Best 24 kW Tankless Water Heaters: 13 Spec-Based Picks
As an Amazon Associate we earn from qualifying purchases. Links on this page are affiliate links.
Selecting the best 24 kW tankless water heaters requires careful attention to electrical capacity and flow rate. We compared 13 models based strictly on published specifications to help you find a unit that matches your home’s power infrastructure. Our top pick, the Rheem 24 kW Electric Tankless Water Heater, leads because it delivers up to 5.9 GPM with a design that supports whole-home demand on a 200-amp panel. This guide helps you decide which heater fits your specific electrical and spatial needs.
Quick picks
The best fit for you
- You need whole-home heating with a 200-amp electrical panel Rheem 24 kW Electric Tankless Water Heater It delivers 5.9 GPM and requires three 40-amp breakers for whole-house use.
- You want the most compact unit with the thinnest profile Camplux 24 kW Electric Tankless Water Heater This model features a slim 3.12-inch depth for tight wall spaces.
- You require smart home integration with WiFi connectivity Westinghouse 24kW WiFi Tankless Water Heater It includes integrated WiFi for mobile and voice control alongside 5.55 GPM flow.
- You need a portable propane option for outdoor camping SHENGJINSH 12L Portable Propane Water Heater This propane unit offers portability and 3.2 GPM flow without electrical hookups.
Our 13 picks
Rheem 24 kW Electric Tankless Water Heater
Best for: whole-home use with a 200-amp panel
- Wattage
- 24 kW (what this guide is about)
- Flow Rate
- 5.9 GPM
- Voltage
- 240 V
- Temperature Control
- 80°F - 140°F, 1-degree increments
- Dimensions
- 14.5 in W x 18.3 in L x 3.5 in H
- Fuel Type
- Electric
This Rheem unit is a whole-house electric tankless water heater that runs on 240 volts and draws 24 kW. It delivers a maximum flow rate of 5.9 GPM to serve multiple fixtures simultaneously without storage standby losses. You get digital temperature controls adjustable in 1-degree steps from 80°F to 140°F. It suits your home if you have a 200-amp electrical service panel and need steady, vent-free hot water.
Pros
- Flow rate up to 5.9 GPM for multiple fixture use
- Digital thermostatic controls in 1-degree increments from 80°F to 140°F
- Operates without venting
- Compact depth of 3.5 inches
Cons
- Requires three 40-amp double-pole breakers
- Requires a minimum 200-amp household electrical service panel
- Needs three sets of 8 AWG copper conductors
Good fit if
- You have a 200-amp electrical panel that can fit three 40-amp double-pole breakers.
- You need up to 5.9 GPM for multiple fixtures at once.
- You want digital temperature adjustments in 1-degree increments.
Skip if
- You have an electrical service panel rated below 200 amps.
- You cannot accommodate three separate runs of 8 AWG copper wiring.
Verdict: Rheem 24 kW Electric Tankless Water Heater delivers up to 5.9 GPM with single-degree digital temperature control for whole-home demand. It is a practical, vent-free option if your electrical service can support three 40-amp breakers.
Thermomate 24 kW Electric Tankless Water Heater
Best for: high-flow indoor whole-home electric water heating
- Wattage
- 24 kW (what this guide is about)
- Fuel Type
- Electric
- Flow Rate
- Up to 5.90 GPM
- Installation Location
- Indoor
- Voltage
- 240 Volts
- Temperature Control
- 80°F to 140°F, 1° increments
View on Amazon: Thermomate 24 kW Electric Tankless Water Heater
This Thermomate unit delivers 24 kW of electric heating power on a 240-volt connection, supplying up to 5.90 GPM of continuous hot water. You adjust output with a front dial in precise one-degree increments from 80°F to 140°F, while self-modulating technology balances energy draw. At 16.9 inches tall and 13 inches wide, it suits indoor setups where you need multi-fixture capacity without dedicating floor space to a tank.
Pros
- Up to 5.90 GPM maximum flow rate
- Precise temperature settings from 80°F to 140°F in 1° increments
- Self-modulating power regulation
- Automatic heating shutoff when no water is detected
Cons
- Rated strictly for indoor installation
- No remote control or wireless connectivity listed
Good fit if
- You need up to 5.90 GPM of continuous hot water for indoor fixtures.
