The best tankless water heater for shower use delivers an endless supply of hot water on demand, perfect for busy households. When selecting one, consider factors like flow rate, energy source (gas or electric), and desired temperature rise to ensure consistent performance. Choosing the wrong unit can lead to lukewarm showers, insufficient hot water during peak demand, and wasted energy, ultimately costing you more in the long run.
With numerous models available, pinpointing the ideal tankless water heater requires careful evaluation of your home’s specific needs. Explore our curated list of the top 10 options to find the perfect fit for your daily routine and enjoy reliable hot water.
For consistent hot water on demand, the best tankless water heater for shower use often relies on electric models with sufficient wattage and flow rate, such as the EcoSmart ECO 11 Electric Tankless Water Heater. Several tankless heaters, including the Rheem 11kW 240V and Westinghouse 14kW models, offer continuous hot water with features like digital temperature control and self-modulating power to meet demand without running out.
Best Tankless Water Heater For Shower: Top Picks
| Image | Product | Buy |
|---|---|---|
Best Pick 1  | EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Best for: Small apartments | Check Price |
Best Pick 2  | Rheem 11kW 240V Tankless Electric Water Heater Best for: New homeowners | Check Price |
Best Pick 3  | Westinghouse Tankless Water Heater Electric 14kW 240V, Instant On-Demand Hot Best for: Budget heating | Check Price |
Best Pick 4  | Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater, GRAY Best for: Family showers | Check Price |
Best Pick 5  | NEW Rinnai RX199iN Condensing Smart Sense Natural Gas or Propane Best for: Smart homes | Check Price |
How We Picked
We meticulously evaluated numerous tankless water heaters to identify the best tankless water heater for shower applications. Our selection process prioritized build quality, real-world performance, and essential safety features. We ruled out units lacking consistent temperature control or robust construction, focusing on those offering excellent durability and standout capabilities.
Models were compared based on flow rate, energy efficiency, and user-friendly operation, ensuring they deliver reliable, on-demand hot water. Ultimately, we chose heaters providing exceptional value through their dependable performance and advanced technology.
What Most Buyers Get Wrong
Matching Flow Rate to Your Showerhead
For a satisfying shower experience, ensure your tankless heater’s Gallons Per Minute (GPM) output meets or exceeds your showerhead’s needs. Traditional showerheads use around 2.5 GPM, while low-flow models might use 1.5-2.0 GPM. Models like the Westinghouse Electric 14kW offer up to 3.38 GPM, which is ample for most showers, even multiple fixtures running simultaneously.
Rheem’s 11kW model provides up to 2.68 GPM. Always check your specific showerhead’s GPM rating to avoid lukewarm surprises.
Understanding Electric vs. Gas for Showers
When choosing a tankless water heater for your shower, consider the power source. Electric models like the EcoSmart ECO 11 require significant amperage and may necessitate an electrical panel upgrade, but they offer precise temperature control. Gas models, such as the Rinnai RX199iN, are generally more powerful for whole-home use and don’t strain your electrical system, but require proper ventilation.
For a dedicated shower, an electric unit with sufficient kW (like the 11kW or 14kW options) is often a straightforward choice.
1. EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240
Best for: Space-saving, point-of-use powerhouse.
With a compact 11.5 x 8 x 3.75-inch size, this EcoSmart ECO 11 electric tankless water heater mounts directly where you need hot water, eliminating long pipe runs. Its 13kW output at 240V delivers consistent on-demand hot water without a storage tank, ensuring you never face a cold shower again.
This unit provides a 3.1 GPM flow rate and precisely maintains water temperature within 1 degree of selection, thanks to its continuously monitored water temperature and controlled flow. It boasts 13000 watts of power for efficient heating, and the wall-mount design frees up valuable floor space previously occupied by traditional tank heaters.
Pros
- Space-saving 11.5 x 8 x 3.75-inch dimensions
- Consistent temperature within 1 degree
- 3.1 GPM flow rate for demand
- 13kW efficient heating power
Cons
- Requires a 54A amperage draw, necessitating specific electrical circuit planning.
Ideal for apartments or small homes needing an efficient, on-demand hot water solution. Mount it at the point of use for immediate hot water at your sink or shower.
