5 Best Tankless Water Heaters of 2025 for Instant Hot Water

Tankless water heaters have become a popular choice for homeowners seeking energy-efficient, space-saving, and reliable hot water solutions. By heating water on demand, these units eliminate the need for bulky storage tanks and reduce energy waste. However, with numerous models on the market, selecting the best one can be challenging. To simplify your decision-making process, we’ve rounded up the top 5 tankless water heaters in 2025, highlighting their features, benefits, and why they stand out.

1. Rinnai RU199iN Tankless Water Heater

Overview: Rinnai is a trusted name in the tankless water heater market, and the RU199iN exemplifies their commitment to quality and innovation. This natural gas-powered unit is ideal for larger households or properties with high hot water demand.

Key Features:

• Flow Rate: Up to 11 GPM, sufficient for multiple fixtures running simultaneously.
• Technology: Equipped with ThermaCirc360™ technology for faster hot water delivery.
• Energy Efficiency: Ultra-high efficiency with an ENERGY STAR® certification.
• Durability: Built with long-lasting heat exchangers and leak-detection systems.

Why It’s Great: The RU199iN’s ability to provide consistent hot water to multiple fixtures without compromising efficiency makes it a top choice. Additionally, its Wi-Fi capability allows users to monitor and control the system remotely, adding convenience.

2. EcoSmart ECO 27 Electric Tankless Water Heater

Overview: For smaller homes or point-of-use applications, the EcoSmart ECO 27 is a highly efficient electric option. It is known for its affordability and compact design.

Key Features:

• Flow Rate: Handles up to 6.6 GPM, ideal for moderate water demand.
• Technology: Self-modulating technology adjusts energy usage based on hot water requirements.
• Design: Sleek and compact, perfect for tight spaces.
• Energy Efficiency: 99% thermal efficiency, making it one of the most energy-saving models available.

Why It’s Great: The ECO 27 is easy to install and maintain, offering an economical solution for households with lower water usage. Its precise temperature control ensures consistent performance, even in areas with colder incoming water.

3. Takagi T-H3-DV-N Tankless Water Heater

Overview: The Takagi T-H3-DV-N is a powerful and compact natural gas tankless water heater designed for high-demand households. Its robust performance and energy efficiency make it a great choice for larger homes.

Key Features:

• Flow Rate: Up to 10 GPM, suitable for multiple simultaneous uses.
• Technology: Features condensing technology for improved energy efficiency.
• Energy Efficiency: ENERGY STAR® certified with a 0.95 UEF rating.
• Safety: Includes advanced safety features like freeze protection and troubleshooting diagnostics.

Why It’s Great: The Takagi T-H3-DV-N delivers consistent hot water for families with higher demands while maintaining efficiency. Its compact design and reliable performance make it a standout option for homeowners looking for durability and convenience.

4. Stiebel Eltron Tempra 36 Plus Tankless Water Heater

Overview: Stiebel Eltron’s Tempra 36 Plus is a German-engineered electric tankless water heater known for its advanced technology and energy-saving capabilities. It’s an excellent option for homes looking to lower energy costs without sacrificing performance.

Key Features:

• Flow Rate: Supports up to 8 GPM, perfect for larger households.
• Technology: Advanced Flow Control™ ensures a consistent water temperature by automatically adjusting flow rates.
• Energy Efficiency: 99% efficient, reducing energy bills significantly.
• Silent Operation: Designed for noise-free performance.

Why It’s Great: The Tempra 36 Plus stands out for its precision and efficiency. Its Advanced Flow Control™ technology prevents temperature fluctuations, providing a seamless user experience even when water demand is high.

5. Rheem RTGH-95DVLN Tankless Water Heater

Overview: Rheem is a well-known brand in water heating, and the RTGH-95DVLN exemplifies their expertise. This natural gas-powered condensing unit is ideal for energy-conscious homeowners who need a reliable hot water supply.

Key Features:

• Flow Rate: Up to 9.5 GPM, suitable for medium to large households.
• Technology: Built-in recirculation pump for instant hot water.
• Energy Efficiency: ENERGY STAR® certified with 0.94 UEF.
• Smart Features: Compatible with EcoNet™ app for remote management.

Why It’s Great: The RTGH-95DVLN’s combination of performance, efficiency, and smart technology makes it a standout choice. Its robust build ensures longevity, while the recirculation pump minimizes water waste.

Factors to Consider When Choosing a Tankless Water Heater

To select the best tankless water heater for your needs, consider the following factors:

1. Flow Rate (GPM)

Determine your household’s peak hot water demand by calculating the flow rates of fixtures you plan to use simultaneously. For example:

• Shower: 2.5 GPM
• Dishwasher: 1.5 GPM
• Washing Machine: 2 GPM

2. Energy Source

Decide between gas or electric models based on fuel availability, costs, and your home’s infrastructure. Gas units are typically better for high-demand applications, while electric models are more energy-efficient for smaller homes.

3. Energy Efficiency

Look for models with high Uniform Energy Factor (UEF) ratings or ENERGY STAR® certifications to ensure optimal energy savings.

4. Installation Requirements

Consider the installation costs and modifications required for gas lines, venting, or electrical upgrades. Professional installation is recommended for most models.

5. Warranty and Support

Choose a model with a solid warranty and reliable customer support to ensure long-term satisfaction.

Advantages of Tankless Water Heaters

• Energy Efficiency: On-demand heating reduces energy waste.
• Space-Saving: Compact designs free up valuable space.
• Longevity: Lasts 20+ years with proper maintenance.
• Unlimited Hot Water: Provides consistent hot water as long as demand doesn’t exceed capacity.
• Lower Risk of Water Damage: No storage tank means no risk of tank leaks.

Installation and Maintenance Tips

• Professional Installation: Ensure proper setup, especially for gas models requiring venting.
• Regular Maintenance: Descale units annually to remove mineral buildup, especially in hard water areas.
• Inspect Filters: Clean water inlet filters periodically to maintain efficiency.
• Monitor Performance: Use smart features to track usage and detect issues early.

Conclusion

Choosing the right tankless water heater can transform your home’s hot water experience, providing energy efficiency, convenience, and reliability. The Rinnai RU199iN, EcoSmart ECO 27, Takagi T-H3-DV-N, Stiebel Eltron Tempra 36 Plus, and Rheem RTGH-95DVLN are all exceptional options, each catering to different household needs.

By considering factors like flow rate, energy source, and efficiency, you can find the perfect unit to meet your requirements. With proper installation and maintenance, a tankless water heater is a long-term investment that delivers consistent performance and significant savings.