- You want precise 1-degree temperature tuning via a front dial.
- You have a dedicated 240-volt electrical service ready for 24 kW.
Skip if
- You need an outdoor-rated water heater.
- You require wireless monitoring or mobile app control.
Verdict: Thermomate 24 kW Electric Tankless Water Heater pairs a 5.90 GPM maximum flow rate with precise single-degree dial adjustments for indoor 240V installations. It gives you dependable, self-modulating output without consuming valuable floor space.
Stiebel Eltron Tempra 24 Trend Water Heater
Best for: whole-house electric heating with copper elements
- Wattage
- 24 kW (what this guide is about)
- Fuel Type
- Electric
- Voltage
- 240 V
- Temperature Control
- 68° to 140°F
- Dimensions
- 14.5 x 16.6 x 4.63 in
- Use
- Whole House
The Stiebel Eltron Tempra 24 Trend is an electric tankless water heater engineered for whole-house use. Operating at 24 kW and 240V, it requires a 150 A minimum electrical service panel. You get an output temperature range from 68°F to 140°F, controlled via a front digital display. Inside, solid copper heating elements deliver silent, on-demand hot water without venting. It fits homes needing high-draw electric heating with precise digital temperature management.
Pros
- Solid copper interior heating system
- Wide 68°F to 140°F digital temperature range
- 7-year leakage and 3-year parts warranty coverage
- Requires no venting and operates silently
Cons
- Demands a 150 A minimum electrical service
- No remote control or Wi-Fi connectivity listed
Good fit if
- You have an electrical panel with at least 150 A service.
- You want an internal copper heating system with digital display control.
- You need output temperatures adjustable up to 140°F without exterior venting.
Skip if
- You lack the 150 A electrical service capacity required for installation.
- You want built-in Wi-Fi or smartphone control.
Verdict: Stiebel Eltron Tempra 24 Trend Water Heater delivers reliable 24 kW electric heating with solid copper elements and wide digital temperature adjustment. It provides quiet whole-house hot water provided your electrical system supports its 150 A demand.
Westinghouse 24kW WiFi Tankless Water Heater
Best for: smart homes needing connected whole-house heating
- Wattage
- 24 kW (what this guide is about)
- Fuel Type
- Electric
- Flow Rate
- 5.55 GPM
- Voltage
- 240V
- Temperature Control
- 86-140℉
- Certification
- ETL
View on Amazon: Westinghouse 24kW WiFi Tankless Water Heater
This 24 kW electric unit delivers up to 5.55 GPM of continuous hot water for whole-home use on a 240-volt system. It features built-in Wi-Fi for remote adjustments via an app or voice commands through Alexa and Google Home. If you have 100 amps of electrical capacity across three 40-amp double-pole breakers, this compact wall-mounted heater suits apartments and homes running multiple fixtures.
Pros
- Maximum flow rate of 5.55 GPM
- Smart Wi-Fi connectivity with Alexa and Google Home voice control
- Compact wall-mount footprint measuring 17.1 by 13 by 4.3 inches
- Standard 3/4-inch NPT bottom water connections
Cons
- Requires 100A electrical service with three 40A double-pole breakers
- Minimum starting flow rate requires 0.79 GPM to activate
Good fit if
- You want remote temperature and usage monitoring through Wi-Fi or voice controls.
- You have panel capacity for three 40-amp double-pole breakers and 8 AWG wiring.
- You need up to 5.55 GPM flow for running a sink and shower simultaneously.
Skip if
- You need heating activation at flow rates lower than 0.79 GPM.
- You lack the electrical capacity to dedicate 100 amps to water heating.
Verdict: Westinghouse 24kW Smart Wi-Fi Tankless Water Heater pairs a 5.55 GPM maximum flow rate with integrated voice and mobile controls for connected homes. Its three-breaker electrical requirement delivers reliable whole-house output in a compact wall-hung frame.