2. Rheem 11kW 240V Tankless Electric Water Heater
Best for: Simple controls, reliable performance.
Featuring an ON/OFF dial and adjustable digital temperature display, this Rheem 11kW electric tankless water heater offers straightforward control over your hot water. Its self-modulating power control dynamically adjusts output to meet demand, ensuring efficient operation for your daily needs.
This 11kW model provides up to 2.68 GPM, fed by standard 1/2″ NPT water connections. With a maximum temperature of 140°F and 99.8% efficiency, it delivers continuous hot water on demand. The unit operates at 240 Volts for robust performance.
Pros
- Simple ON/OFF dial control
- Adjustable digital temperature display
- Self-modulating power efficiency
- 2.68 GPM flow rate capacity
Cons
- Limited to a 2.68 GPM maximum flow rate, which may not be sufficient for simultaneous high-demand use at multiple fixtures.
Perfect for homeowners seeking a reliable and user-friendly electric tankless water heater for general use. It provides consistent hot water without the complexities of advanced smart features.
3. Westinghouse Tankless Water Heater Electric 14kW 240V, Instant On-Demand Hot
Best for: Smart home ready, high flow.
With a powerful 14kW heating system and a 3.38 GPM maximum flow rate, the Westinghouse electric tankless water heater provides instant, on-demand hot water. Its compatibility with Google Assistant, Alexa, and Wi-Fi offers smart home integration for convenient control and monitoring.
This 240V unit features a starting flow rate of 0.5 GPM, making it responsive for single uses. It requires a dedicated 60-amp breaker and 6 AWG wire for its hardwiring. The heater is ETL Certified, ensuring safety and quality, and has a 12-month warranty.
Pros
- 3.38 GPM maximum flow rate
- Smart home compatible (Google, Alexa, Wi-Fi)
- 0.5 GPM starting flow rate
- ETL Certified for safety
Cons
- Requires a dedicated 60-amp circuit breaker and 6 AWG wire for installation.
Ideal for households looking for a high-flow, smart-enabled tankless water heater. Use it for instant hot water in busy bathrooms or kitchens with multiple demand points.
4. Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater, GRAY
Best for: Shower optimized, precise temperature.
This Rheem 240V RTEX-13 residential tankless water heater is designed for optimal shower performance, including a Water-Saver Shower Head with a 1.5 GPM flow rate. Its external digital thermostatic control allows for precise temperature adjustments in 1°F increments, ensuring your perfect shower temperature every time.
Featuring durable, field-serviceable copper immersion heating elements, this 13kW unit delivers hot water with at least 99.8% energy efficiency. The LED display clearly shows your selected temperature, and the unit’s 4.8 GPM flow rate supports multiple hot water needs, while the included shower head conserves water.
Pros
- Includes 1.5 GPM Water-Saver Shower Head
- Precise +/- 1°F temperature accuracy
- Durable copper heating elements
- 4.8 GPM flow rate capacity
Cons
- The included shower head’s 1.5 GPM flow rate might be too low for users accustomed to higher flow rates from non-regulated fixtures.
Best for individuals or families prioritizing a precise and water-efficient shower experience. This heater ensures consistent temperatures and includes a shower head for immediate conservation benefits.
5. NEW Rinnai RX199iN Condensing Smart Sense Natural Gas or Propane
Best for: Versatile gas power, high capacity.
The Rinnai RX199iN condensing tankless water heater offers flexible indoor or outdoor installation and uses either natural gas or propane, powered by a Smart Sense gas control system. It provides an impressive flow rate of up to 11.1 GPM, capable of supplying hot water to multiple fixtures simultaneously.
This compact unit, about the size of a small suitcase, outputs 199,000 BTU/hr and boasts a High (UEF .98) efficiency rating. It operates on 120 Volts and features a 11 GPM flow rate, making it suitable for larger homes and high-demand scenarios. An outdoor vent cap (RX-OVC) is required for exterior installations.
Pros
- Up to 11.1 GPM flow rate
- Natural gas or propane compatible
- Indoor/outdoor installation flexibility
- Smart Sense gas control system
Cons
- Requires a specific RX-OVC vent cap for outdoor installation.
This unit is ideal for larger homes or busy households that need substantial on-demand hot water capacity. Its dual-fuel capability and flexible installation make it a versatile choice.
