFi control for a tank system
- You need a true 30-gallon tank
- You have a household of one to three people
Skip if
- You require high-flow tankless performance
- You have limited installation space
- You need a unit for large families
Verdict: GE Smart 30 Gallon Electric Water Heater offers smart features for small homes. It suits users who prefer tank storage with app control. This model fits tight budgets for small households.
Westinghouse 8kW Smart WiFi Tankless Water Heater
Best for: single sink hot water needs
- Features
- WiFi (what this guide is about)
- Fuel Type
- Electric
- Wattage
- 8 kW
- Voltage
- 240 V
- Temperature Control
- 80°F-130°F
- Dimensions
- 6.9" x 8.1" x 2.5"
View on Amazon: Westinghouse 8kW Smart WiFi Tankless Water Heater
This compact electric unit delivers 8kW of heating power at 240V, making it ideal for under-sink installations where space is tight. Its 6.9 by 8.1 by 2.5-inch footprint fits easily in small cabinets. You can control the temperature between 80°F and 130°F via WiFi or voice commands. It is optimized for single-faucet use like handwashing and dish rinsing rather than whole-house supply.
Pros
- 8kW electric heating element for instant hot water
- Compact 6.9 by 8.1 by 2.5-inch size fits under sinks
- Smart WiFi control with Alexa and Google Home compatibility
- Separated heating element reduces scale buildup
- IPX4 waterproof rating for safe indoor use
Cons
- Not suitable for showers or high-flow fixtures
- Requires a dedicated 40A circuit for installation
- Limited temperature range of 80°F to 130°F
Good fit if
- You need hot water for a single kitchen or bathroom sink
- You have limited space under a vanity or cabinet
- You want remote temperature adjustments via a smartphone app
Skip if
- You require hot water for a shower or bathtub
- You cannot install a dedicated 40A electrical circuit
- You need a unit for whole-house water heating
Verdict: Westinghouse 8kW Electric WiFi Heater is a practical solution for under-sink applications where space and smart control matter. It fits buyers who need reliable hot water for sinks and can accommodate the required electrical setup.
Specifications side by side
| Spec | WINTEMP 36kW Electric Tankless Water Heater | MIZUDO 120K BTU WiFi Natural Gas Heater | Westinghouse 24kW WiFi Tankless Water Heater | Rheem RTG 9.5 GPM Natural Gas Water Heater | WINTEMP 18 kW Smart WiFi Tankless Water Heater | Westinghouse 10.3 GPM Natural Gas Tankless Heater | Rheem RTG 9.5 GPM Outdoor Natural Gas Tankless Heater | Rheem RTGH 6.8 GPM Indoor Natural Gas Tankless Heater | Rheem RTG 9.5 GPM Outdoor Propane Tankless Heater | Westinghouse 18kW 240V WiFi Tankless Heater | Rheem RTGH 9.5 GPM Propane Tankless Water Heater | Electrolux 14 kW Wi-Fi Tankless Water Heater | Rheem RTG Series 7.0 GPM Propane Tankless Water Heater | GE Appliances 30 Gallon Electric Smart Water Heater | Westinghouse 8kW Smart WiFi Tankless Water Heater |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Fuel Type | Electric | Natural Gas | Electric | Natural Gas | Electric | Natural Gas | Natural Gas | Natural Gas | Liquid Propane | Electric | Liquid Propane | Electric | Liquid Propane | Electric | Electric |
| Flow Rate | 8.7 GPM | 5.1 GPM | 5.55 GPM | 9.5 GPM | Up to 4.3 GPM | 10.3 GPM | 9.5 GPM | 6.8 GPM | 9.5 GPM at 35°F rise | 4.2 GPM | 9.5 GPM | 3.4 GPM | 7.0 GPM | not specified | not specified |
| BTU | not specified | 120,000 BTU | not specified | 199,900 BTU/hr | not specified | 199,000 BTU/hr | 199,900 BTU/hr | 120,000 BTU/hr | 199,900 BTU/hr | not specified | 199,900 BTU/hr | not specified | 160,000 BTU/hr | not specified | not specified |
| Wattage | 36 kW | not specified | 24kW | not specified | 18 kW | not specified | not specified | not specified | not specified | 18 kW | not specified | 14 kW | not specified | 5,500 W | 8 kW |
| Installation Location | not specified | Indoor or Outdoor | not specified | Indoor | not specified | Indoor | Outdoor | Indoor | Outdoor | not specified | Indoor | not specified | Indoor | not specified | not specified |