SIVUATEK 24 kW Point-of-Use Tankless Water Heater
Best for: point-of-use high-demand electric water heating
- Wattage
- 24 kW (what this guide is about)
- Fuel Type
- Electric
- Voltage
- 240V
- Certification
- ETL
- Dimensions
- 17.3 x 12.2 x 12.2 inches
- Use
- Whole House
View on Amazon: SIVUATEK 24 kW Point-of-Use Tankless Water Heater
This SIVUATEK unit is a 24 kW, 240V electric tankless water heater designed for point-of-use placement near fixtures like showers or washing machines. It features standard 3/4-inch NPT pipe connections and an isolated heating chamber separating water and electrical lines. If you need dedicated high-output heating close to your taps, this heater delivers self-modulating power requiring three 40A double-pole breakers and 8 AWG wiring.
Pros
- Separated water and electricity lines inside heating chamber
- Standard 3/4-inch NPT water connections
- Self-modulating power adjustment based on flow rate and temperature
- Built-in leakage, dry-heating, and high-temperature shutoff protections
Cons
- Requires three 40A double-pole breakers and three 8 AWG wire runs
- Deep 12.2-inch profile requires significant enclosure space
- No remote control or wireless connectivity listed
Good fit if
- You want a dedicated 24 kW electric heater positioned near high-demand fixtures.
- You have panel space for three 40A double-pole breakers and 8 AWG wiring.
Skip if
- You lack electrical capacity for three dedicated 40A double-pole circuits.
- You need a slim profile under 12 inches deep for tight under-sink spaces.
Verdict: SIVUATEK 24 kW Point-of-Use Tankless Water Heater delivers high-capacity, self-modulating electric heating directly near fixtures using standard 3/4-inch NPT fittings. Its demanding electrical requirement means you must verify your panel capacity before installation.
Camplux 24 kW Electric Tankless Water Heater
Best for: compact electric whole-home installations
- Wattage
- 24 kW (what this guide is about)
- Fuel Type
- Electric
- Voltage
- 240 Volt
- Temperature Control
- 80℉ to 140℉
- Certification
- ETL
- Dimensions
- 17.12 x 13.12 x 3.12 inches
View on Amazon: Camplux 24 kW Electric Tankless Water Heater
This 24 kW, 240-volt electric tankless water heater delivers on-demand hot water using heating elements separated from the water pipe. You can set the digital display anywhere from 80°F to 140°F, while heating activates at a minimum flow rate of 0.66 GPM. Its 3.12-inch slim profile fits tight wall spaces, making it a practical option if your electrical panel supports three 8 AWG wire runs.
Pros
- Adjustable temperature range from 80°F to 140°F
- Low activation flow rate of 0.66 GPM
- Compact 3.12-inch depth for tight wall spaces
- Digital temperature display with heating indicator light
- Built-in overheating and anti-dry heating protection
Cons
- Requires three 8 AWG wire runs and 240V electrical service
- No remote control or wireless connectivity listed
- Requires separate valve kit for recommended installation
Good fit if
- You want a compact electric unit with a 3.12-inch depth profile.
- You need an output water temperature between 80°F and 140°F.
- You have plumbing fixtures running at or above 0.66 GPM.
Skip if
- You need fixtures running below 0.66 GPM to trigger heating.
- You want app-based monitoring or remote control features.
- Your electrical service panel cannot support three 8 AWG circuits.
Verdict: Camplux 24 kW Electric Tankless Water Heater provides digital temperature control up to 140°F in a compact, 3.12-inch deep chassis. It fits standard household heating demands if your electrical service supports three 8 AWG wire runs.
Fogatti 24 kW Electric Tankless Water Heater
Best for: whole-home setups needing single-degree temperature adjustments
- Wattage
- 24 kW (what this guide is about)
- Fuel Type
- Electric
- Flow Rate
- 6.0 GPM
- Voltage
- 240V
- Temperature Control
- 86–140°F, 1°F increments
- Certification
- ETL
View on Amazon: Fogatti 24 kW Electric Tankless Water Heater
This 24 kW, 240-volt electric tankless water heater delivers up to 6.0 GPM flow at a 77°F inlet temperature for whole-house use. You get an LED display with knob adjustments spanning 86°F to 140°F in 1°F increments. A 0.5 GPM minimum activation flow turns on heating. At 17.1 by 12.9 by 3.9 inches, this wall-mounted unit suits homes seeking precise temperature settings in tight utility spaces.
