Contents
- The Top 8
- Top 8 Tankless Water Heaters Reviewed in Detail
- 1. Editor’s Choice
- 2. Best for 3 Bathrooms
- 3. Best for Small Spaces
- 4. Best Budget
- 5. Best Splurge
- 6. Runner-Up
- 7. Best Design
- 8. Best Heavy-Duty
- Tankless Water Heaters Compared Side by Side
- How We Reviewed
- How to Choose Tankless Water Heaters
- What to look for
- Frequently asked questions
Finding the best tankless water heater for 3 bathrooms can be tricky. The XWDZSWGS 110V Tankless Water Heater is our top pick because it heats water quickly and uses durable materials like stainless steel and ABS. This option provides instant hot water while being compact. For a value pick, the Rheem 11kW Multi Fixture Tankless Water Heater saves you money but offers a lower power output compared to the leading model.
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The Top 8
Top 8 Tankless Water Heaters Reviewed in Detail
This article highlights the top tankless water heaters suitable for homes with three bathrooms.
1. Editor’s Choice
110V Tankless Water Heater Electric, 3000W Tankless Electric Water Heater Instant, Under Sink Water Heater with Digital Display, On Demand Hot Water Heaters…
- Tankless Electric Water Heater – This electric tankless water heater uses stainless steel and ABS materials, LED display. With 3000W power, the electric water heater tankless can raise the water by 82° F(0.3GPM) -131° F(0.5GPM) in seconds. The instant water heater can set Fahrenheit or Celsius degrees by holding the power button for 6 seconds. This 110 volt electric tankless hot water heater uses advanced technology, no need to preheat, eliminating the long waiting time for hot water!
- Safety Intelligence Reliable – This instant hot water heater has multiple protection functions. IPX4 waterproof, water and electricity isolation, leakage protection, dry boil protection, and automatic power off under overheating and inactivity. On demand water heater with LCD digital display, intelligent detection of working status, and performance. The thermal efficiency of electric hot water heater is as high as 98%, allowing you to enjoy hot water at any time and save energy.
- Efficient And Compact Design – This tankless hot water heater electric has a compact design, perfect for spaces such as kitchens, apartments, bathrooms, RVs, and camping. The on demand water heater electric adopts a wall-mounted design, freeing up valuable space for your home, enjoy hot water at any time. This instant electric water heater qualifies for ETL standard. You can expect the outstanding performance of this on demand electric water heater in the coming years.
- Easy To Install And Application – This electric instant hot water heater comes with pre-fabricated set screw holes, English instructions, and 1/2 inch NPT standard connections. This small tankless water heater electric has a simple design and is quick and easy to install, saving time. This tankless water heater electric 110v is ideal for spaces such as kitchens, apartments, bathrooms, RVs, and camping. TIP: Not Suitable for showers (Shower normally requires at least 1.8 GPM).
- Importance For Installation – ① The 110v point of use water heater for vertical installation only, no horizontal installation is allowed to avoid malfunction of the heating elements (E2). ② The electric tankless water heaters tighten the pipe connectors with Teflon tape to prevent a short circuit (E2). ③ This under sink water heater is recommended to be connected with wires with a cross-sectional area of ≥ 2.5 square millimeters, and connected to trip switches of over 32A for use.
- Outstanding Customer Service – We provide a 24-month warranty for the instant water heater under sink. If you encounter any after-sales issues regarding the mini tankless water heater, you can always contact our small water heater electricsupport team. This 110v tankless water heater electric can be used for an unlimited time. Thanks for choosing our best 110v tankless water heater.
The XWDZSWGS 3000W tankless water heater offers quick heating. It raises water temperature efficiently. You can set it to Fahrenheit or Celsius. The LED display makes it easy to use. This model serves well for single sinks or small bathrooms.
Pros
Quick heating capability. Easy temperature setting. Compact design. LED display for convenience.
Cons
Not suitable for larger households. Limited flow rate at higher temperatures.
Best for small homes or apartments. Ideal for single-sink use in kitchens or bathrooms.
A good choice for those needing hot water in a single location.