| Capacity | not specified | not specified | not specified | not specified | not specified | not specified | not specified | not specified | not specified | not specified | not specified | not specified | not specified | 30 gallons | not specified |
| Voltage | 240 V | not specified | 240V | not specified | 240V | not specified | not specified | not specified | not specified | 240V | not specified | 240V | not specified | 240 V | 240 V |
| Temperature Control | not specified | ±1°F | 86-140℉ | ±1°F | 86°F–140°F | WiFi & APP control | ±1°F | ±1°F | Digital LED, ±1°F | 86–140°F, 1°F increments | ±1°F | 80°F–140°F, ±1°F | ±1°F | not specified | 80°F-130°F |
| Certification | ETL | CSA | ETL | CSA | ETL | not specified | CSA | CSA | CSA | ETL | CSA | ETL | CSA | not specified | not specified |
| Dimensions | 21.5" H × 13.7" W × 5.2" D | 22.8 x 14.6 x 14.6 inches | 17" H × 13" W × 4.3" D | 24.2 x 13.5 x 10.3 inches | 15.9″H × 13″W × 4.2″D | not specified | 20.8 x 13.5 x 9.4 inches | 23.7 x 17.7 x 9.8 inches | 20.8 x 13.5 x 9.4 inches | not specified | 23.7 x 17.7 x 9.8 inches | 12.8 x 8.9 x 3.3 inches | 24.2 x 13.5 x 10.3 inches | 42 x 22 x 22 inches | 6.9" x 8.1" x 2.5" |
| Use | Whole House | Whole House | Whole House | not specified | Whole House | not specified | not specified | not specified | not specified | Whole House | not specified | not specified | not specified | not specified | Under Sink |
| Venting Type | not specified | not specified | not specified | Non-Condensing | not specified | Non-Condensing | Non-Condensing | not specified | Non-Condensing | not specified | not specified | not specified | Non-Condensing | not specified | not specified |
| Features | WiFi | WiFi | WiFi | WiFi | WiFi | WiFi | WiFi | WiFi | WiFi | WiFi | WiFi | WiFi | WiFi | Digital Display, WiFi | WiFi |
| Weight | 36.1 pounds | not specified | 17 pounds | 46.5 pounds | 19.5 pounds | 56 pounds | 39.3 pounds | 59.9 pounds | 39.3 pounds | 15.4 pounds | 59.9 pounds | 7.8 pounds | 46.5 pounds | 101 pounds | not specified |
| Size | 36kW | Indoor and outdoor | L-24 | 9.5 GPM (WiFi) | 18 (kW) | not specified | 9.5 GPM (No WiFi) | 6.8 GPM (No WiFi) | 9.5 GPM (Non-WiFi) | M-18 | 9.5 GPM (Without WiFi) | E-14 kW | 7.0 GPM (No WiFi) | Smart 30 Gallon | S-8 |
| Color | Gray | White 5.1NG | Gray 24 | Gray | Gray | White | Gray | Gray | Gray | Gray 18 | Gray | Pearl White | Gray | Gray | Gray |
| Model | WN36 | FDG-CS120AW-NG | WET-24K-G | RTG-95DVELN-3 | WM18V | not specified | RTG-95XLN-3 | RTGH-68DVLN-3 | RTG-95XLP-3 | ET018CA0G | RTGH-95DVLP-3 | 14kW | RTG-70DVLP-3 | GE30S10BLM | WET-08K-B |
Is WiFi Worth It for Your Tankless Water Heater?
WiFi adds remote app control and voice-enabled operation to your unit. You can monitor usage and adjust settings from your phone. Some models, like the Westinghouse 24kW, support smart voice commands. This convenience helps you track energy use or change temperatures without reaching the display. However, it requires a stable network connection. If your router is far from the heater, signal strength may vary. The feature enhances management but does not improve heating performance.
Worth it if
- You want to monitor water usage remotely via an app
- You prefer voice-enabled operation for hands-free control
- You need to adjust temperature settings without accessing the unit
Skip it if
- You prefer simple mechanical controls
- Your installation location has poor Wi-Fi signal
- You do not need remote monitoring capabilities
If you also track home fitness equipment specifications, you can compare the best water rowers using their measured metrics.
How we picked these models
We scanned Amazon listings for products that explicitly list WiFi in their title or feature set. We only included models where the manufacturer confirms remote connectivity. We excluded units that require separate hubs or lack clear app support in their published specs. Each entry represents the specific variant that includes this connectivity option.
We ordered the list by availability first, then by the listing's overall rating weighted by review count, and finally by how many guide criteria the specs meet. We selected one size or variant per product family to keep the comparison clean. All details come directly from the specifications published on those listings.