6. Stiebel Eltron Tankless Water Heater – Tempra 24 Plus –
Best for: Whole-house heating, advanced control.
The Stiebel Eltron Tempra 24 Plus tankless water heater utilizes patented Advanced Flow Control to automatically maintain your set water temperature, reducing flow slightly only if demand exceeds capacity. This ensures constant comfort and uninterrupted hot showers throughout your home.
With a substantial 24kW heating output and 240 Volts, this unit provides an endless supply of hot water without requiring venting. Its sleek, white design is space-saving, and auto-modulation contributes to energy efficiency. The maximum pressure it handles is 150 PSI.
Pros
- Advanced Flow Control for constant temperature
- 24kW high heating output
- Space-saving, sleek design
- No venting required
Cons
- A significant 24kW wattage requires substantial electrical capacity and a dedicated circuit.
This is an excellent choice for larger homes needing a powerful, whole-house tankless water heater. Its advanced temperature control ensures consistent comfort for all hot water needs.
7. BOSCH Electric Mini-Tank Water Heater Tronic 3000 T 2.5-Gallon (ES2.5)
Best for: Compact sink-side hot water.
The BOSCH Tronic 3000 T 2.5-Gallon mini-tank water heater provides convenient, point-of-use hot water directly at your sink, minimizing wait times. Its 2.5-gallon capacity and 1440-watt output are perfect for quick tasks like handwashing or rinsing dishes.
With thermal efficiency at 98%, this compact electric water heater measures 13.75 x 13.75 x 10.75 inches, fitting easily under most sinks. It plugs into a standard 120-volt outlet with a 36-37″ cord, simplifying installation as an independent unit or in-line with a larger system.
Pros
- Compact 2.5-gallon capacity
- Fits under sinks
- 98% thermal efficiency
- Plugs into standard 120V outlet
Cons
- The 2.5-gallon capacity is insufficient for continuous or high-demand hot water needs like showering.
Ideal for kitchens or bathrooms where instant hot water is needed for handwashing or small tasks. This mini-tank supplements your main water heater or provides dedicated hot water at a sink.
8. CAMPLUX 5L Portable Tankless Water Heater, 1.32 GPM Outdoor Propane
Best for: Portable outdoor showers, RVs.
Weighing only 10 lbs with a folding handle, the CAMPLUX 5L portable tankless water heater is designed for ultimate portability, making outdoor trips easier. It delivers 1.32 gallons of hot water per minute, instantly providing a warm shower after a day of activities.
This outdoor propane heater features a maximum output of 34,000 BTU/hr and a maximum pressure of 110 PSI. It includes multiple safety protections like anti-freezing, dry combustion, and flame failure protection. The unit operates at 3 Volts but is powered by propane.
Pros
- Lightweight and portable (10 lbs)
- 1.32 GPM instant hot water
- Multiple safety features
- Ideal for camping and RVs
Cons
- Relies on propane fuel, requiring a gas source for operation.
Perfect for campers, RV owners, or anyone needing hot water outdoors. Its portability means you can enjoy a warm shower wherever your adventures take you.
9. 110V Tankless Water Heater Electric, 3000W Tankless Electric Water Heater
Best for: Small space, basic hot water.
This 3000W 110V electric tankless water heater is constructed with stainless steel and ABS materials, featuring an LED display for temperature settings. It can raise water temperature by 82°F to 131°F in seconds, eliminating preheating and long waits for hot water.
Operating at 110 volts, this unit utilizes advanced technology for instant heating, with a flow rate adjustment to manage temperature rise (0.3 GPM for higher temp rise, 0.5 GPM for lower). The LED display allows easy selection between Fahrenheit and Celsius degrees, holding the power button for six seconds to switch. Its heat output is 10,236 BTU/hr.
Pros
- Instant temperature rise
- LED display for temp setting
- Durable stainless steel/ABS construction
- 110V operation for wider compatibility
Cons
- Limited to 3000W power, resulting in a lower GPM flow rate and may only be suitable for single-point-of-use applications or low-flow showers.
This heater is suitable for small applications like a single faucet or a low-flow shower where immediate hot water is desired. It’s a straightforward electric solution for basic hot water needs.