Pros
- Delivers up to 6.0 GPM flow rate with a 77°F inlet temperature
- Temperature range of 86°F to 140°F adjustable in 1°F increments
- Compact wall-mount footprint measuring 17.1 x 12.9 x 3.9 inches
- Features LED display with manual knob control
Cons
- Requires a minimum water flow of 0.5 GPM to activate heating
- Max 6.0 GPM flow depends on a warm 77°F inlet water temperature
Good fit if
- You need precise single-degree temperature settings between 86°F and 140°F.
- You have limited space and need a slim 3.9-inch deep wall-mounted profile.
Skip if
- You draw low flow rates under the 0.5 GPM activation threshold.
- You expect 6.0 GPM in cold climates where inlet water is far below 77°F.
Verdict: Fogatti 24 kW Electric Tankless Water Heater delivers up to 6.0 GPM with single-degree control from 86°F to 140°F. Its slim 3.9-inch profile fits tight wall spaces when connected to a 240V electric supply.
Westinghouse 24kW 240V Wi-Fi Tankless Water Heater
Best for: smart home integration and precise temperature adjustments
- Wattage
- 24 kW (what this guide is about)
- Fuel Type
- Electric
- Flow Rate
- 0.5–5.6 GPM
- Voltage
- 240 V
- Temperature Control
- 86–140°F, 1°F increments
- Certification
- ETL
View on Amazon: Westinghouse 24kW 240V Wi-Fi Tankless Water Heater
This Westinghouse unit provides 24 kW of on-demand heating for whole-house use. Operating at 240V and drawing 100A, it delivers between 3.5 GPM with 57°F incoming water and 5.6 GPM with 77°F water. It pairs a digital LED interface with Wi-Fi integration for Alexa and Google Home adjustments. You can set the water temperature between 86°F and 140°F in single-degree steps, fitting tight installations with its 3.94-inch depth.
Pros
- Wi-Fi connectivity with Alexa and Google Home integration
- Flow rate reaches up to 5.6 GPM at 77°F inlet temperature
- Adjustable temperature range from 86°F to 140°F in 1°F increments
- Includes scale inhibitor with built-in leak and dry-fire protection
Cons
- Flow drops to 3.5 GPM with colder 57°F inlet water
- Requires a 100A electrical service dedicated at 240V
Good fit if
- You want smart home controls via Wi-Fi, Alexa, or Google Home.
- You have an electrical setup capable of supplying 240V and 100A.
- You need precise temperature adjustments in 1°F increments.
Skip if
- You live in cold climates and require more than 3.5 GPM output.
- You do not have 100A of electrical panel capacity available.
Verdict: Westinghouse 24 kW Smart Electric Tankless Water Heater delivers precise single-degree temperature settings and smart home integration if your panel supports a 100A draw.
Atmor 24kW 4.7 GPM Tankless Water Heater
Best for: moderate-climate homes with up to two bathrooms
- Wattage
- 24 kW (what this guide is about)
- Fuel Type
- Electric
- Flow Rate
- 4.7 GPM
- Temperature Control
- 90°F–125°F, 1°F increments
- Certification
- cETL
- Dimensions
- 18.9 x 4.49 x 14.3 inches
The Atmor 24kW 4.7 GPM Tankless Water Heater is an electric unit designed for whole-home use. It features a 0.99 UEF efficiency rating and digital temperature control from 90°F to 125°F in 1°F increments. It suits you if you need to supply up to two bathrooms in warmer climates, or 1 to 1.5 bathrooms in cooler regions.
Pros
- Energy-efficient 0.99 UEF rating
- Adjustable temperature from 90°F to 125°F in 1°F increments
- Stainless steel internal components with dual safety thermal cutoff
- Standard 3/4-inch NPT fittings for plumbing connections
Cons
- Maximum temperature setting is limited to 125°F
- Requires three 40-amp double-pole breakers and 8/2 AWG wiring
Good fit if
- You have electrical capacity for three 40-amp double-pole breakers.
- You need to supply one to two bathrooms depending on regional climate.
- You want digital temperature adjustment dialed in by single degrees.
Skip if
- You require water temperatures exceeding 125°F.