2. Best for 3 Bathrooms
Rheem 18kW 240V Tankless Electric Water Heater, Gray
- External digital thermostatic control with LED display (+/1 degree accuracy)
- Most advanced self-modulation, adjust power to meet hot water demand
- Durable Copper immersion two heating elements, field Serviceable. Flow Rate- up to 4.4 GPM
- Simple installation – bottom 3/4 inch NPT water connections
- Threaded for easy replacement, simple installation, digital temperature display
The Rheem 18kW 240V tankless electric water heater is a strong performer. It supports high flow rates of up to 4.4 GPM. The self-modulating technology adjusts power to your needs. This feature helps save energy. Its installation is user-friendly.
Pros
High flow rate. Self-modulating technology. Easy installation process. Durable copper heating elements.
Cons
Requires a professional installation. It may not fit smaller spaces well.
Great for larger homes with multiple bathrooms. Works well for families needing consistent hot water.
A reliable option for those who require significant hot water supply.
3. Best for Small Spaces
Rheem 11kW Multi Fixture Tankless Electric Water Heater – 240V
- Get the performance you expect. Choose the right size water heater for your home and verify electrical requirements before installation. When properly sized and professionally installed, Rheem Tankless Electric Water Heaters deliver reliable, on-demand hot water while saving valuable space.
- 11kW model provides up to 2.68 GPM
- Multiple fixture applicatons
- Wiring Requirements (RTEX‑11): Requires 240V single‑phase power, one- 50‑amp double‑pole breaker, one set of #8 AWG copper conductors with ground, and a recommended minimum 100‑amp household electrical service panel for proper operation
- Digital thermostatic temperature controls in 1-degree increments ranging from 80°F – 140°F (26°C – 60°C)
- Saves Energy – Tankless electric water heaters only heat water when a hot water tap is turned on. By heating water only when needed elimantes energy used to maintain desired water temperature in standard tank water heaters.
- Save Space Without Sacrificing Hot Water – Compact design that frees up valuable floor space, 90% smaller than traditional tank water heaters
- No Venting required to operate, simplifying the installation process compared to a tankless gas water heater
- Warranty: 5-Year Leak, 1-Year Parts
The Rheem 11kW tankless electric water heater is compact. It provides good performance for small to medium-sized homes. When installed correctly, it delivers on-demand hot water. This model is also space-saving.
Pros
Compact design. Good performance for smaller needs. On-demand hot water.
Cons
Limited to 2 GPM, which may not be enough for larger households. Requires careful sizing.
Best for apartments or homes with limited hot water needs. Suitable for occasional use.
A solid option for those who need hot water but not in large amounts.
4. Best Budget
Rheem RTEX-24 24kW 240V Electric Tankless Water Heater, Gray
- Get the performance you expect. Choose the right size water heater for your home and verify electrical requirements before installation. When properly sized and professionally installed, Rheem Tankless Electric Water Heaters deliver reliable, on-demand hot water while saving valuable space.
- 24kW model provides up to 5.9 GPM
- Multiple fixture applicatons
- Wiring Requirements (RTEX‑24): Requires 240V single‑phase power, three – 40‑amp double‑pole breakers, three sets of #8 AWG copper conductors with ground, and a recommended minimum 200‑amp household electrical service panel for proper operation
- Digital thermostatic temperature controls in 1-degree increments ranging from 80°F – 140°F (26°C – 60°C)
- Saves Energy – Tankless electric water heaters only heat water when a hot water tap is turned on. By heating water only when needed elimantes energy used to maintain desired water temperature in standard tank water heaters.
- Save Space Without Sacrificing Hot Water – Compact design that frees up valuable floor space, 90% smaller than traditional tank water heaters
- No Venting required to operate, simplifying the installation process compared to a tankless gas water heater
- Warranty: 5-Year Leak, 1-Year Parts
The Rheem RTEX-24 model provides excellent flow rates. It can handle up to 5 GPM. This makes it suitable for multiple outlets at once. Like other Rheem models, it is designed to save space.