10. Westinghouse Apolo Mini 6.5kW Tankless Water Heater Electric, 240V Instant
Best for: Compact sink heater, specific use.
Designed as a point-of-use solution, this Westinghouse Apolo Mini 6.5kW electric tankless water heater delivers instant hot water specifically for a single kitchen sink or bathroom vanity. Its slim profile measures just 6.9”x8.1”x2.5”, fitting discreetly under most sinks.
Operating on 240 Volts with 6500 watts of power, this unit provides hot water up to 130°F. Features include anti-freezing and dry combustion protection, plus an LED display for ease of use. Professional installation is required to ensure safety, performance, and warranty validity.
Pros
- Compact 6.9”x8.1”x2.5” dimensions
- Instant hot water for single fixtures
- 240V power for efficient heating
- Anti-freezing protection feature
Cons
- Requires professional installation to maintain the warranty and ensure safe operation.
This Westinghouse mini-tank is perfect for providing immediate hot water at a specific sink, ending cold-water waits for washing or rinsing. It’s a dedicated solution for point-of-use convenience.
Flow Rate vs. Power: The Electric Tankless Trade-Off
When selecting an electric best tankless water heater for shower applications, the fundamental truth is that you are absolutely locked into a direct trade-off between flow rate and the unit’s power draw. That’s it. There are no shortcuts or magical workarounds.
Consider the Rheem 11kW 240V Tankless Electric Water Heater, boasting a flow rate up to 2.68 GPM. This is generally sufficient for a single shower or a low-flow faucet. However, if you try to run two showers simultaneously or one very high-demand shower alongside another fixture, you will experience lukewarm water, not hot.
The Westinghouse Tankless Water Heater Electric 14kW 240V, with its higher 14kW rating, can support a higher flow rate of 3.38 GPM, making it a better candidate for households with multiple simultaneous hot water needs or those craving a truly powerful shower experience. But this increased capability comes at a cost: a significantly higher current draw, necessitating a dedicated 60-amp circuit.
This is an electrical infrastructure consideration that cannot be ignored.
The EcoSmart ECO 11 Electric Tankless Water Heater, at 13KW, sits in a similar performance bracket to the Rheem’s 14kW model, and the Rheem 240V Heating Chamber RTEX-13 offers comparable power. The key takeaway across these units is that anything below 11kW is almost certainly going to struggle with sustained, high-demand showering, especially in colder climates where the incoming water temperature is lower, requiring more energy to heat. Similarly, the 110V Tankless Water Heater Electric, with its paltry 3000W power, is functionally useless for anything beyond perhaps a very low-flow sink in a temperate climate; its ability to raise water temperature by 82° F is meaningless if the flow rate is a trickle.
The Stiebel Eltron Tankless Water Heater – Tempra 24 Plus, while mentioning advanced flow control, effectively operates within these same power-to-flow constraints. If your home’s electrical service cannot support a higher amperage draw, you are fundamentally limited to lower flow rates, regardless of sophisticated internal electronics. This is why models like the CAMPLUX 5L Portable Tankless Water Heater and the BOSCH Electric Mini-Tank Water Heater Tronic 3000 T 2.5-Gallon, while offering instant hot water, are completely different categories, designed for point-of-use applications or portable needs, not whole-home or even single-bathroom primary showering.
Ultimately, the Westinghouse Tankless Water Heater Electric 14kW 240V is the clear choice for those who demand sustained, high-volume hot water from an electric tankless unit and have the electrical infrastructure to support it.
How to Choose the Best Tankless Water Heater for Shower
Flow rate requirements
For a single shower, aim for a minimum flow rate of 2.5 GPM. If you frequently run multiple fixtures simultaneously, like a shower and a faucet, or have high-flow showerheads, a unit capable of 4 GPM or higher is essential. Always check the GPM rating of your showerhead; a low-flow head reduces the demand on the heater.
Prioritize models with a GPM rating that comfortably exceeds your highest simultaneous demand to ensure consistent hot water. For the best shower experience with typical showerheads, select a tankless heater with at least 3 GPM capacity.
Energy source and efficiency
Choose between electric and gas tankless water heaters based on your existing infrastructure and efficiency goals. Electric models offer simpler installation with no venting but typically have higher operating costs and require substantial electrical capacity. Gas models, using either natural gas or propane, provide faster heating and are often more cost-effective to run, but necessitate proper venting.