- You live in a cold region and must run multiple high-flow fixtures at once.
- You cannot accommodate three dedicated 240V circuits in your breaker box.
Verdict: Atmor 24kW 4.7 GPM Tankless Water Heater provides precise single-degree temperature adjustments and a 0.99 UEF rating. It offers reliable flow for up to two bathrooms if your electrical panel can support three dedicated 40-amp breakers.
MRNIU 24 kW Electric Tankless Water Heater
Best for: compact 240V electric whole-house installations
- Wattage
- 24 kW (what this guide is about)
- Fuel Type
- Electric
- Voltage
- 240V
- Dimensions
- 17.7 x 13.1 x 13.1 inches
- Use
- Whole House
- Weight
- 14.2 pounds
The MRNIU 24 kW Electric Tankless Water Heater is a 240V whole-house electric unit designed for on-demand hot water. Operating at 24,000 watts, it features an integrated LED temperature display, automatic shut-off, and built-in overheat protection. At 14.2 pounds, this compact wall-mounted unit fits into tight utility spaces where traditional tanks cannot. It suits you if you need steady electric heating for domestic sinks and showers.
Pros
- 24 kW heating capacity on a 240V electrical connection
- Built-in LED digital temperature display
- Safety features include overheat protection and automatic shut-off
- Lightweight 14.2-pound wall-mount design
Cons
- No maximum flow rate (GPM) specified in manufacturer data
- 13.1-inch depth extends farther from the wall than slimmer units
- No remote control or wireless connectivity listed
Good fit if
- You have a dedicated 240V electrical service setup ready for a 24 kW load.
- You need a lightweight, wall-hung unit with visual LED temperature readouts.
- You want whole-house on-demand heating to replace a conventional tank.
Skip if
- You require verified GPM flow-rate ratings before planning your plumbing layout.
- You want smart features, mobile app controls, or a remote interface.
- You need a flat, ultra-shallow profile to fit inside narrow wall clearances.
Verdict: MRNIU 24 kW Electric Tankless Water Heater delivers 24,000 watts of on-demand heating in a lightweight 14.2-pound wall-mount enclosure. It provides digital monitoring and essential safety shut-offs for 240V setups, though published flow rate data is absent.
SHENGJINSH 12L Portable Propane Water Heater
Best for: outdoor camping and off-grid cabin setups
- Wattage
- 24 kW (what this guide is about)
- Fuel Type
- Propane
- Flow Rate
- 3.2 GPM
- Installation Location
- Outdoor
- Certification
- CE, RoHS
- Dimensions
- 23.2 x 14 x 5.9 in
View on Amazon: SHENGJINSH 12L Portable Propane Water Heater
The SHENGJINSH 12L is a 24 kW outdoor tankless water heater fueled by liquid propane rather than electricity. It delivers a maximum flow rate of 3.2 GPM and features automatic ignition, an integrated digital temperature display, and a 20-minute safety shutdown timer. At 13.9 pounds, this compact unit suits you if you need portable off-grid hot water for remote cabins, campsites, or outdoor washing setups.
Pros
- Delivers up to 3.2 GPM using propane fuel
- Lightweight 13.9-pound build designed for portable outdoor use
- Automatic shutoff triggers above 140 °F and after 20 minutes
- Digital display provides real-time outlet water temperature
Cons
- Restricted to outdoor installation only
- Lower 3.2 GPM capacity than standard whole-house units
Good fit if
- You need an outdoor, propane-fueled 24 kW water heater for off-grid or campsite use.
- You want a lightweight, portable setup weighing under 14 pounds.
Skip if
- You need an indoor unit for permanent whole-house residential plumbing.
- You prefer a hardwired electric 24 kW water heater.
Verdict: SHENGJINSH 12L Portable Propane Water Heater stands out as the propane-powered option in this 24 kW class, offering genuine portability for outdoor and cabin setups. Its 3.2 GPM flow rate and compact footprint make it a practical pick when electrical hookups are unavailable.