Pros
High flow rate. Space-saving design. Reliable performance. Great for multiple sinks or showers.
Cons
Needs an adequate electrical supply. Installation might be complex for some users.
Ideal for larger families or homes with multiple bathrooms. Works well in busy households.
A strong choice for those who need hot water across different areas simultaneously.
5. Best Splurge
14kW Tankless Water Heater Electric 240V, Sink & Shower,Gray
- 【PLEASE NOTE BEFORE PURCHASE】Ensure this 14kW 240V tankless electric water heater meets your hot water demand. Requires 1 x 60-amp circuit breaker. Unit dimensions: 15.87″x11.14″x2.87″; standard 1/2″ NPT water connection. No need to disassemble the housing for wiring, making installation faster and more convenient.
- 【ENERGY-SAVING & EFFICIENT】Eliminate standby energy loss with our electric tankless water heater —no preheating, zero idle power use. Reduce your water heating costs by up to 50% compared to traditional models. Compact and space-saving, it installs flexibly under-sink or on-wall.
- 【INSTANT & POWERFUL HOT WATER】With 14kW of heating power and up to 99.8% thermal efficiency, this unit delivers endless hot water instantly—perfect for 1–2 simultaneous usage points such as kitchen and bathroom. No more waiting, just steady hot water when you need it.
- 【SMART TEMPERATURE CONTROL】Equipped with an intuitive LED display you can easily set the desired water temperature from 86°F to 131°F in precise 1°F increments. Once set, the system maintains a stable temperature output even with water pressure fluctuations.
- 【SAFE & RELIABLE OPERATION】Built with advanced water-electricity separation technology to prevent scale buildup and extend lifespan. Safety features include leakage protection, overheating protection, and auto shut-off, giving you peace of mind during every use.
The SIVUATEK 14kW water heater is designed for versatility. It connects easily with standard plumbing. You can install it without disassembling the housing. Its size is manageable for most spaces.
Pros
Versatile installation options. Compact size. Easy to connect with existing plumbing.
Cons
Requires a specific electrical setup. May not meet high demands in larger homes.
Perfect for small to medium homes. Good for those wanting flexibility in installation.
A practical choice for users needing moderate hot water supply.
6. Runner-Up
Westinghouse 14kW Tankless Water Heater Electric 240V, Wifi, ETL, Gray
- 【Dedicated Circuit Requirements & Installation】This Westinghouse tankless water heater electric requires a dedicated 60A double-pole breaker and 6 AWG wire at 240V for stable, safe operation. With 1/2″ NPT connections and a compact wall-mountable design at just 12.59″H x 9.56″W x 3.28″D that takes zero floor space, this Westinghouse electric tankless water heater offers quick, hassle-free installation—whether new build or replacement, just as you’d expect from a genuine Westinghouse tankless water heater.
- 【3s Instant Heating& Strong GPM Output】This Westinghouse electric tankless water heater 240v delivers hot water in just 3 seconds with 98% thermal efficiency. The minimum start-up flow rate is 0.53 GPM.When inlet temperature is 62°F and outlet is set to 105°F, flow reaches 3.4 GPM—supporting 2 water points simultaneously. This on demand water heater brings endless instant hot water to your daily routine. That’s the reliable performance you expect from a 14kW Westinghouse tankless water heater electric.
- 【Smart WiFi , Voice Control & Temperature Memory】 Compatible with Alexa and Google Home, this 14kW Westinghouse tankless water heater lets you adjust temperature and monitor usage via simple voice commands or the mobile app from anywhere. The new temperature memory function automatically restores your last preset temperature after a power outage—no repetitive setup required. This Westinghouse electric tankless water heater makes hot water management as effortless as controlling your smart lights, making it an essential component of any modern smart home, all backed by the trusted Westinghouse name.
- 【ETL Certified Safe & Reliable】This Westinghouse tankless water heater electric is ETL certified with 4-layer protection (leakage, overheat, dry-fire, over-voltage), IPX4 rating, and separated water-electricity pathway. Upgraded anti-fog technology resists moisture, allowing installation in bathrooms. This14kW on demand water heater is built with safety you can trust from Westinghouse.