Look for units with an Energy Factor (EF) rating of 0.90 or higher for optimal energy savings. For most homes seeking efficient operation, a gas model with a high EF rating delivers superior performance.
Fuel type considerations
The GPM requirement for your shower dictates the necessary fuel input (BTUs) for a gas tankless unit. Natural gas units are generally more affordable to operate than propane, but propane offers flexibility where natural gas lines aren’t available. For standard showers, around 150,000 BTUs is sufficient, but demanding multiple showers or high-flow fixtures means looking at models from 175,000 to 190,000 BTUs.
Proper, direct-venting is crucial for safety and efficiency with gas units. Opt for a natural gas unit with sufficient BTU output for your GPM needs to ensure steady, reliable hot water.
Temperature output and control
Ensure your tankless water heater can deliver your desired temperature consistently, even in colder climates. Aim for a model with a maximum temperature setting of at least 120°F, and prioritize units with digital temperature displays and thermostatic controls. These features allow for precise adjustments and maintain your set temperature regardless of incoming water temperature fluctuations.
For the most comfortable and reliable shower experience, select a unit that offers digital controls and can reliably heat water to your preferred setting, even during the coldest months.
Which Should You Choose?
- If you need a solution for a single sink or need hot water very close to the faucet, choose a compact, low-flow electric point-of-use heater.
- If you have high hot water demand for multiple showers or appliances simultaneously, look for a high-kilowatt electric unit with a flow rate of at least 3 GPM, or a powerful natural gas/propane heater.
- If you’re concerned about maintaining a consistent temperature even with fluctuating demand, seek out models with advanced flow control or self-modulating technology.
- If you live in a colder climate and need reliable hot water for showers, consider a higher-power electric unit (11kW or more) or a gas model with a strong heating capacity.
Quick Best Tankless Water Heater For Shower Buying Checklist
- Assess Shower Flow Rate: Determine the GPM your showerhead(s) use.
- Consider Simultaneous Use: Factor in other hot water demands running at the same time.
- Choose Energy Source: Decide between electric or gas models based on availability and cost.
- Verify Efficiency Ratings: Look for high Energy Factor (EF) for better savings.
- Check Temperature Control: Ensure the unit offers precise and stable temperature output.
- Review Venting Requirements: Understand the installation needs for gas-powered units.
Frequently Asked Questions
What Is The Minimum Flow Rate Needed For A Tankless Water Heater To Activate?
Most tankless water heaters require a minimum flow rate between 0.5 to 1.0 GPM to activate the heating element. This ensures the unit can effectively sense water flow and begin providing hot water. A lower flow can prevent the unit from turning on, leading to no hot water at all.
Can A Tankless Water Heater Supply Multiple Showers At Once?
Yes, a tankless water heater can supply multiple showers simultaneously, provided it has a sufficient GPM (gallons per minute) capacity. You need to calculate the total GPM required by all fixtures running at once, ensuring the unit’s maximum flow rate exceeds this combined demand for optimal performance.
How Does A Tankless Water Heater’S Efficiency Compare To A Traditional Tank Heater?
Tankless water heaters are generally more energy-efficient because they only heat water on demand, unlike tank heaters that continuously maintain a hot water reserve. This on-demand heating significantly reduces standby energy losses, leading to potential long-term cost savings on utility bills.
What Is The Typical Temperature Range For Tankless Water Heaters?
Tankless water heaters typically offer adjustable temperature settings ranging from 85°F to 140°F. This range allows users to customize their hot water temperature based on personal preference and safety needs. Precise thermostatic controls ensure the set temperature is consistently delivered.
Are Electric Or Gas Tankless Water Heaters Better For Shower Use?
The better choice between electric and gas tankless water heaters for shower use depends on your needs and existing infrastructure. Gas models generally offer higher flow rates for multiple fixtures, while electric models are often easier to install and may be more efficient in some areas.
Final Words
Investing in the best tankless water heater for your shower provides endless hot water and significant energy savings. These innovative units offer a continuous supply, eliminating the ‘cold shower’ surprise, and contribute to a more sustainable household. Upgrade your home with an efficient tankless system for ultimate comfort and convenience.