Eemax 24 kW Electric Tankless Water Heater
Best for: homes wired for 240V high-capacity electric heating
- Wattage
- 24 kW (what this guide is about)
- Voltage
- 240 V
- Fuel Type
- Electric
This Eemax unit is an electric tankless water heater designed to provide hot water on demand. It operates on a dedicated 240-volt electrical supply and provides 24 kW of heating power. If your home has the electrical capacity to support a 240V, 24 kW appliance, this model provides full electric heating without a storage tank taking up space. It suits you if you need a high-power electric setup.
Pros
- 24 kW heating capacity for on-demand hot water
- Runs on standard 240-volt electrical service
- Tankless electric design eliminates standing water storage
Cons
- Flow rate and GPM ratings are not specified in the listing
- No display or smart controls listed in the product specifications
Good fit if
- You have an electrical panel that supports a 240V, 24 kW load.
- You prefer an all-electric tankless heating configuration.
Skip if
- You require verified flow rate ratings before purchasing.
- You need gas or propane water heating instead of electric.
Verdict: Eemax 24 kW Electric Tankless Water Heater delivers 24 kW of on-demand heating across a 240V electrical connection. It offers a straightforward electric design for homes equipped for its power requirements.
Stiebel Eltron Tempra 24 Tankless Water Heater
Best for: vent-free whole-house 240V electric heating
- Wattage
- 24 kW (what this guide is about)
- Fuel Type
- Electric
- Voltage
- 240 V
- Dimensions
- 14.5 x 4.61 x 16.5 in
- Use
- Whole House
- Weight
- 16.1 pounds
View on Amazon: Stiebel Eltron Tempra 24 Tankless Water Heater
The Stiebel Eltron Tempra 24 is an electric tankless water heater designed for whole-house use. Operating at 240V and delivering 24 kW of heating capacity, this unit measures 14.5 by 16.5 by 4.61 inches and weighs 16.1 pounds. It requires no venting during setup, which simplifies installation across various indoor spaces. You get a compact profile built to support standard residential demand without bulky storage tanks.
Pros
- Operates at 24 kW on 240V power
- Requires no venting
- Shallow 4.61-inch depth fits tight wall spaces
- Lightweight 16.1-pound chassis
Cons
- Style options list this unit as a discontinued model
- No wireless connectivity included in the specifications
Good fit if
- You need a 24 kW, 240V system for whole-house demands.
- You want a tankless heater that requires no venting.
- You have limited wall clearance and need a 4.61-inch depth.
Skip if
- You cannot provide a 240V electrical connection.
- You prefer a current model line rather than a discontinued variation.
Verdict: Stiebel Eltron Tempra 24 Tankless Water Heater delivers 24 kW of electric power in a 16.1-pound, vent-free package. It fits whole-house installations configured for 240V connections.
Specifications side by side
| Spec | Rheem 24 kW Electric Tankless Water Heater | Thermomate 24 kW Electric Tankless Water Heater | Stiebel Eltron Tempra 24 Trend Water Heater | Westinghouse 24kW WiFi Tankless Water Heater | SIVUATEK 24 kW Point-of-Use Tankless Water Heater | Camplux 24 kW Electric Tankless Water Heater | Fogatti 24 kW Electric Tankless Water Heater | Westinghouse 24kW 240V Wi-Fi Tankless Water Heater | Atmor 24kW 4.7 GPM Tankless Water Heater | MRNIU 24 kW Electric Tankless Water Heater | SHENGJINSH 12L Portable Propane Water Heater | Eemax 24 kW Electric Tankless Water Heater | Stiebel Eltron Tempra 24 Tankless Water Heater |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Fuel Type | not specified | Electric | Electric | Electric | Electric | Electric | Electric | Electric | Electric | Electric | Propane | not specified | Electric |
| Flow Rate | 5.9 GPM | Up to 5.90 GPM | not specified | 5.55 GPM | not specified | not specified | 6.0 GPM | 0.5–5.6 GPM | 4.7 GPM | not specified | 3.2 GPM | not specified | not specified |
| Wattage | 24 kW | 24kW | 24 kW | 24kW | 24 kW | 24kW | 24kW | 24 kW | 24kW | 24Kw | not specified | 24 kW | 24 kW |
| Installation Location | not specified | Indoor | not specified | not specified | not specified | not specified | not specified | not specified | not specified | not specified | Outdoor | not specified | not specified |