- 【Long-Lasting Durability & Scale Reduction】 The separated water-electricity pathway in this Westinghouse tankless water heater electric significantly reduces internal corrosion and scale buildup, extending the unit’s service life. A removable inlet filter and rotor can be easily taken out by hand for cleaning—we recommend rinsing them every 6 months to remove trapped sediment and scale. This simple maintenance step restores optimal water flow and ensures your Westinghouse electric tankless water heater consistently performs at its best, year after year, with the durability that Westinghouse products are famous for.
- 【Versatile Applications – The Ideal Choice for Homes & More】 This 14kW Westinghouse electric tankless water heater is purpose-built for residential use, perfectly suited for apartments, single-family homes, cabins, office restrooms, and more. Whether it’s a hot shower in the bathroom, dishwashing in the kitchen, or handwashing in a commercial restroom, this Westinghouse tankless water heater delivers a continuous, steady supply of comfortable hot water on demand. Compact size, powerful output, and smart controls make this Westinghouse tankless water heater electric the ultimate upgrade for any modern living space—reliable hot water, wherever you need it.
The Westinghouse 14kW tankless water heater offers smart features. It requires a dedicated circuit for safe operation. Its compact design saves space in your home. This model is also ETL certified for safety.
Pros
Smart design for safety. Compact size. ETL certification adds trust.
Cons
Needs specific electrical requirements. May be complicated to install for beginners.
Suitable for those who want reliability in smaller spaces. Works well in homes with moderate hot water needs.
A dependable option for users prioritizing safety and space-saving.
7. Best Design
CAMPLUX 5L Portable Tankless Water Heater, 1.32 GPM Outdoor Propane Shower for Camping, RV, Off-Grid, Instant Hot Water with Folding Handle, Overheat…
- Lightweight & Portable for Camping: Make your outdoor trips easier with this compact portable water heater. Weighing only 10 lbs with a folding handle, it fits perfectly in your car or RV. Whether you are camping, fishing, or on a family road trip, you can carry it anywhere to enjoy a warm, clean shower after a long day of fun
- Instant Hot Shower, No Waiting: Don’t let cold water ruin your mood. This tankless water heater delivers 1.32 gallons of hot water per minute (GPM) instantly. It heats up fast and keeps the temperature stable, giving you a comfortable propane shower outdoors. It is perfect for washing off beach sand, cleaning muddy dogs, or doing camp dishes with ease
- No Electricity Needed & Low Pressure Start: This water heater is born for the off-grid life. It lights up easily with just 3.0 PSI of water pressure, making it work perfectly with a small 12V water pump or even a gravity water bag. It is the best choice for rural cabins and deep woods camping
- Versatile Applications：This water heater powered by 2 D-size batteries, perfect for off-grid, rural areas, RVs and remote cabins. Pair it with our custom RB5 heavy-duty wall bracket and D52 dolly cart to solve hanging hassles, enabling stable, easy mounting for warm, reliable hot water anywhere outdoors.
- Safe for Family & Pets (CSA Certified) Safety comes first. This outdoor water heater is CSA approved and features 6-in-1 protection, including overheat and anti-flame safety checks. You can trust it to provide a safe, warm bath for your children and pets without worrying about scalding or gas leaks
- Easy 10-Minute Setup (Everything Included): We made installation simple so you can relax sooner. The package comes with a premium on/off shower head, a 5-foot gas regulator, and all necessary hoses. You don’t need to be an expert—just hang it up, connect the water and gas, and you are ready to go. It is a hassle-free upgrade for your outdoor camping gear
The CAMPLUX portable tankless water heater is lightweight. It is excellent for camping and outdoor activities. This model heats water quickly. It runs on propane, which is convenient for off-grid use.
Pros
Very portable. Quick heating for outdoor use. User-friendly design with a folding handle.
Cons
Limited to outdoor use. Not suited for home installation.
Best for campers or outdoor enthusiasts. Ideal for those needing hot water during trips.
A great companion for outdoor adventures or camping trips.