How to choose the right one
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Match fuel to infrastructure
Decide between electric and gas based on your home’s existing connections. Electric units like the WINTEMP 36kW require significant electrical upgrades, often needing 150 amps. Gas models such as the MIZUDO 120K BTU utilize natural gas or propane, bypassing heavy electrical demands. If you lack adequate panel capacity, a gas heater is the practical choice. Verify your fuel source availability before selecting a model, as switching fuels requires professional installation and new line connections. This decision dictates your entire installation path and long-term operating costs.
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Check electrical amperage
Electric tankless heaters demand high amperage from your main panel. The WINTEMP 36kW requires 150 amps, suitable only for homes with 300A service. Smaller electric units like the WINTEMP 18kW need 75 amps. If your panel cannot support these loads, you must upgrade it or choose gas. Always verify your electrical capacity before purchasing. High-wattage units provide higher flow rates but strain older electrical systems. Ensuring your panel can handle the load prevents tripped breakers and ensures safe, consistent operation for your household needs.
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Assess flow rate needs
Flow rate determines how many fixtures can run simultaneously. Large households need high GPM units like the Rheem RTG, which delivers 9.5 GPM. Smaller homes or single-sink applications can use lower flow models like the Electrolux 14 kW, offering 3.4 GPM. Match the GPM to your peak usage. If you run multiple showers, choose a high-flow gas or electric unit. For a single bathroom, a lower GPM model suffices. This spec directly impacts your comfort and water availability during busy morning routines.
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Determine installation location
Choose between indoor and outdoor placement based on climate and space. Indoor units like the Rheem RTGH require venting and protected environments. Outdoor models like the Rheem RTG Outdoor series withstand weather but need exterior gas connections. The MIZUDO 120K BTU supports both indoor and outdoor use, offering flexibility. Consider your local climate and available wall space. Indoor installations may require additional venting materials, while outdoor units save interior space but need weatherproofing. Select the location that fits your home’s layout and local codes.
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Evaluate venting requirements
Gas tankless heaters require specific venting types. Non-condensing models like the Rheem RTG use standard metal vents, which are simpler to install but less efficient. Condensing units like the Rheem RTGH offer higher efficiency but require direct venting systems. The venting type affects installation complexity and cost. Check your home’s existing venting infrastructure before buying. Indoor installations often need complex venting routes, while outdoor units may have simpler exhaust paths. Proper venting ensures safety and optimal performance, so verify this spec matches your home’s capabilities.
Frequently asked questions
Can I control my tankless water heater remotely with an app?
Yes, models with WiFi allow remote app control. The WINTEMP 36kW lets you monitor usage from your phone. The Westinghouse 24kW adds voice-enabled operation. You can adjust settings or track energy use without being near the unit. This feature is standard on all listed smart models.
Do all WiFi tankless heaters require a specific electrical service?
Electric models have strict electrical requirements. The WINTEMP 36kW needs a 150A service, suitable only for large homes. The Westinghouse 18kW and WINTEMP 18kW both require 75A. Gas models like the MIZUDO 120K BTU avoid high amperage demands. Always verify your panel capacity before choosing an electric unit.
Which WiFi water heater offers the highest flow rate?
The Rheem RTG 9.5 GPM Natural Gas Water Heater provides the highest flow rate at 9.5 GPM. It delivers 199,900 BTU/hr for large households. The WINTEMP 36kW Electric model follows with 8.7 GPM. These high-flow options support multiple simultaneous showers in large homes.
Are there outdoor-capable tankless heaters with WiFi?
Yes, some models support outdoor installation. The Rheem RTG 9.5 GPM Outdoor Natural Gas Water Heater is designed for exterior mounting. It uses non-condensing venting and requires outdoor gas connections. The MIZUDO 120K BTU also fits indoor and outdoor placement. These units save indoor space while maintaining smart connectivity.
What is the smallest WiFi tankless heater available?
The Westinghouse 8kW Smart WiFi Tankless Water Heater is the most compact option. It measures 2.48 inches wide and 8.07 inches tall. It targets single sink applications. The Electrolux 14 kW is also small at 8.9 inches wide. These units fit tight spaces like under-sink cabinets.
Can I use propane with a WiFi-enabled tankless heater?
Yes, several models support propane fuel. The Rheem RTG 9.5 GPM Outdoor Propane Tankless Heater delivers 199,900 BTU output. The Rheem RTGH 9.5 GPM Propane model offers indoor installation with 0.93 UEF efficiency. The Rheem RTG Series 7.0 GPM Propane unit provides 160,000 BTU/hr for indoor multi-fixture homes.
Does WiFi control add voice command capabilities?
Some models include voice-enabled operation. The Westinghouse 24kW Electric WiFi Tankless Water Heater supports smart voice commands. This allows hands-free adjustment of water temperature or monitoring of usage. Other models like the WINTEMP 36kW focus on app control. Check the features list for voice compatibility before purchasing.