| Voltage | 240 V | 240 Volts | 240 V | 240V | 240V | 240 Volt | 240V | 240 V | not specified | 240V | not specified | 240 V | 240 V |
| Temperature Control | 80°F - 140°F, 1-degree increments | 80°F to 140°F, 1° increments | 68° to 140°F | 86-140℉ | not specified | 80℉ to 140℉ | 86–140°F, 1°F increments | 86–140°F, 1°F increments | 90°F–125°F, 1°F increments | not specified | not specified | not specified | not specified |
| Certification | not specified | ETL | not specified | ETL | ETL | ETL | ETL | ETL | cETL | not specified | CE, RoHS | not specified | not specified |
| Dimensions | 14.5 in W x 18.3 in L x 3.5 in H | 33.3W x 43.5H Centimetres | 14.5 x 16.6 x 4.63 in | 17" H × 13" W × 4.3" D | 17.3 x 12.2 x 12.2 inches | 17.12 x 13.12 x 3.12 inches | 17.1 x 12.9 x 3.9 inches | 18.7 x 14.17 x 3.94 in | 18.9 x 4.49 x 14.3 inches | 17.7 x 13.1 x 13.1 inches | 23.2 x 14 x 5.9 in | not specified | 14.5 x 4.61 x 16.5 in |
| Use | Whole House | not specified | Whole House | Whole House | Whole House | not specified | Whole House | Whole House | not specified | Whole House | Camping, Cabins | not specified | Whole House |
| Features | not specified | not specified | not specified | WiFi | not specified | Digital Display | not specified | WiFi | not specified | not specified | Digital Display, Overheat Protection | not specified | not specified |
| Weight | 17.8 pounds | not specified | 16.1 pounds | 17 pounds | 20 pounds | 20.3 pounds | not specified | not specified | 15.1 pounds | 14.2 pounds | not specified | not specified | 16.1 pounds |
| Color | Gray | Gray | White | Gray 24 | Black | White | Gray 24 | Gray 24 | Gray | White | Gray | not specified | not specified |
| Model | RTEX-24 | ET240 | 24 Trend | WET-24K-G | V7B-240B | TEW24-CA | ET24 | ET024CA0G | AT-24N-XTP | Mrniu24 | 12L | HA024240 | Tempra 24 |
| Size | not specified | not specified | 24 (kW) | L-24 | L-24 | 240V/24kW | L-24 | L-24 | 4.7 GPM | not specified | not specified | not specified | 24 |
Is 24 kW Worth the Electrical Upgrade?
Twenty-four kilowatts delivers high flow rates, typically between 4.7 and 6.0 gallons per minute, for whole-home hot water. This power level supports simultaneous use in multiple bathrooms. Most electric models require a 240V supply and three dedicated 40-amp breakers. The SHENGJINSH propane unit is the only exception, offering portability without high electrical demand. This wattage ensures consistent temperature control, often down to single-degree adjustments, even under heavy load.
Worth it if
- You need whole-home hot water for multiple bathrooms.
- Your electrical panel supports three 40-amp breakers or a 100-amp service.
- You want precise digital temperature control for consistent shower comfort.
Skip it if
- You only need point-of-use heating for a single sink.
- Your home lacks the required 240V electrical capacity.
- You are installing in an off-grid cabin without grid power.
If you are also comparing home fitness gear, you can evaluate the best water rowers using similar mechanical specifications.
How We Selected 24 kW Models
We gathered these units by scanning Amazon listings that explicitly list 24 kW wattage in the title or feature list. We include only one variant per product family to keep the comparison clean. All details come from published specifications, not physical testing. You can trust that each entry meets this specific power threshold.
The list is ordered by availability first, followed by overall rating weighted by review count. We then apply our criteria to rank the remaining options. This method ensures you see the most relevant and highly rated 24 kW electric and propane models first, helping you find the right fit for your home's electrical capacity.
Key Specs for Choosing a Unit
-
Check your electrical panel
Most 24 kW electric models require three 40-amp breakers or a 100-amp to 200-amp service. Verify your panel capacity before buying. The Rheem RTEX-24 needs three 40-amp breakers for whole-home use. The Stiebel Eltron Tempra 24 Trend demands up to 150 A. Ensure your home supports the voltage and amperage requirements of your chosen model to avoid tripping circuits or damaging the unit.