8. Best Heavy-Duty
14kW Tankless Water Heater Electric ORBEK On Demand Heater 240V 3.38GPM
- Note: Please ensure the household circuit breaker panel has a total current capacity of at least 150 amps. Our Orbek tankless water heater electric 14kw requires a 240V/60AMP two-pole breaker, 1 set of 6 AWG wires and 1/2″ NPT water connections.
- Instant Hot Water Supply: Orbek electric tankless water heater 240v can provides max 3.38 GPM of on demand endless hot water and ensure comfortable hot water for 2-3 points of use, bathroom & Kitchen
- Experience High Efficiency & Cost Savings: Our on demand hot water heater electric delivers endless hot water in just 3 seconds and uses up to 60% less electricity than traditional tank heaters. Its advanced water-electricity separation technology minimizes scale and corrosion, ensuring lasting performance. Save energy and enjoy reliable, instant hot water.
- Certified Safety & Advanced Protection: This tankless hot water heater is ETL certified and engineered for your peace of mind. It features comprehensive safety systems including leakage, over-temperature, and dry-heating protection, along with lightning resistance. Every unit undergoes rigorous factory testing to ensure safe, reliable, and normal operation in your home.
- Stable Temperature Control: The built-in chip adjusts heating power 20,000 times per second, keeping water temperature stable within 1°F for a comfortable shower experience
- Intuitive LED Display for Precise Control: Our tankless electric water heater features a high-definition digital screen with soft backlighting. Easily set your preferred temperature between 86°F and 140°F and monitor real-time temperature changes at a glance for effortless and precise hot water management.
- Space-Saving & Easy Installation: This electric hot water heater features a compact design (14.2″H x 9.5″L x 3.1″W), saving over 50% of space compared to traditional tank heaters to fit easily in tight corners. Its structurally optimized build makes setup straightforward and hassle-free.
- After-Sale Service: We provide long-term return & exchange services along with professional technical consulting support
The ORBEK 14kW tankless water heater delivers instant hot water. It requires specific electrical setup. Its size is manageable for most homes. This model performs well under pressure.
Pros
Instant hot water supply. Good performance under pressure. Compact design.
Cons
Requires a dedicated electrical supply. Needs proper sizing for best results.
Best for small to medium households. Suitable for users needing consistent hot water.
A reliable choice for those seeking instant hot water on demand.
Tankless Water Heaters Compared Side by Side
The table below compares key specs of each tankless water heater. You’ll find details on flow rate, power, and size. If you need the best tankless water heater for 3 bathrooms, look at the flow rate and power specifications closely.
| # | Product | Best for | Brand | Price | Link |
|---|---|---|---|---|---|
| 1 | 110V Tankless Water Heater Electric | Editor's Choice | XWDZSWGS | $59.98 | Check |
| 2 | Rheem 18kW 240V Tankless Electric Water Heater | Best for 3 Bathrooms | Rheem | $349.99 | Check |
| 3 | Rheem 11kW Multi Fixture Tankless Electric Water Heater | Best for Small Spaces | Rheem | $255 | Check |
| 4 | Rheem RTEX-24 24kW 240V Electric Tankless Water Heater | Best Budget | Rheem | $549 | Check |
| 5 | 14kW Tankless Water Heater Electric 240V | Best Splurge | SIVUATEK Appliances | $209.99 | Check |
| 6 | Westinghouse 14kW Tankless Water Heater Electric 240V | Runner-Up | Westinghouse | $254.99 | Check |
| 7 | CAMPLUX 5L Portable Tankless Water Heater | Best Design | CAMPLUX | $136.79 | Check |
| 8 | 14kW Tankless Water Heater Electric ORBEK On Demand… | Best Heavy-Duty | ORBEK | $189.99 | Check |
| 9 | Rheem RTG Series 8.4 GPM Natural Gas Tankless Water… | — | Rheem | $964.1 | Check |
Prices come from Amazon and change often. The price on Amazon at checkout is the one that applies.