-
Match flow rate to usage
Flow rate determines how many fixtures can run simultaneously. The Fogatti ET24 delivers up to 6.0 GPM, supporting high demand. The Atmor AT-24N-XTP provides 4.7 GPM, suitable for up to two bathrooms. The Westinghouse WET-24K-G offers 5.55 GPM. Higher GPM values allow more concurrent use, such as showers and sinks. Check the published GPM to ensure it meets your household’s peak hot water needs.
-
Select the correct fuel type
Fuel type dictates installation requirements and energy source. Most units in this list are electric, requiring 240V connections. The SHENGJINSH 12L is a propane option, ideal for outdoor camping or off-grid cabins. It does not need high-amperage electrical connections. Choose electric for whole-home residential use with proper wiring. Select propane for portable, outdoor, or remote applications where grid power is unavailable or impractical.
-
Verify installation location
Location affects venting and weather exposure. Electric models like the Rheem and Stiebel Eltron are vent-free, allowing indoor installation in closets or utility rooms. The SHENGJINSH propane unit is designed for outdoor use. Ensure your chosen model matches your installation space. Indoor units do not require exhaust vents. Outdoor units must withstand environmental conditions. Check the installation location specifications to prevent improper placement and potential damage.
-
Consider smart home integration
Smart features allow remote control and monitoring. The Westinghouse WET-24K-G includes WiFi connectivity for mobile and voice control. The Westinghouse ET024CA0G also offers smart home integration for precise temperature adjustments. These models let you monitor usage and adjust settings remotely. If you prefer manual control, other models like the Eemax HA024240 lack these features. Choose a WiFi-enabled unit if you want digital management of your hot water system.
Frequently asked questions
Can a 24 kW electric tankless water heater heat my whole house?
Yes, most 24 kW electric models support whole-home use. The Rheem RTEX-24 delivers up to 5.9 GPM for whole-home demand. The Fogatti ET24 also provides up to 6.0 GPM for whole-home setups. These units handle simultaneous hot water needs if your electrical panel supports the required amperage.
What electrical panel size do I need for a 24 kW unit?
Most electric 24 kW heaters require a 200-amp panel or three dedicated 40-amp breakers. The Rheem RTEX-24 needs three 40-amp breakers. The Stiebel Eltron Tempra 24 Trend demands 150 A. The Camplux TEW24-CA requires three 8 AWG wire runs. Always verify your panel capacity before installation.
Which 24 kW tankless heater is the most compact?
The Camplux TEW24-CA is the thinnest at 3.12 inches deep. The Fogatti ET24 has a slim 3.9-inch profile. The Stiebel Eltron Tempra 24 is 4.63 inches deep. These compact designs fit tight wall spaces while delivering 24 kW of heating power for your home.
Is there a propane option in the 24 kW category?
Yes, the SHENGJINSH 12L is a propane-powered unit. It offers 3.2 GPM flow for outdoor camping and cabin setups. It is the only propane option in this list, so it does not need high-amperage electrical connections. It provides genuine portability when electrical hookups are unavailable.
Do any 24 kW heaters have WiFi connectivity?
Yes, two Westinghouse models feature WiFi. The WET-24K-G offers integrated voice and mobile controls. The ET024CA0G also supports smart home integration. Both allow precise temperature adjustments via app. These units deliver reliable whole-house output with connected features for modern homes.
How much hot water can a 24 kW unit provide?
Flow rates typically range from 4.7 to 6.0 gallons per minute. The Fogatti ET24 provides up to 6.0 GPM. The Rheem RTEX-24 delivers up to 5.9 GPM. The Atmor AT-24N-XTP offers 4.7 GPM. Higher flow rates support simultaneous use in multiple bathrooms.
What is the difference between the Stiebel Eltron Tempra 24 models?
The Tempra 24 Trend uses solid copper elements and offers wide digital temperature adjustment. The standard Tempra 24 is a vent-free package weighing 16.1 pounds. Both deliver 24 kW of electric power. The Trend model emphasizes premium elements, while the standard model focuses on basic whole-house heating.