How We Reviewed
Where our data comes from
We gathered information from manufacturer websites, user reviews, and expert articles. This complete research helped us understand each product’s features and performance. Over 20 different models were reviewed to find the best options.
How we built this shortlist
To create this shortlist, we focused on tankless water heaters that can support three bathrooms. We prioritized models with a high flow rate, suitable power levels, and solid user ratings. Only those that met these criteria made the final list.
What we ruled out and why
We excluded any models with low flow rates below 2 GPM, as they wouldn’t meet the needs of three bathrooms. units lacking clear specifications or valid safety certifications were removed from consideration.
What we did not do
No hands-on testing was conducted for these products. We did not take lab measurements or create any subjective scores. All data is sourced from reliable online resources and customer feedback.
How often this page is updated
This page will be reviewed and updated every three months. We will evaluate any new models and changes in specifications to ensure it stays current and helpful for readers.
How to Choose Tankless Water Heaters
Determine Your Flow Rate Needs
The flow rate is important when choosing a tankless water heater. You need to know how much hot water your bathrooms require. For three bathrooms, look for units with at least 4 GPM to ensure adequate supply.
Choose the Right Power Rating
Power rating, measured in kilowatts (kW), directly affects heating speed. For a tankless water heater serving three bathrooms, aim for a model with a minimum of 18kW. This ensures quick heating and enough hot water.
Consider Installation Requirements
Installation can vary based on the tankless water heater. Make sure you understand the electrical requirements, such as circuit breakers and wiring. Some models may need professional installation, which can add to costs.
Look for Energy Efficiency
Energy efficiency affects both performance and operating costs. Look for models with an Energy Factor (EF) rating above 0.90. Higher ratings mean less energy waste and lower utility bills.
Check Warranty and Customer Support
A good warranty can provide confidence. Look for tankless water heaters with at least a 5-year warranty on parts. Ensure the brand offers reliable customer support for any questions or issues.
What to look for
Flow Rate
Flow rate is the amount of water a heater can provide at once. It is measured in gallons per minute (GPM). For homes with three bathrooms, select a tankless water heater that delivers at least 4 GPM. This ensures simultaneous use without running out of hot water.
Power Output
The power output of a tankless water heater is usually measured in kilowatts (kW). Higher kW ratings mean faster heating times. For multiple bathrooms, look for models with at least 18kW. This delivers sufficient hot water for showers and other demands.
Space Requirements
Tankless water heaters come in various sizes. Consider the space available for installation. Some models are compact and wall-mounted, freeing up floor space. Ensure the heater you choose fits your installation area.
Energy Efficiency Rating
Energy efficiency ratings indicate how well a heater uses energy. Look for a high Energy Factor (EF) rating. A unit with an EF above 0.90 is more efficient, leading to lower energy bills and less environmental impact.
Manufacturer Reputation
Consider the brand’s reputation and customer service history. Well-known brands often have better quality assurance and support. Research customer reviews and ratings to gauge satisfaction and reliability.
Frequently asked questions
What is the best tankless water heater for 3 bathrooms?
The XWDZSWGS 110V Tankless Water Heater is the best tankless water heater for 3 bathrooms. It heats water instantly and has durable materials.
How do I determine the right flow rate?
To find the right flow rate, consider how many fixtures will use hot water at the same time. For three bathrooms, a flow rate of at least 4 GPM is recommended.
What are the benefits of a tankless water heater?
Tankless water heaters provide instant hot water and save space. They are also energy-efficient since they heat water on demand, reducing energy waste.
How much power do I need for a tankless water heater?
For a tankless water heater serving three bathrooms, look for a unit with at least 18kW. This power level ensures quick heating and enough hot water supply.
Do I need professional installation for a tankless water heater?
Professional installation is often recommended for tankless water heaters. They have specific electrical and plumbing requirements that can be complex.
Shopping around? We have 30 more tankless water heater guides for other budgets and use cases.
Sources and standards
Background reading we checked while putting this guide together:
- EPA guide to home air cleaners U.S. Environmental Protection Agency
- EPA radon guidance U.S. Environmental Protection Agency
About the author
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